CA2376348A1

CA2376348A1 - Multi-phase energy absorbing and impact attenuating modules

Info

Publication number: CA2376348A1
Application number: CA002376348A
Authority: CA
Inventors: Lawrence R. Parisotto
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-03-13
Filing date: 2002-03-13
Publication date: 2003-09-13

Description

MULTI-PHASE ENERGY ABSORBING AND IMPACT ATTENUATING MODULES
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention pertains generally to mufti-layer honeycomb or foam core articles with or without facing sheets integrated to the core that form modules designed to enhance absorption of impact energy and attenuate a colliding body by plastically or elastically deforming, crushing or compressing upon impact. Energy absorbing honeycomb and foam core structures and articles are utilized in a variety of applications to absorb a range of relative impact energies from low, e.g., energy absorbing pads in running shoes, to high, e.g:, side collision impact absorbing panels in vehicle doors.
More specifically, this invention relates to mufti-layered honeycomb or foam core articles fused or bonded together by common facing sheets or surfaces, or otherwise fixed or positioned adjacent to one another to form an integral energy absorbing module in which the individual layers are generally designed and manufactured to provide a specified crush sequence within the module, mufti-phase energy absorbing response and attenuation of an impacting body of high and extreme impact energy. It will be understood that the term honeycomb core also includes modified honeycomb and honeycomb-like structures and that the term foam core includes any energy absorbing foam material or reinforced foam material that has compressive strength such as expanded polystyrene, expanded polypropylene or polyurethane foams.
The energy absorbing honeycomb or foam core panels and artioles may be designed to be effective for a single impact only, i.e., plastic deformation, or for multiple impacts, i.e., elastic deformation, by varying the material utilized. The panels or articles are positioned relative to one another in a specified configuration to transfer an increased or maximized amount of impact energy between layers within the integral honeycomb module to enhance its energy absorbing characteristics relative to single layer or single density energy absorbing structures. The energy absorbing modules are positioned to intercede in an impact between an incident body of variable mass and energy, e.g., a racecar, colliding with a receiving body of variable mass and energy, e.g., a concrete barrier, so used to not only absorb the impact energy of the incident body but also attenuate the incident body in a controlled and designated fashion. In this manner, the mufti-phase energy absorbing and impact attenuating modules will reduce damage to either the incident body itself, and in the ease of the incident body being capable of housing an occupant or occupants, the occupant or occupants thereof; or the receiving body, and in the case of the receiving body being capable of housing an occupant or occupants, the occupant or occupants thereof; or both.
The mufti-phase energy absorbing and impact attenuating modules described herein have broad and varied applicability in manufactured articles generally in the automotive field. Several articles are provided to demonstrate the inventiveness, novelty and utility of the claimed invention. The aspects of the invention described are a mufti-phase energy absorbing and impact attenuating barrier system for use with racecars and automobiles, a mufti-phase energy absorbing and impact attenuating core material for automobile bumpers, a mufti-phase energy absorbing and impact attenuating panel within a vehicle door or other vehicle structure, and a mufti-phase energy absorbing and impact attenuating component of safety equipment, e.g., a crash helmet. While specified in the context of the aspects described herein, the mufti-phase energy absorbing and impact attenuating modules may be used in any manufactured articles in which it is advantageous for the physical damage of the incident body and its occupants if applicable, or the receiving body and its occupants if applicable, to be reduced or minimized, regardless of the relative impact energy.
DESCRIPTION OF PRIOR ART
The structural and energy absorbing properties of honeycomb and foam core structures and articles are well known and have been previously described by those skilled in the art.
The aspects of this invention are primarily concerned with honeycomb cores and panels in linear or slightly contoured articles and foam cores or. articles in applications where moderate or highly contoured energy absorbing articles are required, e.g., the liner for a crash helmet. In all aspects of this invention though, the multiple honeycomb and foam structures or articles comprising the integral mufti-phase energy absorbing and impact attenuating modules are designed and manufactured to have multiple, mathematically related compressive strengths and thus a tunable, compound energy absorbing capacity. Energy absorbing articles of prior art typically utilize a single honeycomb structure or single polymeric foam and are limited to one energy absorbing response which may be altered only by altering the thickness or density of the article.
Generally, honeycomb is used in structural applications where strength and bending stiffness are required, but with a minimum of weight. One such example is the aerospace industry where

2 honeycomb panels made of aluminum or other materials are used extensively in the manufacture of aircraft. However, honeycomb is not only useful in structural applications where strength and weight are a concern, but also in impact-absorbing applications where strength and weight are a concern. Honeycomb has excellent impact-absorbing properties in its thickness direction because energy from an impact is dispersed throughout the honeycomb matrix. Since the cells of a honeycomb matrix are interconnected, energy from an incident, colliding body is not only absorbed by the cell or cells involved, but also those adjacent to the involved cells by nature of common cell walls.
Foam is also well known in energy absorbing applications. Foam articles consist generally of a vast network of minute three-dimensional cells resembling a honeycomb structure shaped in a pentagonal dodecahedron configuration (twelve five-sided planes). Foams may be either flexible or rigid. Flexible foams are primarily used in cushioning or shock absorbing applications while rigid polyurethane foams are primarily used as thermal insulators or other similar insulating applications.
Flexible polyurethane foam (FPF) is somewhat similar in structure to honeycomb in that the cells of the foam axe made up of two structural parts, cell walls (struts) and open window areas (voids). The strut and void structure allows air to pass through the foam when force is applied. The elasticity of the struts acts as a shock absorber and allows the foam to recover its shape after compression.
Honeycomb structures and properties are described in terms of their "T"
direction (Thickness), "L"
direction (Length), and "W ' direction (Width). The core is the central member of the honeycomb structure. Honeycomb can be manufactured through a variety of processes such as extrusion, injection molding, pressure molding, expansion and corrugation that results in a honeycomb core.
The resultant cells of the honeycomb core may be round, rectangular or polygonal in honeycomb-like structures but are commonly produced to be hexagonal in traxe honeycomb structures.
Modified honeycomb structures comprise honeycomb cells but may be modified in their structure, e.g., containing openings in the cell walls or junctions to modify the compressive properties of the honeycomb core. Honeycomb consisting of hexagonal cells may comprise true hexagonal cells, underexpanded hexagonal cells where the cell diameter in the L direction is greater than the cell diameter in the W direction (L>W), and overexpanded cells where the cell diameter in the W
direction is greater than the cell diameter in the L direction (W>L).
Typically, honeycomb cannot be

3 bent to form contours, though underexpanded and overexpanded honeycomb are capable of moderate contours.
It will be understood that a honeycomb panel is comprised of a honeycomb core and a facing sheet or sheets, and a foam panel comprised of a foam core and facing sheet or surface. A facing sheet is a flat sheet of material fused or bonded to the open ends in the T direction of the honeycomb or foam core. Honeycomb cores are capable of carrying transverse loads when produced with facing sheets bonded or fused to both sides of the honeycomb core in the T direction to produce a honeycomb panel that also carries tensile and compressive loads. The hare compressive strength of a honeycomb core is its ultimate compressive strength as measured in pounds (kilograms) per square inch (square centimeter) when loaded in the T direction. The stabilized compressive strength is the ultimate compressive strength of the honeycomb core when stabilized by a facing sheet bonded or fused to the honeycomb core, i.e., a honeycomb panel; when loaded in the T direction.
The stabilized compressive strength is greater than the bare compressive strength for identical ' honeycomb cores.
It is primarily the compressive strength in the T direction of the honeycomb or foam structure that is utilized for absorbing the energy of an impact. Once the ultimate compressive strength of the honeycomb or foam has been exceeded, it will typically deform plastically or elastically and crush uniformly, typically at a constant stress level depending on the core material and its density as measured in pounds (kilograms) per cubic foot (cubic metre). This constant stress level is defined as the crush strength expressed in pounds (kilograms) per square inch (square centimeter) and is described as the average crush load per unit cross-sectional area. The energy absorption capacity of honeycomb and foam cores and panels in the T direction are therefore predictable in load versus deflection measurements and can be engineered for specific energy absorption applications.
Advantageously, the embodiments described herein utilize multiple honeycomb or foam cores, articles or structures with different energy absorbing characteristics to provide for a mufti-phase energy absorbing and impact attenuating response.
As stated previously, honeycomb or foam cores will initially resist crushing until the bare or stabilized compressive strength is realized, and subsequently crush predictably at a crush energy that is less than the bare or stabilized compressive strength. Honeycomb cores can be caused to crush below the compressive strength through a process called precrushing or prestressing. It will be

4 understood that the terms precrushing and prestressing are considered synonymous. Precrushing allows the honeycomb core to crush at its crush strength upon impact without having to attain the stabilized or bare compressive strength. Advantageously, the embodiments described herein utilize both precrushed and non-precrushed honeycomb or foam core panels, articles and structures to provide for a mufti-phase energy absorbing and impact attenuating response.
Honeycomb or faam core panels also have shear strength in both the L and W
direction that is typically dependent on facing sheet material and facing sheet thickness. Shear strength in the L
direction is typically greater than that of the W direction. Shear strength is also an important characteristic of an energy absorbing and impact attenuating module as incident collisions may not be orthogonal to the surface of the module, but rather from a variety of incident angles. Thus, the energy absorbing and impact attenuating module must be capable of being resilient, i.e., having sufficient shear strength, along its L or W direction so as to prevent damage to the energy absorbing capability of the honeycomb panels due to piercing impacts from a incident body. Advantageously, the embodiments described herein utilize a sufficiently resilient facing sheet or protective apron to protect the integrity of mufti-phase energy absorbing and impact attenuating modules.
As stated previously, honeycomb or foam core panels, articles and structures have excellent impact-absorbing properties along their T direction because energy from an impact is absorbed and dispersed throughout cells of the honeycomb or foam matrix. This dispersion of impact energy generally occurs within an individual honeycomb or foam layer (infra-layer transfer) in prior art.
However, a transfer of impact energy from layer to layer of an integral module (inter-layer transfer) is important not only for enhancing impact energy absorption but also to prolong the time over which the impact energy is dissipated and attenuate the incident body in a designated and controlled fashion. A specified configuration of honeycomb or foam layers can be utilized to increase the transfer of energy within the energy absorbing module by producing a specified load versus deflection response and crush sequence of layers within the module as it crushes. This specified configuration of layers will also attenuate the incident body in a designated and controlled fashion thereby reducing damage to the incident body, receiving body, or both. It will be understood that an incident body is that body, e.g., a racecar, which is incident upon the energy absorbing module and causes an impact with it, while the receiving body is that body with which the energy absorbing module is in intimate association with, e.g., a concrete barrier or vehicle structure.

Energy absorbing articles utilizing a single honeycomb or foam layer of consistent configuration, density and structure are not only limited to infra-layer transfer of impact energy, but also provide only a single-phase response to impact energy. That is, the crush strength fox the honeycomb or foam core, panel or article, while both predictable and capable of being engineered to certain specifications, is of a single order. Once the honeycomb has fully collapsed in the T direction under the compressive load of the incident impact, the impact absorbing properties of the article have been exhausted and the honeycomb or foam core; panel or article effectively becomes solid causing a significant and abrupt change in impact absorption dynamics. Advantageously, the mufti-phase energy absorbing and impact attenuating module of the present invention utilizes a plurality of honeycomb or foam layers to produce a mufti-phase energy absorbing and impact attenuating response to an impacting body.
Due to-the variety of impact energies possible in the aspects of the present invention, e.g:, up to approximately 160 g (160 times the force of gravity) in racecar collisions with a.barner system, the energy absorbing and impact attenuating module of the present invention has several different energy absorbing layers and thus phases of energy absorption and impact attenuation body in which the impact absorbing properties are not readily exhausted upon high or extreme impact energies relative to single honeycomb panels. The mufti-phase response can be designed to be in general terms an approximation of a mufti-phase linear, exponential or logarithmic shaped load versus deflection response dependent on the application. In addition, the energy absorption and impact attenuation response can be advantageously designed to be synergistic with respect to the individual energy absorbing characteristics of the incident body, thereby creating a maximum summative response representing energy absorbing components of both the incident body and impacted body.
For example, the compressive strength of each of the honeycomb panels in a module can be designed to be synergistic with the impact absorbing crumple zones of the impacting racecar (e.g.
wheel and suspension components, nose cone) producing not only a mufti-phase energy absorbing and impact attenuating response, but also a mufti-phase energy absorbing and impact attenuating response that is synergistic with the energy absorbing and impact attenuating response of the racecar.
Advantageously, the mufti-phase energy absorbing and impact attenuating modules of this invention provide enhanced energy absorption due to an increased transfer of impact energy between honeycomb or foam layers of the module. This is accomplished by ordering individual layers within the mufti-layer module in a specified manner according to their properties, including precrushed and non-precrushed bare compressive crush strength, and precrushed and non-precrushed stabilized compressive crush strength. In this manner, a more compact and efficient energy absorbing and impact attenuating module can be created for high or extreme impact energies relative to single layer honeycomb or foam core structures or articles of equivalent or greater thickness in the T
direction, or mufti-layer honeycomb or foam core structures that do not enhance energy transfer within the honeycomb structures. The more compact and efficient energy absorbing and impact attenuating modules of this invention may be manufactured of materials classified as rigid and plastic, e.g., aluminum, in which only a single impact is required to be accommodated, or elastic or elastomeric materials, e.g., thermoplastic elastomers, of moderated or controlled rebound Where multiple impacts are required to be accommodated.
Advantageously, the embodiments of the mufti-phase energy absorbing and-impact attenuating modules described herein also provide for mufti-phase energy absorption and impact attenuation of multiple impacts with a limited "dead time" when utilizing materials that deform elastically. Due to the unpredictable nature of collisions involving incident bodies such as racecars or automobiles, it is not inconceivable that the primary impact of an incident body with a mufti-phase energy absorbing and impact attenuating module would be the only impact in the course of an uncontrolled accident, but rather it possible that another collision could impact the same portion of the mufti-phase energy absorbing and impact attenuating module before it be repaired or replaced.
Utilizing elastic materials that return to their original morphology within a minimum dead tame, that is the time the mufti-phase energy absorbing and impact attenuating module structures require to return from a crushed, deformed or compressed state to a sufficiently energy absorbing and impact attenuating, state and provide a specified percentage of their original mufti-phase energy absorbing and impact attenuating properties, allows for accommodation of multiple impacts.
Honeycomb structures of prior art have been commonly made of materials and adhesives that are classified as rigid and deform plastically, such as aluminum, fiberglass, carbon, NomexTM or even cardboard. Honeycomb structures manufactured from non-elastic materials are incapable of recovering once impacted and crushed. To enhance the energy absorbing capacity of honeycomb manufactured from rigid materials, multiple layers of honeycomb panels fused or bonded by common facing sheets have been utilized, each comprising different energy absorbing properties, e.g., from highest to lowest crush strength or vice versa. These examples of prior art, however, do not produce an enhanced transfer of impact energy nor do they specify or claim an optimum relationship between crush strengths of different panels. Alternatively, single layer modified honeycomb structures have been utilized to enhance energy absorbing capacity.
Single layer modified honeycomb structures, while capable of modifying the energy absorbing response, are constrained by the thickness T of the single honeycomb structure.
Those who have described mufti-layer honeycomb impact absorbing systems manufactured from plastic materials include Niermeski (1999, US Patent 6,004,066), who described an impactor for a moveable, deformable barrier simulating the front end of an automobile for the purpose of crash safety evaluation comprising a plurality of energy absorbing impact segments each comprising a plurality of layers of aluminum honeycomb having different crush strength characterized by increasing crush-strength of successive layers from the outer impact face.
Eskandrian et al. (1997) also described a mufti-compartment honeycomb material for use in a surrogate reusable test vehicle used by the United States Federal Highway Administration in crash tests named Bogie. The multi-layer honeycomb impactors described by Niermeski and Eskandrian et al. are designed to simulate a specific vehicle type in crash tests rather than provide optimum energy absorbing properties.
Those who have described single layer modified honeycomb structures include Bitzer (2001, US
Patent 6,245,408) who described a modified honeycomb structure in which the crush properties are modified and controlled by crush control surfaces that form openings through the cell walls at intersections to provide a reduction in crush strength of the honeycomb cell.
Bitzer claims a wide variety of crush properties for a given honeycomb achieved by varying the size, shape, number and location of the crush control surfaces within the honeycomb in preferred embodiments of aluminum, aluminum alloy or cellulose-based materials.
Due to the relatively inelastic materials utilized in mufti-layer or modified honeycomb structures of prior art, the impact absorbing capabilities of inventions such as those of Niermeski and Bitzer utilizing multiple layers of honeycomb or a modified honeycomb structure are designed to be exhausted after a single, severe impact. Additionally, although multiple layers of honeycomb as described in prior art will provide for a mufti-phase energy absorbing chaxacteristic, no specification has been provided or claimed in prior art as to how to advantageously relate the energy absorbing properties of individual layers or increase transfer of energy from the impact throughout the g multiple layers of honeycomb or modified honeycomb structure to enhance the energy absorption and impact attenuating properties of honeycomb.
Literature on the energy absorbing and crush properties of mufti-compartment or mufti-layer honeycomb panels is not common. The embodiments and aspects of the present invention rely on a preferential crush sequence of layers and transfer of impact energy between layers of a mufti-layer energy absorbing module. Yasui (2000) indicates that in the case of a three-layer uniformed build-up honeycomb panel, the crushing of the panels occurred in the order of top panel (the panel facing the dropped-hammer impact), the bottom panel and middle panel in that order on drop-hammer testing. After perfect crushing of the top panel, the crushing of the bottom panel occurred from the center portion. After perfect crushing of both the top and bottom panel, the crushing of the middle panel occurred from the lower portion of the panel. Additionally, the number of crushing response steps in the load versus displacement data corresponded to the number of honeycomb layers. Yasui found that the energy absorption of the pyramid build-up type (prismatic streamlined) of mufti-layer panels was superior in efficiency and capacity in comparison to the uniform build-up type. Yasui also indicated that mufti-layer panels of the pyramid built-up type accompanied with the uniform build-up type can be expected to provide high performance impact energy absorption. Yasui's results indicate that the crush sequence of layers in a mufti-layer honeycomb module are not necessarily successive from one layer to its adjacent layer, and thus that impact energy can indeed be transferred between layers of a mufti-layer module. It is an object of the present invention to create a designated crush sequence of layers within the module to maximize the transfer of impact energy between layers of a mufti-layer energy absorbing module and enhance its energy absorbing performance.
Advantageously, the mufti-phase energy absorbing and impact attenuating module of this invention provides for an increased transfer of impact energy within the module by utilizing a plurality of honeycomb or foam layers with varying crush strengths, e.g., five discrete honeycomb panels, in a preferred configuration that produces a specified preferential crush sequence of maximally distal layers within the module and loading of non-precrushed layers that intercede between successive distal layers of the crush sequence with impact energy that is transferred between layers. By ordering layers within the module according to increasing crush strength and/or compressive strengths, and positioning the layers of increasing crush strength and/or compressive strengths maximally distal to its predecessor in the specified crush sequence in the module, a preferential crush sequence of layers is created in the module. Note that successive panels are placed preferentially maximally distal from their predecessor but may also be placed distal or adjacent to their predecessor. The variation in crush strength between layers is achieved by varying the structural properties of the individual honeycomb or foam core or panels, e.g., the core material used, density, core thickness, cell diameter, cell wall thickness, length of cell, presence of facing sheet, facing sheet material and thickness, and precrushing of honeycomb panel, to create successively increasing crush and/or compressive strengths in panels positioned adjacent, distal or maximally distal from their predecessor in the prescribed crush sequence of the honeycomb module.
Additionally, the successively increasing crush and/or compressive strengths in layers positioned adjacent; distal or maximally distal from their predecessor in the module are mathematically related to one another to produce an exponential, multi-phase linear or logarithmic shaped load versus deflection response of varying orders. Ultimately, the load versus deflection response will determine the deceleration of the incident body that characterizes its attenuation.
Prior art also describes the use of elastomeric materials in energy absorbing applications of honeycomb or foam. Utilizing materials of elastomeric composition in honeycomb or foam may provide resilience for multiple impacts. Utilizing materials of elastomeric composition may also increase the load bearing capability and enhance the article's ability to absorb high or extreme energy impacts. Utilizing an elastomeric composition that has a moderated or controlled memory for its original morphology and controlled rebound characteristics to resume that shape may both increase the load bearing capability of the article and its ability to absorb and attenuate multiple impacts. Thermoplastic elastomers (TPE) have been selected in energy absorbing applications due to their exceptional compressive, tensile and tear strength, resistance to puncture, and flexibility at low and high temperatures. Landi et al. (1991, US Patent 5,039,567) have utilized such a material in a honeycomb core for impact absorbing bumpers on an amusement ride.
Honeycomb and foam cores, panels and articles may not have the same physical properties in their T, L, and W directions, that is, they are generally anisotropic. Honeycomb consisting of overexpanded cells produced from thermoplastic elastomers and a fusion-bonding process may result in a flexible honeycomb that is anisotropic. Foam may be fibre-reinforced or otherwise modified to provide for increased compressive strength in its T direction.
Anisotropic honeycomb or foam may be designed with different attributes in its L, W, and T
directions allowing it to absorb energy and impacts from different angles: The impact absorbing properties of anisotropic honeycomb is affected by the physical properties of the honeycomb core, the facing material, cell diameter, thickness of cell wall and the thickness T of the core. Anisotropic honeycomb may also be used to produce contoured panels rather than linear panels and thus are useful in applications where contours are required, e.g., automobile bumpers. Thus, anisotropic, elastic honeycomb or foam can be engineered to absorb specific loads, to a desired flexibility, to a specific puncture resistance and to a controlled rebound. Advantageously, utilizing multiple layers of anisotropic, elastic honeycomb or foam in the energy absorbing and impact attenuating honeycomb modules of this invention provides for multiple impact, mufti-phase energy absorption and impact attenuation of an incident body in a variety of configurations that are compact and of more effective energy absorbing capacity than prior art.
In the first aspect of this invention, this invention relates to traffic barriers used to absorb and attenuate the impact energy of racecars colliding with barner systems that define the limits of race tracks including, but not limited to, oval, tri-oval, speedway, super speedway, temporary street circuits, road racing courses, drag racing or any combination of the former.
The mufti-impact, mufti-phase energy absorbing and impact attenuating barrier system of this invention is installed in intimate association with and in a prescribed alignment with existing concrete barner systems thereby interacting with incident colliding racecars from a multitude of incident angles and in a multitude of orientations to absorb energy and attenuate the impact of the racecar thereby decreasing the peak force of impact in multiples of the force of gravity (g-force) and increasing the time as measured in milliseconds over which the peak g-force is exerted thereby reducing injury to the racecar driver and damage to the incident colliding racecar. These factors are particularly significant in collisions between a racecar and an energy absorbing and impact attenuating barrier system because the length of time that impact energy is dissipated as measured in milliseconds is an important characteristic of the barrier system.
Automobile racing tracks require a barrier that defines the outer limits of the race track to prevent racecars from leaving the racing surface, and to contain any debris from the normal course of the racing event or racing collisions which occur during the racing event within the confines of the race track. Automobile racing tracks also require a barrier that defines a spectator area physically separate and remote from the racetrack to provide a safe environment for spectators. A necessary and increasingly important characteristic of this type of barrier that has emerged as racecar speeds have increased is that it must have some degree of energy absorbing and impact attenuating properties to minimize physical damage to racecars and racing drivers upon collision with the barrier.
Historically, a number of devices have been utilized primarily for the purpose of defining the outer limits of the racing surface or track and defining a remote spectator area -devices such as hay bales, dirt beans, wooden and metal railings, concrete abutments, wire fencing or combingtions of the above. In particular, steel fencing, such as Armco, and concrete abutments, such as concrete barriers with a rectangular surface parallel to and in a vertical orientation to the racetrack and attached wire containment fencing, serve as barners commonly utilized in European and North American automobile racing events respectively. Concrete barrier systems have become commonplace in North American racing because they are modular, not dislodged or damaged after an impact with an incident racecar, do not require repair within or between racing events, and have no associated parts that may be dislodged during the collision that cause a danger to other racing vehicles, drivers or spectators.
However, while the latter barner systems serve well to define the outer limits of the racetrack and contain ordinary or extraordinary racing debris, they do so by providing a fixed, hard surface ('hard wall'), and thus do not have any significant energy absorbing and impact attenuating properties to reduce peak impact forces and assist in preventing serious injury to a racing driver or significant damage to the racecar. The impact absorbing responsibility of such a collision lies solely with the racecar.
A commonplace and economical solution used in road racing applications is to supplement the existing racetrack barner system, e.g., concrete barriers; metal barriers and beans, with tire barriers consisting of used automobile tires lying horizontally and bundled several tires high in adjoining vertical columns, sometimes with a rigid tube placed in the tire opening of the vertical column, to provide energy-absorbing characteristics (refer to Federation Internationale de L'Automobile Standard 8861-2000, FIA Energy Absorbing Inserts for Formula One, Tire Barriers Standard).
These tire barriers are typically used in applications where the racetrack barrier system is at a distance from the racing surface itself such as may be the case in road racing circuits, that is, where a gravel trap or grass field intercedes between the racing surface and racetrack barner system.
However, tire barners are not useful in applications where the racing surface and barrier system are immediately adjacent to one another because significant impacts with an incident racecar during the event can dislodge the tire barner module itself or break the tire bundles causing the dislodged tires or associated hardware from the barrier to be a safety hazard to the racing event.
Those skilled in the art have previously described energy absorbing or attenuating elements in a plurality of barner modules manufactured of a variety of materials such as metal, polymers or rubber to be utilized for absorbing the impact of incident colliding vehicles.
Yunick (1997, US Patent 5,645;368) described a racetrack consisting of barrier modules including a base mounted on the barrier support surface delineating two crash barner rings circumscribing the racing surface with the inner ring in a juxtaposed relationship with the racing surface. Yunick's invention relates also to racetracks and their construction, more particularly to new vehicle racetracks constructed with novel and improved crash barners. However, the novel harrier method described by Yunick cannot be integrated easily, if at all, with existing barrier systems found at existing racetracks.
Muller (1998, US Patent 5,851,005) described the use of hexagonal metal elements to absorb incident impacts, however the impact-absorbing capabilities of such a device are exhausted after a single severe impact and afford no further impact-absorbing properties for collisions that may occur immediately after this first impact. Arthur (1999, US Patent 6,276,667) described the use of cylindrical elements of a rubber or polymer material that may retain their impact-absorbing characteristics after an initial severe impact: Muller and Arthur have both chosen to align the impact absorbing hexagonal or cylindrical elements such that the long axes are parallel and longitudinal to the vertical surface of the existing barner rather than orthogonal.. Such alignment provides for only limited collapse or compression of the elements as defined by the material, and width of the hexagonal or cylindrical elements. Moreover, longitudinal alignment of similar hexagonal or cylindrical elements does not provide for multiphase energy absorbing or impact attenuating characteristics.
More recently, those skilled in the art have considered barriers whereby materials of relatively low density, for example, low, medium or high density foam, have been placed in front of the existing concrete barrier system to provide energy absorbing and impact attenuating characteristics generally known as 'soft wall' barners. Due to the relatively low density of these materials, however, a significant depth of material is required to attenuate racing vehicles, thus decreasing the overall usable surface of the racetrack. Moreover, these materials are generally not resilient and a single impact may exhaust the energy absorbing and impact attenuating characteristics of such barners. In addition, unless a combination of materials of various densities is utilized in the soft wall barrier design, the energy absorbing and impact attenuating properties of such a system are also of a single phase.
Thermoset elastomers (TSE) consisting of cross-linked polymer chains have also been considered for soft wall applications. Safari Associates, lnc. utilize a material called MolecuthaneTM for soft wall applications in automobile racing. While TSE barriers may be designed with suitable energy absorbing and impact attenuating characteristics in their T direction, they are also limited to single phase absorption and attenuation and are also generally not recyclable as thermoplastic elastomers (TPE) are.
Other 'soft wall' burner solutions such as sacrificial inertial barriers that utilize frangible barriers containing energy absorbing dispersible mass including sand and water (Fitch, 1999, US Patent

5,957,616) have been described. A single, severe impact with the frangible barrier will not only exhaust its energy absorbing and impact attenuating capabilities, hut also may contaminate the racing surface with the dispersed energy-absorbing material.
In the application of an energy absorbing and impact attenuating barrier system for racing or other vehicles, an elastomeric material must have a controlled rebound characteristic to prevent impact energy from the collision being transferred back to the impacting body. A
controlled rebound property of an energy absorbing. and impact attenuating barrier system is critical in automobile racing because incident colliding racecars must have as much impact energy as possible absorbed and dispersed throughout the honeycomb or foam structure yet have a minimum of rebound to prevent energy from being transferred back to the incident vehicle causing either more.energy to be absorbed by the racecar structure or, in the case of a relatively elastic collision, cause the racecar to be propelled back into the race track, possibly into the path of oncoming racing traffic.
Accordingly, several objects and advantages of the mufti-impact, mufti-phase, energy absorbing and impact attenuating barrier system described herein are:

(a) the energy-absorbing characteristics of the barrier system are not exhausted after a single impact such as is the case in energy absorbing barrier systems utilizing a light density crushable material such as foam (Nelson, 1999,US Patent 5,860,762) or metal (Muller, 1998, US
Patent 5,851,005) that do not provide energy absorbing or impact attenuating characteristics for a secondary incident following the primary impact prior to repair being affected to said energy absorbing barrier system.
(b) the mufti-layered panels of the barrier system provide for a specific mufti-phase energy absorbing and impact attenuating response that inherently absorbs an increased amount of impact energy due to the transfer of impact energy between layers within the module as compared to the energy absorbing capabilities of prior art.
(c) the barrier system is relatively compact and integrated easily with the existing concrete barrier system as compared to other 'soft wall' designs so as to be practical and economical.
(d) the impact-absorbing and attenuating burner system elements are fixed with a minimum of hardware to the existing concrete barrier system in a manner that prevents elements from being dislodged or damaged such that they or debris from them may be dangerous to other drivers, vehicles or spectators.
(e) there are no dispersible elements of the impact-absorbing and attenuating barrier system that will interfere with the racing circuit or cause consequence to the race after impact and consequent rupture of the energy absorbing barrier such as is the case with frangible burners.
(f) the energy-absorbing characteristics of an energy absorbing and impact attenuating barrier system are mufti-phase due to different shapes, configurations, and physical dimensions of energy absorbing components rather than providing a linear or single phase attenuation due to the use of a single material of consistent density, shape, configuration or physical dimension.
(g) the energy absorbing and attenuating characteristics, because they are designed to be variable and mufti-phase, may be 'tuned' or engineered to certain specifications to be complementary and synergistic with the impact absorbing characteristics of the racecar or vehicle in use.

(h) the energy-absorbing and attenuating characteristics are designed such that in relative terms, in comparison to the existing concrete ('hard") barrier system, the impact absorbing and attenuating barrier system is:
relatively 'hard' for crash energy below approximately 5 to 10 times the multiple of the force of gravity (5-l Og) and the racing vehicle primarily absorbs the bulk of the impact, thus not sacrificing absorption characteristics of the wall for inconsequential collisions, nor having 'soft' portions of the wall that an incident racecar could interact with (e.g., puncture, get impeded by, get caught up with) in highly oblique collisions. This may be achieved by means of a sufficiently resilient facing sheet or protective apron positioned in intimate contact and in a prescribed fashion external to the honeycomb module and facing incident colliding bodies.
~ relatively 'firm', yet progressively more energy absorbing and impact attenuating for crash energy between approximately 10 to 40 times the multiple of the force of gravity (10-40g), and the racing vehicle and said impact absorbing and attenuating barrier system share in a synergistic manner the impact energy of the crash, ~ relatively 'soft' for crash energy above approximately 40 times the multiple of the force of gravity (40g) and the impact absorbing and attenuating barrier system absorbs a shared but increasingly larger portion of the impact energy of the crash. In this capacity, a mufti-phase energy absorbing and impact attenuating response, e.g., logarithmic or exponential, tuned to the incident body, e.g., an open wheel racecar, becomes increasingly significant.
(i) the energy absorbing and attenuating elements of the impact-absorbing and attenuating components can be easily reconfigured and 'tuned' for different applications (e.g., open wheel raeecars, closed wheel racecars) without involving an altered process of manufacture.
(j) that, where it is understood that the impact absorbing and attenuating barrier system is not required to be installed adjacent to the existing concrete barner system around the racetrack in its entirety, that contoured end-piece components be designed and manufactured to define the beginning and end of the energy absorbing and impact attenuating barrier system.

(k) the energy absorbing and attenuating barrier manufacturing process is well known to those skilled in the art and can be made of a materials familiar to those associated with the racing and tire industry thereby offering both an economical and practical advantage.
Further objects and advantages of the mufti-impact, mufti-phase energy absorbing and impact attenuating barrier system described herein are to provide an impact absorbing and attenuating barrier system in conjunction with existing concrete barrier systems that are inert to environmental forces, require a minimum of maintenance, and maintain a surface for other previously defined functions of the concrete barrier system, e.g: advertising.
Still further objects and advantages will become apparent from review and consideration of the ensuing description and drawings.
In the second aspect of this invention, this invention relates to a mufti-phase energy absorbing and impact attenuating core material for automobile bumpers. It is well known that automobiles may sustain front and rear impacts of varying energies during their routine operation. The use of front and rear automobile bumpers in automobiles in North America was mandated in 1925. Automobile bumpers generally serve two functions, one, to provide the esthetic function of extending downward the front and back bodywork of the vehicle with continuity to its overall shape, and, two, to perform the mechanical function of absorbing impacts of a variety of energies that the vehicle may sustain.
Those skilled in the art have devised methods involving metal bumpers, metal bumpers augmented by hydraulic or mechanical dampers, tubes, profiles or honeycomb structures.
According to Glance (US Patent 5799991, 1998) most contemporary automobile bumper systems consist of three basic components, a bumper beam, a bumper absorber, and a cover or fascia. The bumper beam is often metal, the bumper absorber is commonly a shock absorbing device or a polypropylene foam block, and the fascia is typically molded from a urethane plastic. Recently, thermoplastic elastomers (TPE) and thermoplastic polyolefms (TPO) have been used to manufacture molded, deformable, glass mat reinforced bumpers. Tusim et al. (2001, US Patent 6,213,540) describes an energy absorbing article of extruded thermoplastic foam that exhibits anisotropic compressive strength for use in light weight plastic automobile energy absorbing units.

More recently, hybrid steel/thermoplastic TPO bumpers have been described for lighter bumpers resilient to small impacts. The use of elastomers in molded bumpers and bumper fascias provides great design flexibility, lighter weight, improved resistance to impacts and corrosion, and the ability to recycle old or damaged bumpers.
The required energy absorption capacity of an automobile bumper directly relates to the weight of the vehicle, i.e., the heavier the vehicle, the higher the levels of energy absorbing capacity are required. Bumpers for light cars often utilize a metal or composite fiber reinforced beam fixed to the vehicle frame with a molded foam polypropylene energy absorbing block mounted between the beam and the fascia cover. Bumpers for heavy cars often utilize a metal or composite fiber reinforced beam mounted on hydraulic shock absorbing devices.
While many of these automobile bumper systems satisfy the requirements 2 miles per hour (4 kilometres per hour) and 5 miles per hour (8 kilometres per hour) impact tests, they have limitations. The energy absorbing and impact attenuating properties of existing systems may not be sufficient for high impact energies thereby causing a large portion of the impact energy to be transferred to the vehicle structure and thus the occupants of the vehicle.
Biomechanics would suggest that occupant injuries would be reduced if an enhanced absorption of impact energy could be isolated from the vehicle structure or occurred remotely from the vehicle structure itself. Due to the primarily single-phase energy absorption and impact attenuating characteristics of systems of prior art, the only way to increase the impact absorbing capacity involves increasing the dimensions and/or masses of the energy absorbing devices.
Advantageously, the mufti-phase energy absorbing and impact attenuating module of the present invention can be utilized as the absorber or core material of an automobile bumper with the T
direction of the honeycomb or foam core aligned generally parallel to the direction of front and rear impacts, i.e., parallel to the length of the vehicle. The individual panels or layers and overall energy absorbing response of the module may be tuned to the weight of the vehicle providing for a cost advantage by means of the same configuration of core material being used for light and heavy vehicles, but with a variation in structure creating appropriate energy absorbing and impact attenuating properties specific to the vehicle. The module ma.y be contoured to the shape of the bumper to serve both esthetic and impact absorbing functions. The honeycomb or foam modules of this invention when used as the absorber or core material for automobile bumpers may be fused or bonded on the one side to an outer foam component associated with the bumper fascia to provide resilience for multiple inconsequential impacts, and on the other side, to the inner beam component of the bumper, or be aligned in intimate contact with the energy absorbing crumple zone structure of the vehicle itself. The load versus deflection response of the module is designed with respect to the overall compressive strength of the front or rear crumple zones of the vehicle or other vehicle structures With which it is in intimate association with. The maximum transfer of impact energy between layers within the mufti-phase energy absorbing and impact attenuating module will isolate a greater amount of impact energy from the vehicle structure and thus the occupants of the vehicle, thereby potentially reducing morbidity or mortality of the vehicle occupants.
The mufti-impact capabilities of the mufti-phase energy absorbing and impact attenuating module utilized as a core material for bumpers also provides for energy absorption of secondary impacts, e,g., a rear impact from another vehicle may cause the impacted vehicle to careen out of control and collide with another body in the same area impacted by the primary impact.
Further advantages have been described in the other aspects of this invention.
Still further objects and advantages will become apparent from review and consideration of the ensuing descriptions and drawings.
In the third aspect of the present invention, this invention relates to a mufti-phase energy absorbing and impact attenuating module for a vehicle door or other vehicle chassis or cabin structure.
Automobile doors are constructed in a well-known manner typically comprising an inner and outer door panel. A decorative door trim panel is usually affixed to the inner door panel.
It is well known that automobiles may sustain side or other impacts of varying energies that intude upon the cabin during their routine operation. Those knowledgeable in the art have employed various means to absorb the impact energy of a side collision with an automobile to protect the occupants from injury. Metal beams have been positioned in vehicle doors to protect occupants from side collisions but offered little energy 'absorbing characteristics.
Foam materials, egg crate or cane shaped structures have been described whereby these articles. are positioned between the inner and outer door panels to provide energy absorbing capabilities. However, the space between the inner and outer door panel is typically small and varying in width and is intruded upon by various mechanical components making it difficult for low density, single-phase energy absorbing structures to be effective for higher impact energies involved in automobile collisions. More recently, side impact air bags have been utilized to protect vehicle occupants from side impacts, and while effective, are relatively expensive both in initial installment and repair.
Honeycomb has been described by those skilled in the art as an energy absorbing material for vehicle doors and other vehicle structures. Saathoff (1994, US Patent 5,306,066) whose assignee was the Ford Motor Company described a honeycomb shaped energy absorbing structure for absorbing energy from a side collision type impact of the door vehicle.
Saathoff listed advantages of his invention as being able to be tuned to meet side collision type impact requirements, having the honeycomb shaped energy absorbing structure precrushed to provide a lower crush strength, and being light weight and low cost compared to conventional foam material and cone shaped structures., However, Saathoff claimed only a single layer honeycomb structure made of precrushed aluminum, thus of single phase; plastic response.
Wielinga (2000, US Patent 6,117,520) whose assignee was AB Volvo (SE) described a honeycomb block useful as an impact force-absorbing element in a door of a vehicle comprising three sections of cardboard honeycomb elements characterized in that the cell size of each honeycomb element section decreases from a large size in one section to a smaller size in the neighboring section and an even smaller size in the third section facing inward with respect to the passenger compartment of the vehicle: While Wielinga claimed a mufti-layered honeycomb block that provides for a gradually hardened impact, he does not claim an embodiment that provides for a tuneable energy absorbing response, a preferred crush sequence or a means for maximizing the transfer of impact energy within the honeycomb block as described for the a mufti-phase energy absorbing and impact attenuating.module for a vehicle door of this invention. While claiming a progressively smaller cell size from the outer to inner sections of the honeycomb block, there is no consideration or relation of compressive or crush strengths of individual layers claimed by Wielenga, nor of an elastic response.
Advantageously, the mufti-phase energy absorbing and impact attenuating module for a vehicle door or other vehicle chassis or cabin structure of the present invention provides improved energy absorption due to the tunable and specified mufti-phase response in a limited space described in the previous aspects of this invention. The load versus deflection response of the module is designed to be complementary or synergistic with respect to the overall compressive strength of the door or other vehicle chassis and cabin structures that it is in intimate association with. In this application, the controlled and moderated rebound characteristics of the honeycomb module are not critical as in the first aspect of this invention, i.e., some energy from the collision may be transferred back to the impacting body. The multiphase energy absorbing and impact attenuating honeycomb module of this invention may also be utilized similarly in other vehicle chassis or cabin structures such as the Hrewall, dashboard, pillars, rear crumple zone and passenger safety cell.
Further advantages have been described in the other aspects of this invention.
Still further objects and advantages will become apparent from review and consideration of the ensuing descriptions and drawings.
In yet another aspect of this invention, this invention relates to a mufti-impact, mufti-phase energy absorbing and impact attenuating component of automobile safety devices, e.g., crash helmets. In particular, improvements on existing crash,helmet designs may be made by treating the crash helmet liner and shell as integral components of a mufti-layer foam and honeycomb energy absorbing module.
Generally, a crash helmet requires a strong, shatterproof outer shell and an inner liner that dissipates energyand cushions the head from sharp impacts to the shell. The outer shell is substantially spheroidal in shape and typically consists of an injection-molded thermoplastic or pressure-molded thermoset reinforced with fibres. The inner foam liner is commonly polystyrene, but may be polyurethane foam. According to Mills ( 1996), the crash helmet absorbs impact energy when the outer shell bends and the underlying foam deforms. The foam inner liner can compress by 90%
during an impact, thus provided cushioning of a blow to the head. However, if the maximum strain exceeds the 90% compression, then the foam becomes effectively solid and impact energy will be transmitted to the head. Thus, as is the case for the previous aspects of this invention, the energy absorbing capability of the foam inner liner is constrained by having single density foam of minimal thickness; as the foam approaches complete crushing due to the impact, it no longer absorbs impact energy causing an abrupt change in impact absorption dynamics, subsequently transferring impact energy back to the incident body to its detriment. Additionally, the energy absorbing response of the inner liner and outer shell are not well integrated. The total mass of the helmet is also a constraining factor in helmet design however; increased mass can add to -angular inertia of the head increasing risk of helmet roll off, though the increased mass may not increase the risk of neck injury.

Advantageously, the multi-phase energy absorbing and impact attenuating module of the present invention provides improved energy absorption due to the tunable and specified multiphase response in a limited space described in the previous aspects of this invention. In particular, the preferred embodiment of this invention in the aspect of a crash helmet involves multiple layers of foam of differing densities positioned intimately adjacent to one another in the inner liner, with the inner liner in intimate association with the outer shell comprising an inner and outer facing sheet of substantially a spheroidal shape and a honeycomb core integrated between the facing sheets. The outer shell is manufactured of a thermoplastic or thermoset material. 'The compressive strength of the inner liner foam layers and outer shell honeycomb are designed relative to one another such that the impact is firstly absorbed by the outer shell, then by a successive crush sequence of the foam layers of differing density of the inner liner.
Further advantages have been described in the other aspects of this invention:
Still further objects and advantages will become apparent from review and consideration of the ensuing descriptions and drawings.
Other aspects of this invention relate to a mufti-impact, mufti-phase energy absorbing and impact attenuating component of protective clothing or articles for sports or other applications, e.g., shin pads for hockey. Advantageously, the mufti-phase energy absorbing and impact attenuating module for protective clothing or articles for sports of the present invention provides improved energy absorption due to the tunable and specified multiphase response in a limited space described in the previous aspects of this invention.
Further advantages have been described in the other applications of the embodiments of this invention: Still further objects and advantages will become apparent from review and consideration of the ensuing description and drawings.
SUMMARY OF THE INVENTION
Briefly, in the present invention an energy absorbing and impact attenuating module is described that provides a multiphase; plastic or elastic absorption of impact energy and designated deceleration and attenuation of an incident body with an increased energy transfer between layers within the honeycomb module, and with the compound load versus deflection response of the module designed advantageously with respect to the overall compressive strength of the incident body or the structures with which it is in intimate association with, thus providing an energy absorbing and impact attenuating module tuned for a specific application.
More specifically, this invention relates to mufti-layered honeycomb or foam core structures or articles fused or bonded together or otherwise fixed or positioned adjacent to one another to form an integral module in which the layers are designed and manufactured to provide a specified mufti-phase plastic or elastic energy absorbing and impact attenuating response generally to an impacting body of high and extreme impact energies. The honeycomb or foam core structures or articles are positioned relative to one another according to crush and compressive strengths to create a specified crush sequence upon impact of layers preferably positioned distal or maximally distal to one another in the module so as to transfer an increased or maximized amount of impact energy between layers within the integral honeycomb module to enhance its energy absorbing characteristics. In mufti-impact applications, the elastic honeycomb or foam structures or articles are designed with an appropriate dead time to ensure their ability to respond to secondary or subsequent impacts relative to the application. The modules are positioned to intercede in an impact between an incident body of variable mass and energy, e.g., a racecar, colliding with a receiving body of variable mass and energy, e.g., a concrete barrier, so used to not only absorb the impact energy of the incident body but also attenuate it in a designated and controlled fashion. In this manner, the mufti-phase energy absorbing and impact attenuating modules will reduce damage to either the incident body itself, and in the case of the incident body being capable of housing an occupant or occupants, the occupant or occupants thereof; or the receiving body, and in the case of the receiving body being capable of housing an occupant or occupants, the occupant or occupants thereof; or both.
The present invention is applicable to a wide variety of honeycomb or foam structures or articles, made with a variety of materials generally classified as rigid, plastic, elastic, plastic, polymeric, elastomeric, or fibre reinforced elastomeric and has broad utility in providing relatively compact energy absorption and designated impact attenuation in a wide variety of specified compound load versus response parameters.
The above discussed and many other features, objects and advantages of the present invention will be better understood by reference to the following detailed description and accompanying drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
Referring now to the ensuing diagrams, a mufti-phase energy absorbing and impact attenuating module 10 is shown generally in FIG. 1 wherein said module is a component of an impact-absorbing barrier for racecars or highway barriers comprising several panels, each panel of which comprises a honeycomb or foam core and facing sheet or sheets, each core of which comprises a plurality of honeycomb or foam cells. An exemplary five-layer honeycomb module is shown generally in FIG. 2, FIG. 3 and FIG. 4 wherein said module is a component of an impact-absorbing barrier for racecars or highway barriers. The exemplary five-layer honeycomb module comprises honeycomb panels 11, 12, 13, 14, 15 and facing sheets 31, 32, 33, 34, 35. The honeycomb module is described as a uniform build-up type in which the panels are of the same length and width. It will be understood that the modules of the present invention may also be of the pyramid build up type in which the panel .or panels facing the incident body are of a smaller length and width than the back panels facing the receiving body producing a pyramidal build up of panels in the module.
An exemplary honeycomb core is shown generally at 12 in FIG. 5. The honeycomb has a length (L), a width (W) and a thickness (T). It will be understood that these same physical dimensions apply to foam core structures or articles. It will be also understood that the exemplary honeycomb 12 is one of multiple honeycomb, modified honeycomb or honeycomb-like cores or foam cores or articles in the mufti-phase energy absorbing and impact attenuating module 10 positioned to intercede in an impact between an incident body of variable mass and energy colliding with a receiving body of variable mass and energy so used to not only absorb the impact energy of the incident body but also attenuate it in a controlled and specified fashion. It will be further understood that the honeycomb core may be comprised of true honeycomb cells', honeycomb-like cells, over-expanded or under-expanded cells, or modified honeycomb cells and that the honeycomb or foam core may be manufactured of a variety of materials generally classified as rigid, elastic, plastic, polymeric, elastomeric or fibre reinforced elastomeric by processes including molding, extrusion, expansion and corrugation. Where mufti-impact energy absorbing and impact attenuating modules are desired, it will be understood that elastic or elastomeric materials will be utilized. While an exemplary module of five honeycomb, modified honeycomb or honeycomb-like panels is described, any number of honeycomb, modified honeycomb, honeycomb-like or foam cores, panels or articles greater than one may be used in the exemplary embodiment.

Several exemplary honeycomb cells 21, 22, 23, 24, 25 are shown in FIG. 6 with cell diameter (CD), cell wall thickness (CWT), and cell length (CL) identified. It will be understood that cells 21, 22, 23, 24, 25 may represent true honeycomb cells, honeycomb-like cells, over-expanded or under-expanded cells, or modified honeycomb cells and are repeated numerous times throughout each honeycomb, modified honeycomb or honeycomb-like panel. However, the cell type will be consistent in each individual honeycomb, modified honeycomb or honeycomb-like panel, and the density consistent in each foam core panel.
It will be understood that in general terms foam core articles comprising a vast network of similar cells comprising cell struts and voids will behave in a similax manner to honeycomb cores in their energy absorbing properties, though cross-linked polymer foams may have relatively superior energy absorption capacity in directions other than the T direction. Thus, while the exemplary module described comprises multiple layers of honeycomb panels, it will be understood that foam core layers or articles may also be utilized in one or more layers of the mufti-phase energy absorbing and impact attenuating modules of the present invention.
Facing sheets 31, 32 are shown generally in FIG. 7 as fused, bonded or otherwise fixed to the exemplary honeycomb core 12. The exemplary honeycomb panel 13 is generally considered to be comprised of honeycomb core 12 and facing sheets 31, 32. It will be understood that facing sheets 31, 32 are fused, bonded or otherwise fixed to adjoining honeycomb 11 and honeycomb 13 to form multiple layers of honeycomb panels in the mufti-impact, mufti-phase energy absorbing and impact attenuating module 10. Honeycomb 11, which is directed towards impacting bodies; may or may not have a facing sheet fused or, bonded to its outermost surface impacted firstly by an incident , , .
body, and is shown generally in FIG.1 as not having a facing sheet fused or bonded to its innermost surface. Honeycomb 11 may also be replaced by a foam core of cross-linked polymer construction.
Referring again to FIG. 3 and FIG. 4, the facing sheet 33 is fused, bonded or otherwise fixed to adjoining honeycomb 13 and honeycomb 14, facing sheet 34 is fused, bonded or otherwise fixed to adjoining honeycomb 14 and honeycomb 15, facing sheet 35 is fused, bonded or otherwise fixed to honeycomb 15 towards the receiving body thus forming multiple layers of honeycomb panels in the rnulti-phase energy absorbing and impact attenuating module 10. While impact energy is dispersed from cell to cell.in the honeycomb or foam matrix through cells with adjoining cell walls, the presence of facing sheets serves to further dissipate the impact load in two ways, one by further dissipating the impact energy along the front facing sheet facing the impact to non-impacted cells, and two, by further dissipating impact energy along the back facing sheet and to cells in the adjacent layer once the affected cells in the layer have fully compressed under the impact:
The whole honeycomb module 10 is generally constrained by a containment structure at the front, back, top, bottom and either sides of the honeycomb module to prevent the honeycomb or foam cores, panels or articles from being significantly displaced or crushed, compressed or deformed in a direction non-parallel with the T direction. In some instances, the containment of the honeycomb module l0 will be structures other than the pecified containment structure that the honeycomb module is in intimate association with, e.g., the bottom being the road, the back being the existing concrete barrier, the sides being adjoining honeycomb modules and the front and top being a protective apron in the aspect of the present invention described for use as a mufti-phase energy absorbing and impact attenuating barrier system for use with racecars and automobiles.
Each honeycomb panel 11, 12, 13, 14, 15 has specified crush, bare and stabilized compressive strengths based on the honeycomb core material, cell diameter (CD) of honeycomb cores 11, 12, 13, 14, 15, cell wall thickness (CWT) of honeycomb cores 1 l, 12; 13, 14, 15, cell length (CL) of honeycomb cores 1 l, 12, 13, 14, 15, and facing sheet 31, 32, 33, 34, 35 material and thickness. It will be understood that anisotropic foam cores or articles also have specified compressive and crush strengths based on the type and density of the core material.
In FIG. 8, an exemplary relative load versus deflection response graph is depicted representing the uniform and plastic or elastic deformation of an exemplary non-precrushed honeycomb panel when loaded. The bare compressive strength 5I is shown. The crush strength"52 of the exemplary honeycomb is also indicated and is less than the bare compressive strength 51.
Note that when the honeycomb or foam care has perfectly crushed, i.e., it has maximally crushed, compressed or deformed (the deflection approaches the thickness T), it effectively becomes solid and no further significant deflection can occur to absorb impact energy. It is vitally important that energy absorbing structures do not perfectly compress before the impact energy of a collision is significantly reduced because a significant amount of the impact energy can be transferred back to the incident body in an abrupt manner adversely affecting the impact absorbing dynamics of the energy absorbing and impact attenuating system. The use of mufti-layer energy absorbing modules with progressively increasing crush strength will reduce the likelihood of perfect crushing of the whole module and thus provide for a gradually increasing attenuation and more effectively absorb the impact energy of a collision.
In FIG. 9, an exemplary relative load versus deflection graph is depicted representing the uniform and plastic or elastic deformation of an exemplary precrushed honeycomb when loaded. Crush strength 57 is shown. Note that there is no bare compressive load peak required when the exemplary honeycomb is in the precrushed state before it deforms. Once again, when deflection approaches the thickness T, the crush strength rises dramatically and abruptly as the energy absorbing material effectively becomes a solid.
The exemplary mufti-phase energy absorbing and impact attenuating module 10 is generally shown in FIG. l, FIG. 2, FIG. 3 and FIG. 4 as comprising multiple layers of linear honeycomb panels. The layers may also be slightly contoured to accommodate the curvature of the receiving body, e.g., concrete barriers positioned in corners of the racetrack. The number of layers of honeycomb or foam cores, panels or articles of the modules of this invention may be any number greater than one, but must conform to a specified crush sequence based on position of the core, panel or article within the module, the relative and absolute bare, stabilized or crush strengths, and the state of the core, panel or article being either precrushed or non-precrushed. The exemplary mufti-phase energy absorbing and impact attenuating module 10 is produced wherein honeycomb panels 11, 12, 13, 14, 15 are positioned in a specific configuration according to relative crush, bare and stabilized compressive strengths as well as precrushed or non-precrushed states such that in the preferred embodiment the honeycomb panels will sequentially crush upon impact in the orderof 11; 15, 12, 14, 13 to maximize transfer of impact energy between layers, within the e~empla,ry mufti-phase energy absorbing and impact attenuating module 10. That is, in the crush sequence specified above in an exemplary honeycomb module in the preferred embodiment comprising five honeycomb panels 11, 12, 13, 14, 15, impact energy will be firstly absorbed by the crushing of the honeycomb panel 11 least resistant to the load and subsequently be transferred internally through the other layers of the honeycomb module to the maximally distal non-crushed honeycomb panel. In the preferred embodiment, after honeycomb panel 11 is fully compressed, honeycomb panel 15 will be next least resistant to the impact load as it is the non-crushed honeycomb panel maximally distal from honeycomb panel 11. By placing honeycomb panels 12, 13, 14 in a non-precrushed state and of greater compressive or crush strength between the honeycomb panel 11 first fully crushed and the successive honeycomb panel 15 in the crush sequence according to relative bare, stabilized or crush strengths in the preferred embodiment, further energy fram the impact can be absorbed by applying loads from transferred impact energy through the non-precrushed panels 12, 13, 14, thereby providing for a secondary energy absorption capability by causing some impact energy to be absorbed in the partial loading or precrushing of honeycomb panels 12, 13, 14. Advantageously then, impact energy transferred from honeycomb panel to successive adjacent, distal or maximally distal honeycomb panel in the crush sequence in the preferred embodiment is also dissipated by utilizing the transferred energy to load and partially precrush the successive honeycomb panels in the crush sequence. Note that the crush sequence of layers to achieve this secondary energy absorption capability maybe a variable, e.g. 11, 15, 13, 14, 12, but that it does not simply involve successive layers as is the case in a crush sequence of layers 11, 12, 13, 14, 15, in that order. The crush sequence of layer 1 l, 12, 13, 14, 15, in that order will however provide a mufti-phase energy absorbing and impact attenuating response. Research by Yasui (2000) indicates that with a three-layer uniform honeycomb panel module, the crush sequence of layers upon impact was the top layer, bottom layer then middle layer in that order. Yasui's results indicate that impact energy is transferred between layers of such a module and that crushing of layers in such a module is not sequential from top to bottom. Advantageously, the embodiments of the present invention utilize the relative and absolute properties of the individual energy absorbing layers to provide a crush sequence that enhances the energy absorbing capabilities in the modules of the present invention.
In the preferred embodiment, honeycomb panel 11 of the exemplary honeycomb module 10 least resistant to impact energy is positioned to face incident colliding bodies and is firstly impacted by an incident body. Honeycomb panel 11 need not have a facing sheet on the side of the honeycomb core facing the incident colliding objects. Instead, a protective structure, i.e., an apron 55, of metal, plastic or other material may intercede between the honeycomb module 10, specifically honeycomb panel 11, and the incident colliding object. In an alternative embodiment, honeycomb panel 11 may have a facing sheet fused, bonded or otherwise fixed to the side of the honeycomb core facing the incident colliding objects, also serving as a protective structure for the honeycomb module. In a third embodiment of this aspect, honeycomb panel 11 may have both a facing sheet fused, bonded or otherwise fixed to the side of the honeycomb core facing the incident colliding objects, and a protective structure of metal, plastic or other such material that intercedes between the honeycomb module 10, specifically honeycomb panel 11, and the incident colliding object to serve as a more substantial protective structure for the honeycomb module. Note that the combination of said protective structure and/or facing sheet must be sufficiently elastic to allow for the exemplary energy absorbing module 10 to react in its designed fashion.
Referring again to the preferred embodiment of the exemplary honeycomb module 10 in FIG. 1, FIG. 2, FIG. 3, and FIG. 4 depicting an exemplary mufti-phase energy absorbing and impact attenuating module comprised of five linear honeycomb panels, and the relative load versus deflection graph in FIG. 11, honeycomb panel 11 is in a precrushed state and has a crush strength CS 11 less than that of honeycomb panel 15 located maximally distal from honeycomb panel 11.
Honeycomb panel 15 is in a precrushed state and has crush strength CS15 greater than CS11, but less than that of honeycomb panels 12, 13, and 14. Honeycomb panel 15 is located maximally distal from honeycomb panel l I. After high or extreme impact energy of greater than CS 1 l, affected cells of honeycomb panel 11 will plastically or elastically deform and crush until the honeycomb core 11 is fully crushed and compressed: Once fully crushed, the affected cells of honeycomb panel 11 demonstrate no further deflection effectively becoming solid and are in a dead response time such that the energy from the impact is preferentially transferred through the honeycomb module from honeycomb panel 11 to honeycomb panel 15. After receiving sufficient impact energy of greater than CS 15, cells of honeycomb panel 15 will plastically or elastically deform and crush until fully crushed or compressed. Once fully crushed, the affected cells of honeycomb panel 15 demonstrate no further deflection effectively becoming solid and are in a dead response time such that the energy from the impact is preferentially transferred through the honeycomb module from honeycomb panel 15 to honeycomb panel 12. Honeycomb panel 12 is in a non-precrushed state and has a crush strength CS 12 greater than CS 15, but less than that of honeycomb panel 14 located maximally distal from honeycomb panel 12 allowing for the fact that honeycomb panels l l and 15 have plastically deformed, crushed fully, and are in a dead response time.
Cells of honeycomb panel 12 will have been partially loaded and in a partially loaded or precrushed state subsequent to the transfer of impact energy from honeycomb panel l l to honeycomb panel 15.
After receiving sufficient impact energy of greater than stabilized compressive strength SCS
12, cells of honeycomb panel 12 will plastically or elastically deform and crush until fully crushed and compressed. Once fully crushed, the affected cells of honeycomb panel 12 demonstrate no further deflection effectively becoming solid and are in a dead response time such that the energy from the impact is preferentially transferred through the honeycomb module from honeycomb panel 12 to honeycomb panel 14. Honeycomb panel 14 is in anon-precrushed state and has a crush strength CS14 greater than CS12, but less than that of honeycomb panel 13. Honeycomb panel 14 will be in a partially loaded or precrushed state subsequent to loading from impact energy transferred from honeycomb panel 11 to honeycomb panel 15, and honeycomb panel 15 to honeycomb panel 12.
After receiving sufficient impact energy of greater than stabilized compressive strength SCS
14, cells of honeycomb panel 14 will plastically or elastically deform and crush until fully crushed or compressed. Once fully crushed, the affected cells of honeycomb panel 14 demonstrates no further deflection effectively becoming solid and are in a dead response time such that the energy from the impact is preferentially transferred through the honeycomb module from honeycomb panel 14 to honeycomb panel 13. Honeycomb panel 13 is in a non-precrushed state and has crush strength greater than CS14, but less than the crush strength of the backing material with which it is in intimate association with, e.g., a concrete barrier of crush strength CSCo in the embodiment described for use as a mufti-phase energy absorbing and impact attenuating barrier system for use with racecaxs and automobiles. After receiving sufficient impact energy of greater than stabilized compressive strength SCS 13, cells of honeycomb panel 13 will plastically or elastically deform and crush until fully crushed and compressed. Once fully crushed, the affected cells of honeycomb panel 13 demonstrate no further deflection effectively becoming solid and are in a dead response time and the maximum energy absorbing and impact attenuating properties of the honeycomb module have been realized. If elastic materials have been utilized, the honeycomb module as a whole is then in a dead time mode for a short duration of time until the cores, panels or articles recover their original shape and size. Note that this exemplary description is for illustrative purposes of the concept the present invention and that the relative crush arid compressive strengths, precrushed or non-precrushed states, and crush sequence of panels within the module may be altered and thus tuned specifically to an application.
Generally, in the preferred embodiment of the exemplary module, the core thickness T11 and cell length of honeycomb panel 1 I CL 11 is greater than that of honeycomb panel 15, the core thickness T 15 and cell length of honeycomb panel 15 CL 1 S is greater than that of honeycomb panel 12, the core thickness T12 and cell length of honeycomb panel 12 CL12 is greater than that of honeycomb panel 14, and the core thickness T14 and cell length of honeycomb panel 14 CL14 is greater than that of honeycomb panel 13 resulting in an approximation of a logarithmic-shaped response as depicted in FIG. 11. Note that by altering the relative thickness of the cores of honeycomb paeels, e.g., T1 l~T'15<T12<Tl4<T15, different load versus deflection responses may be achieved, e.g., an approximation of an exponential-shaped response can be achieved as depicted in FIG. 13. The load versus deflection response depicted in FIG. 11 will decelerate the incident object relatively slowly at first, then progressively more quickly as the impact energy is absorbed and reduced due to the collision of the incident body with the first layer or layers of the module.
Such a response will provide controlled, tunable attenuation and more gradual absorption or cushioning response to the incident body.
Generally, in the preferred embodiment of the exemplary module, the cell diameter CD 11 of honeycomb panel 11 is greater than the cell diameter CD15 of honeycomb panel 15; the cell diameter CD15 of honeycomb panel IS is greater than the cell diameter CD12 of honeycomb panel 12, the cell diameter CD 12 of honeycomb panel 12 is greater than the cell diameter CD 14 of honeycomb panel 14, and the cell diameter CD14 of honeycomb panel 14 is greater than the cell diameter CD13 of honeycomb panel 13. Note that by altering the relative cell diameters of the cells of the honeycomb panels different responses may be achieved. Additionally, in the preferred embodiment; the cell wall thickness CWT 11 of honeycomb panel 11- is less than the cell wall thickness CWT15 of honeycomb panel 15, the cell wall thickness CWT15 of honeycomb panel 15 is less than the cell wall thickness CWT12 of honeycomb panel 12, the cell wall thickness CWT12 of honeycomb panel 12 is less than the cell wall thickness CWT14 of honeycomb panel 14, and the cell wall thickness CWT14 of honeycomb panel 14 is less than the cell wall thickness CWT13 of honeycomb panel 13. Note that by altering the relative thickness of the cell walls of the cells of honeycomb panels, different responses may be achieved.
Generally then, in the preferred embodiment of the exemplary module, the successive crush sequence of the honeycomb panels in the exemplary honeycomb module upon impact is honeycomb panel 11, honeycomb panel 15, honeycomb panel 12, honeycomb panel 14, and finally honeycomb panel 13. FIG. 11 demonstrates the individual relative load versus deflection response for the exemplary honeycomb module 10 comprising five layers of honeycomb panels relative to one another and superimposed on the same horizontal axis in the order of successive crush sequence.
FIG. 12 demonstrates an approximate logarithmic-shaped relative load versus deflection response graph for the exemplary honeycomb module 10 considering that the transferred impact energy from one honeycomb panel to another will also serve to load the successive non-precrushed honeycomb panels superimposed on the same horizontal axis in the order of successive crush sequence. FIG. 13 demonstrates an approximate logarithmic-shaped relative load versus deflection response graph for the exemplary honeycomb module 10 considering that the transferred impact energy from an individual honeycomb panel will also serve to load the successive non-precrushed honeycomb panel .
superimposed on the same horizontal axis in the order of successive crush sequence.
FIG. 14 demonstrates an approximate exponentially-shaped relative load versus deflection response graph for the exemplary honeycomb module 10 achieved by varying core thickness, cell diameter and cell wall thickness of layers in the module considering that the transferred impact energy from an individual honeycomb panel will also serve to load the successive non-precrushed honeycomb panel superimposed on the same horizontal axis in the order of successive crush sequence. Note that the load versus deflection response of FIG. 14 will quickly decelerate the incident object upon impact with the first layer or layers of the module and then decelerate it more slowly as the impact energy is absorbed and reduced.
FIG. 1I, FIG. 12, FIG. 13 and FIG. 14 demonstrate that the resultant relative load versus deflection curve and thus deceleration response to the incident body for the exemplary honeycomb module 10 can thus be tuned by nature of the core thickness, successive crush and compressive strengths, and crush sequence of the honeycomb panels of the honeycomb module. In some instances, an approximation of a logarithmic-shaped response may be most appropriate for a specific application, while in some instances an exponential or mufti-phase linear response may be most appropriate. The relative crush strengths, bare and stabilized compressive strengths of the exemplary honeycomb panels may be modified by cell length, cell diameter, cell wall thickness for a given honeycomb core material or by material and density of a foam core. The absolute compressive and crush strengths are designed with respect to expected impact energies and energy absorbing properties of the, incident body, in all aspects of the present invention though the resultant load versus deflection response and thus deceleration response is designed to attenuate the impact of either the incident body, receiving body or both. For example, in the aspect of the present invention wherein said mufti-phase energy absorbing and impact attenuating modules are an impact-absorbing barrier for racecars, the racecar (incident body) must be decelerated upon impact with the barrier (receiving body) in such a manner so as to minimize damage and injury. This may require a logarithmic shaped deceleration versus distance response in which the raeecar is initially decelerated relatively slowly while at high speed in the initial phase of the impact; and more quickly decelerated in later phases of the impact after some impact energy has been absorbed. In the aspect of the present invention as a crash helmet in which concentric, annular energy absorbing capacity of the layers of the inner liner and outer shell are integrated, the attenuation of the incident body is not of great concern, but rather the forces exerted on the head (receiving body) of the person wearing the crash helmet.
FIG. 14 illustrates an exemplary mufti-impact, mufti-phase energy absorbing and impact attenuating module in the preferred embodiment wherein said module is a mufti-phase energy absorbing and impact attenuating barner for use with racecars and automobiles capable of decelerating on impact a racing or other vehicle of very high speed over an extended period of time as measured in milliseconds at a significantly reduced multiple of the force of gravity (g-force) as compared to existing concrete barners thereby reducing the primary, secondary or tertiary impact g-force per unit millisecond. The barrier system is relatively compact and integrated easily by quick release fasteners 58 at 57 with the existing concrete barrier 51 as compared to other 'soft wall' designs so as to be practical and economical. The barrier system elements are fixed with a minimum of hardware 58 to the existing concrete barner system 51 in a manner that prevents elements from being dislodged or damaged such that they or debris from them may be dangerous to other drivers, vehicles or spectators. A protective apron 55 maintains the mufti-impact, mufti-phase energy absorbing and impact attenuating module 10 in intimate association and in a prescribed alignment with the existing concrete barrier 10, such that the "T" direction of the module is orthogonal to the vertical surface of the existing concrete barrier, and also prevents lateral, vertical orhorizontal displacement of module 10. The protective apron is substantially a reverse c-type configuration and is fixed and integrated with adjacent outer wall components in an overlapping fashion accounting for rotation or direction of racecars on the racetrack, consists of a smooth, hard outer surface of appropriate longitudinal strength that will nat bind significantly with a rotating race tire, and has an easement 56 along its inferior portion to assist with cleaxing track debris.
Upon impact by an incident racecar or vehicle, the incident body will firstly impact the protective apron 55 causing the impacted area to plastically or elastically deform inwardly towards the module 10. The impacted area of the protective apron will be displaced into the adjacent layer 1 l of the module 10. The module 10 will then behave as previously described herein to absorb the energy of the impact and attenuate the racecar or vehicle such that it decelerates in a prescribed fashion.
The mufti-phase energy absorbing and impact attenuating module 10 is designed to be sufficiently resilient to accommodate multiple impacts, and if damaged; is designed to be replaced in short period of time as defined by 'yellow flag' caution periods during a racing event.

Referring now to FIG. 15, FIG. 16 and FIG. 17, an automobile bumper is shown generally at 61. It is known that automobile bumpers of prior art consist of a bumper beam 62;
core 63 and fascia 64 and that the bumper core 63 is primarily responsible for providing energy absorption from incident bodies. The bumper beam 62 is often metal; the bumper core or absorber 63 is commonly a shock absorbing device or a polypropylene foam block, and the fascia 64 is typically molded from a urethane plastic.
The required energy absorption capacity of an automobile bumper 61 directly relates to the weight of the vehicle. While many of automobile bumper systems satisfy 2 miles per hour (4 kilometres per hour) and S miles per hour (8 kilometres per hour) impact tests, they have limitations. The energy absorbing and impact attenuating properties of existing bumpers may not be sufficient for high impact energies thereby causing a large portion of the impact energy to be transferred to the vehicle structure and thus the occupants of the vehicle. The only way to increase the impact absorbing capacity involves increasing the dimensions, density and masses of the energy absorbing devices.
Advantageously, the mufti-phase energy absorbing and impact attenuating module of this invention can be utilized as the core 10 of an automobile bumper with the T direction of the honeycomb or foam core aligned generally parallel to the direction of front and rear impacts; i.e., parallel to the length of the vehicle. The mufti-phase energy absorbing and impact attenuating module 10 is contoured to the shape of the bumper to serve both esthetic and impact absorbing functions.
Refernng to FIG. 17, the modules of this invention when used as the core 10 for automobile bumpers may be fused or bonded on the one side to an outer foam component 63 associated with the bumper fascia 64 to provide resilience for multiple inconsequential impacts, and on the other side, to the inner beam 62 of the bumper, or be aligned in intimate contact with the energy absorbing crumple zone structure of the vehicle itself. The load versus deflection response of the module is designed with respect to the overall compressive strength of the front or rear crumple zones of the vehicle or other vehicle structures with which it is in intimate association with. Thus, in a rear impact with a vehicle the bumper fascia 64 will firstly be impacted.
After the fascia 64 is fully compressed, impact energy will be transferred to the foam core 63 interceding between the module 10 and the fascia 64. After the foam core 63 fully or partially compresses, impact energy will be transferred to the mufti-phase energy absorbing and impact attenuating module 10, which will advantageously provide enhanced energy absorption and reduce the impact energy transferred to the bumper beam 62 or vehicle itself. The module 10 will behave as previously described herein to absorb the energy of the impact and reduce the impact energy transferred to the vehicle in a prescribed fashion.
Referring now to FIG. 18 and FIG. 19, a vehicle door 71 is depicted illustrating exemplary mufti-phase energy absorbing and impact attenuating modules 10 wherein said modules are for use within a vehicle door or other vehicle chassis structure. The outer door panel 71, inner door panel 72 and interior trim panel 73 are shown. In a side collision with the vehicle, the incident body will firstly impact the outer door panel 71 having a compressive strength CS71 causing it to plastically deform inwardly towards the driver or passenger of the vehicle. Subsequently, the inner door panel 72 having a compressive strength CS72 will be impacted causing it to plastically deform inwardly towards the driver or passenger of the vehicle. 'The mufti-phase energy absorbing and impact attenuating modules 10 will hen intercede in the impact between the inner door panel 72 and the driver or occupant 74. The compressive strengths and overall response of the modules 10 are designed in relation to the compressive strength of the inner and outer door panels CS71 acrd CS72.
The modules 10 will then behave as previously described herein to absorb the energy of the impact and reduce the impact energy transferred to the driver or occupant of the vehicle in a prescribed fashion.
Refernng now to FIG. 20 and FIG. 21, FIG. 20 depicts a crash helmet 80 of prior art. An impact with the crash helmet will firstly impact the outer shell 81 causing it to deform or bend and deform the underlying foam liner 82. The inner foam liner 82 provides a cushioning barrier for the head and may compress up to 90°!0 of its initial thickness. The comfort liner 83 serves to provide a comfortable fit for the helmet but also provides some cushioning of shock to the head as well.
Helmets also generally comprise a lower liner 86, visor mount 85, edge beading 84 and a chinstrap assembly 87:
FIG. 21 illustrates an exemplary mufti-phase energy absorbing and impact attenuating module 10 comprising the outer shell 91 and inner liner layers 92, 93, 94 and comfort foam 95 in the aspect of a crash helmet. In the preferred embodiment, the outer shell 91, inner layers 92, 93, 94 and 95 are concentric and annular. The outer shell comprises an injection or pressure molded honeycomb panel comprising an inner core 98 and facing sheets 99 made of thermoset or thermoplastic material that may be glass fibre reinforced. The outer Shell 91 has improved compressive strength, shear strength and tensile strength as compared to the outer shell 81 of prior art. The inner liner comprises layers 92, 93, 94 of differing density or material generally manufactured of polystyrene or polyurethane foam fused, bonded or otherwise fixed adjacent to one another in a concentric annular arrangement.
The outer layer 92 infused, bonded or otherwise fixed adjacent to the outer shell honeycomb panel 91 in a concentric annular arrangement, as is the inner layer 94 with the comfort foam layer 95.
The module 10, i.e., layers 91, 92, 93, 94 and 95, will then behave as previously described herein to absorb the energy of the impact and reduce the impact energy transferred to the head of the person wearing the crash helmet in a prescribed fashion.
Conceivably, those persons knowledgeable in this field of endeavor will, upon studying this disclosure, consider various modifications and/or improvements to~the inventive concept presented, but still within this concept. Though primarily designed for the preferred embodiments and aspects as mentioned herein, this in no way limits the use of the invention. In fact, similar rnulti-phase, energy absorbing and impact attenuating properties may be useful in a wide variety of applications in which energy absorption and impact attenuation of an incident body are desired. Therefore, the invention herein is not to be limited to the preferred embodiments and aspects set forth as exemplary of the invention, but only by he scope of the claims and the equivalents thereto.

[DRAWINGS]
Figure Figure 2 Figure Figure 4 Figure Figure 6 S

Figure Figure 8 Figure Figure 10 Figure Figure 12 Figure Figure 14 Figure Figure 16 Figure Figure 18 Figure Figure 20 Figure 21 REFERENCES:
Eskandrian, A., Marzougui, D., and Bedewi, N. Finite element model and validation of a surrogate crash test vehicle for impacts with roadside objects. FHWA/NHTSA
National Crash Analysis Center. Auburn, Virginia; 1997. Available [online]:
http://www.ncac.~wu..edu -Mills; N3-. Accident investigation of motorcycle helmets. Impact (Journal of the Institute of Traffic Accident Investigations). Vol. 5, Autumn, 1996, pp 46-51 Yasui, Yoshiaki. Dynamic axial crushing of mufti-layer honeycomb panels and impact tensile behavior of the component members. International Journal of Impact Engineering. Vol. 24;
No. 6. 2000: pp. 659-671.