GB2493392A - A panel including energy dissipating slots - Google Patents

Abstract

A structure for receiving an attachment or fixing, such as a panel or sandwich panel 10 is provided. The panel has a mount 12, configured on the surface of the panel 10 for securing an object to the panel 10 via a connector. The panel 10 includes a slot 14, configured adjacent the mount 12, wherein the slot 14 is configured to provide a low resistance load path 16 through which energy is distributable when a mechanical force is applied to the mount 12 in the direction of the slot 14. The panel 10 can be provided with a plurality of mounts 12 and/or slots 14.

Description

APPARATUS AND MOUNTING INTERFACE

The invention relates to an apparatus, or object, such as a panel structure, having a mounting interface configured to absorb energy when a mechanical load is applied to the interface. The invention also resides in structures having the apparatus such as vehicles, dwellings, aircraft and furniture.

Background of the invention

A known method of fixing one object to another, such as a fixing to a panel involves preparing a hole in the panel and securing a fixing therein, thus creating a connection between the two objects. When the connected objects experience opposing forces that, for example, forced them apart, the failure mode of the connection is often destructive, particularly when the load upon the fixing is sudden or dynamic. The failure mode typically involves (i) a failure of the fixing, which snaps if the panel is sufficiently rigid or (ii) a failure of the hole, or both, leading to destruction of the connection such that the two objects can separate. This can be disadvantageous in safety critical applications and situations, such as crash performance.

Summary of the invention

The invention generally resides in a structure, or apparatus such as a panel that can be connected to a bracket for receiving an attachment or fixing. The panel has a mount, or interface, for connecting thereto and an energy absorber configured adjacent the mount to provide a low resistance load path through which energy is distributable when a mechanical force is applied to the mount in the direction of the energy absorber.

In one aspect, the invention resides in a structure, or apparatus such as a panel that can be connected to a bracket for receiving an attachment or fixing. The apparatus, or panel, has a mount, configured on the surface of the apparatus for securing an object to the apparatus via a connector. The panel also has a slot, which functions as an energy absorber, defined by the apparatus, configured adjacent the mount. The slot is configured to provide a low resistance load path through which energy is distributable when a mechanical force is applied to the mount in the direction of the slot.

The mount, or interface, is configured to maintain the connection with an object connected to it. The connection can be maintained by inhibiting failure of a connector that secures the panel to the object and/or inhibiting the failure of the interface that receives the connector.

The connection to the mount can be a bolt, screw or similar connection. The load path can be substantially linear or can spread a load 0 and forks or fan out to distribute energy. The lowest resistance load path can pass directly through a slot. The load path can be configured to extend radially from the centre of the mount. The load path can be configured to pass substantially tangentially through the slots, when the slots are arranged concentrically. The slots can provide a path of lower resistance. The path of lower resistance can be configured to collapse or deform in a controlled manner to decelerate a fixing connected to the mount. A slot can provide a staged destructive process when a load is applied to the mount.

The energy absorber can be configured to inhibit failure of the connection with the panel. The energy absorber can be configured to control deceleration and/or the destruction of the panel adjacent the mount. In applications where a shock load is applied to the interface, such as an automotive vehicle application, the apparatus can be configured to control the deceleration for a known "crash pulse" or crash event to optimise the performance of the panel.

The apparatus can be a sandwich panel. The panel can have a plurality of layers. The panel can be substantially planar or curved. The mount can be defined by a hole in the apparatus. The mount can be a screw-mount, latch or hook connected to the panel via the mount. The mount can have a reinforcement member, shim or sleeve. The panel can have plurality of mounts.

The aperture of the or each mount can have a smooth surface or a non-smooth surface such as a substantially helical surface or a bayonet connection.

The slot can be an aperture, such as a hole, groove, aperture, recess, slot, or chamber. Such features are defined by the apparatus or panel. The mount can be a hole and the hole can be substantially cylindrical.

Alterntaively, a hole can be elliptical, square, triangular or hexagonal (maximum perimeter The slot can be formed in a layer of the sandwich panel structure. The 0 apparatus can be provided with a plurality of slots that are aligned to define a group of slots that provide a low resistance load path. The or each slot can be configured to enable progressive deceleration. The apparatus can be provided with a plurality of concentrically arranged slots. The slots can be configured adjacent the mount. A group of slots can provide a plurality of low resistance load paths. The or each group of slots can provide a low resistance load path. The or each slot can be formed in one layer, all layers, or only the core layer of a sandwich panel. A load path can pass substantially between adjacent slots or group of slots. The or each slot can be configured to be in fluid communication with mount. The or each slot can be configured to increase in width as it extends from the mount. The or each slot can be filled with energy absorbing material, such as energy absorbing gel. The or each slot can be configured with reinforcement members.

The shape of the slots are shown by way of example and are not limited thereto. The shape of the or each slot can be configured according to the load path, or multiple load paths to be implemented.

Overall, the invention can reside in a panel having: a hole/mount, configured on the surface of the panel and configured to receive a fixing; a recess, defined by the panel, and configured adjacent the mount, wherein a load applied to the mount in the direction of the recess deforms the panel in the region along the load path to absorb the load and maintain the integrity of the mount.

The panel can be adapted to absorb forces applied to the mount in a planar, direction to the surface of the panel.

The concept can be applied to the apparatus and panels disclosed in International Patent Applications W0201 1/010114 and W020 11/010115.

The panel can have a plurality of mounts. The or each mount can have a slot or group associated with the mount. A slot or group can be common to one or more mount.

In another aspect, the invention resides in a vehicle and/or a vehicle component, such as a body panel, chassis structure, seat component having 0 an apparatus or panel according to the invention.

In another aspect, the invention resides in a container for transporting goods having a panel or structure as described above. Such a container is configured to maintain its structure and inhibit the contents escaping in the event of a theft-attack, an explosive force within container or crash scenario.

Overall, the container functions to securely retain the contents of the container. The container can be configured to be bomb-proof.

In another aspect, the invention resides in a connection having a panel or structure as described above, an object connected thereto and a connector configured to secure the panel to the object. The object is releasably securable to the panel.

In light of the teaching of the present invention, the skilled person would appreciate that two or more aspects of the invention can be combined to form an improved panel or structure.

In the context of this document reference herein to vehicle is intended as reference to any form of conveyance such as, but not limited to, cars, trains, boats and airplanes. Further aspects of the invention will be

understood from the following description.

Brief description of the Figures

In order that the invention can be more readily understood, reference will now be made, by way of example, to the drawings in which: Figures la to ic are plan views of a portion of a panel configured according to the invention, wherein Figures la to ic show alternative configurations of the mount and the adjacent slots; Figures 2a to 2c are perspective views of a portion of a 3-layer sandwich panel configured according to the invention, wherein Figure 2a shows the slot formed in the uppermost skin only, Figure 2b shows the slot formed in each layer of the panel and Figure 3c shows the slot formed in the core layer only and the slot is enclosed to create a cavity or internal slot; Figure 3 is perspective view of a portion of a 3-layer sandwich panel configured according to the invention, wherein a plurality of slots formed in the uppermost layer of the panel are formed in fluid communication with the mount; Figures 4a and 4b show a test configuration of the panel; Figure 4c shows a portion of a 3-layer sandwich panel configured according to the invention, wherein a plurality of slots are formed in the uppermost surface only, adjacent a mount, and a mount with a fixing located therein; and Figure 4d shows 3 mounts according to the invention, two of which have fixings in place while one fixing has been removed to show the deformation of the panel after a load has been applied.

It should be noted that the relative dimensions of features illustrated in the Figures are not to scale. In particular the thicknesses of certain layers have been enlarged for ease of reference.

Detailed description of embodiments

The invention herein is described in relation to panels and, by way of example, honeycomb panels, honeycomb sandwich panels and sandwich panels. The invention is applicable to the panels and connections disclosed in International Patent Applications W02011/010114 and W02011/010115.

The invention may equally be applied to a panel comprising a single layer of material.

Figure ía shows a portion of an apparatus, or panel 10, which has a mount 12 for receiving an attachment or fixing. The mount is, by way of example, a through-hole that enables a nut and bolt to be securably fixed to 0 the panel. A slot 14 is defined by a recess in the panel 10 and in the present figures is a through-hole.

The slot 14 is located in the proximity of the mount 12. In plan-view the slot is arcuate in shape and follows a concentric path around the centre of the mount 12 at a given distance from the centre of the mount. If there were an imaginary circle centred on the mount 12 then the slot can be described as extending across a sector having an angle of approximately 40-degrees.

The dimensions in the figures are shown by way of example. A further slot 14 is provided further from the mount 12, and positioned adjacent the slot 14 closest to the mount. Each slot is substantially concentric with the mount and fits within an imaginary wedge, or sector, extending at 40-degrees from the centre of the mount.

A load path 16 is indicated by the arrow. The load path 16 indicates a low resistance load path through which energy is distributable when a mechanical force is applied to the mount 12 in the direction of the slot 14.

A load applied to the mount 14 in panel 10 that did not have a slot 14 would have a detrimental failure mode. Either (i) the fixing connected to the mount 12 would be sheared off, if the strength of the panel was greater that the strength of the fixing or (U) the force applied to the mount 12 would deform the panel 10 in the region of the mount 12 such that the integrity of the mount was compromised and/or the connection became unstable or detached from the panel.

According to the present invention, a load applied to the mount in the direction of the load path 16 experiences, initially, a lower mechanical resistance. The energy in the load is absorbed by compression and/or deformation of the slot 14, which as the effect of controlling the deceleration of the mount 12. As a result, a fixing secured in the mount 12 stays intact arid the deformation of the panel is a staged destruction process. The controlled deformation limits the total failure and/or inhibits release of a fixing located in the mount 12. The arrangement of the slot, or slots 14, inhibits tearing of the panel 10 and inhibits shock-release of a fixing located 0 in the mount 12.

In the event of a load upon the mount 12, the mount can deform in shape under the pressure of a fixing therein. By configuring the shape of the slot 14 and/or the arrangement of the group 15 the shape of the mount after a load has been applied can be determined. In other words, a slot functions to control the deformation of the panel.

A low resistance load path 16 can be created by a single slot 14 or by a group of slots 15. The group 15 extend in a radial direction. A slot 14, or group 15, will allow energy absorption from, for example, a high impact crash to start at the mount 12. The load upon the mount 12 created by the crash is applied in the direction of the load path 16 and the crash-pulse and energy travels in direction of the marked arrow.

In situations where crash performance can be anticipated the load path is configured to maintain the integrity of a connection to the mount 12.

The slots 14 can vary in size and/or shape and/or position in relation to the mount 12 to enable the desired result of the tearing action to distribute the energy. The slots distribute the energy in a deceleration manner i.e. by controlling the deceleration of the mount 12 within the panel 10. The slots 14 inhibit tear or shock release of the mount 12 from the panel. The slots provide a lower resistance path during initial energy inputs. The slots are configurable to create a staged destructive process.

The load path 16 is shown indicated by an arrow. It is not, however, limited to a single straight-line path. The arrangement of the slot of a group of slots can be configured to spread the load such that it forks or fans out to distribute energy. The load path can be said to extend radially from the centre of the mount, and pass substantially tangentially through the slots.

The slots can be arranged concentrically.

Figure lb shows a section of a panel 10, having a mount 12 and two groups 15 of slots 14 arranged on opposite sides of the mount. In the example shown the group 15 of Figure la is mirrored. Therefore, the two groups provide two load paths 16. This configuration provides dual directional control of energy absorption.

Figure lc shows a section of a panel 10, having a mount 12 and four groups 15 of slots 14 arranged at 90-degrees from each other such that they are equally spaced around the mount. In the example shown the group 15 of Figure la is provided four times. The four groups provide eight load paths 16. A load path is provided, substantially linearly, between the centre of the mount and the centre of a group 15. Additionally, a load path is provided, substantially linearly, between the centre of the mount and a mid-point between two groups. This configuration provides multi-directional control of energy absorption because a load applied to the mount 12 in any direction is applied to an area of the panel having, or being directly influenced by, the presence of a slot 14, or group 15.

To be clear, the controlled deceleration is enabled, in part, by the compression of the or each slot 14. Optimum absorption can occur when a load is applied to the mount 12 in a direction through the centre of a slot 14.

However, slots 14 can be arranged to create specific load paths 16 or multi-directional load paths 16 because, as shown in Figure lc, a load applied to the mount 16 in a direction between two groups 15 has the effect of compressing panel 10 material upon each of the groups.

The size of a slot 14 and the distance between a slot 14 and the mount 16 is determined by the material properties of the panel.

Figures 2a to 2c show the mount 12 and group 15 arrangement of Figure lb applied to a sandwich panel 18 having an upper skin 20, a core 22 and a lower skin 24. The mount 12 in each case is a through-hole. In Figure 2a the slots 14 are formed on the upper skin 20. In Figure 2b the slots 14 are formed on the upper skin 20, the core 22 and lower skin 24 to create through-hole slots. In Figure 2c the slots 14 are formed on the core 22 and are, therefore, enclosed.

The or each slot 14 can be configured on the or each layer 20, 22, 24 according to the energy absorption properties required. In other words, the configuration of the slots 14 can be varied.

If the panel is subject to impact through contact then the thickness of the skin on the contact side is less than the thickness of the skin on the non- 0 contact side.

Figure 3 shows an alternative slot arrangement wherein eight slots 14 are configured around a mount 12 on a sandwich panel 18. The mount is a through-hole. Each slot is formed on the upper skin 20 only. Each slot is open to the mount. In other words, each slot is in fluid communication with the mount 12. Each slot is narrower in the region close to the mount and widens at the opposite end.

The slots are equally spaced around the mount to create multi-directional tearing control. This configuration provides multi-directional control of energy absorption because a load applied to the mount 12 in any direction. A load would be applied to an area of the upper skin 20 located between a slot 14 or to an area between the slots 14, thus applying a load to two areas of the upper skin 20 located at each side of a slot.

Overall, the invention resides in an object, structure, apparatus or, as in the present example, a panel such as a sandwich panel, wherein a hole or mounting point is provided on the panel and is configured to receive a fixing.

Adjacent the fixing, in a position determined by the material type(s) and the direction in which energy is to be absorbed, are provided one or more recesses or slots, defined by the panel. The recesses are configured adjacent the mount. The recesses can be open to the mount and can reside on one or more layers or levels of the object or panel. Enclosed recesses can be described as apertures. When a load is applied to the mount in the direction of the recess, or between two recesses, the material deforms the panel in the region along the load path to absorb the load and maintain the integrity of the mount. The recesses create a load path of lower mechanical resistance in comparison with a mount located in an area of the panel that did not have recesses. In the event a force is applied to the mount and/or a fixing located in the mount, the mount and/or fixing travels through the panel by compressing the panel in the region of the recesses and/or deforms one or more of the slots 14. The load path functions to controlling the deceleration of the mount 12. As a result, a fixing secured in the mount 12 remains connected to the panel. The movement and/or deformation of the mount in 0 the panel is controlled by the recesses to provide energy absorption while inhibiting destruction of the panel and maintaining the intergrety of a connection to the mount.

The invention is particularly suited to applications in which a panel, having an object, bracket or other panel connected to it, is subject to an impact such as a crash pulse.

The applicants have tested the invention in a laboratory wherein a panel according to the invention is configured to represent a rear seat-back that separates the luggage compartment from a passenger compartment in an automobile. The regulatory standard for this test is ECE R17: Seat & seat anchorage strength & Luggage retention test.

Figure 4a shows the test cube positions above a panel according to the invention, which is held in place via 6 mounts, as shown. Figure 4b shows the dimensions of the panel with respect to the mounts.

Figure 4c shows two identical mounts. The leftmost mount is shown in the 3-layer sandwich panel configured according to the invention, wherein four slots are formed in fluid connection with the mount in the uppermost surface only. The slots are orientated in the direction of the load path. The right most mount has a fixing 26 located therein.

In the tests, the sandwich panel comprised a 15mm thick expanded foam panel (ARPRO 80 g/l) sandwiched between 1.5mm thick aluminium sheet (passenger side) and 0.5mm thick aluminium sheet (luggage side). By way of example, 3 test scenarios are described.

1. No slots provided adjacent the mount.

o A 52kg cube is applied at 5.77m/s to the panel. The energy of the load applied is 873].

a Result: * no shear or defomation at the fixings * both skins and ARPRO core intact * 125mm max deflection * deformation of brackets * bending of the panel around cube 2. Slots provided adjacent the mount. Designed to shear.

o A 52kg cube is applied at 6.66m/s to the panel. The energy of the load applied is 1164].

o Result: * both skins and ARPRO core intact * 121mm max deflection * deformation of brackets * bending of inrekor around cube * controlled shear helps to absorb energy * integrity of connection of panel to the brackets is maintained 3. Slots provided adjacent the mount (as per Figure 4c). Designed to shear.

o A 52kg cube is applied at 8.1Gm/s to the panel. The energy of the load applied is 1746].

a Result: * both skins and ARPRO core intact * 158mm deflection * deformation of brackets * bending of inrekor around cube * controlled shear helps to absorb energy integrity of connection of panel to the brackets is maintained Figure 4d shows 3 mounts, equivalent to those in Figure 4c, after a load has been applied according to the above-described test 3. Two of the mounts have fixings in place while one fixing has been removed to show the deformation of the panel in the direction of the slots after the load has been applied.

The slots 14 in the present examples are shown as voids, or recesses defined by the panel. The space, however, can be filled with a different O material such as an energy absorbing liquid, or gel. The mount 12 and/or a slot can be provided with reinforcement members. The energy absorbing properties can be tuned or adjusted by changing one or more of (i) the shape of the slot, (ii) the pattern the slot forms around the mount (iii) additional material provided in the mount and/or the slot (iv) reinforcement members provided in the mount and/or the slot A panel can be provided with a plurality of mounts 12, and one or more of the above features, alone or in combination, can be provided to optimise performance of the panel.

The present invention has been described above purely by way of example, and modifications can be made within the spirit and scope of the invention, which extends to equivalents of the features described. The invention also consists in any individual features described or implicit herein or shown or implicit in the drawings or any combination of any such features or any generalisation of any such features or combination.

Claims (1)

1. <claim-text>CLAIMS1. An apparatus for receiving an attachment or fixing, the apparatus having: a mount, configured on the surface of the apparatus for securing an object to the apparatus via a connector; a slot, defined by the apparatus, configured adjacent the mount, wherein the slot is configured to provide a low resistance load path through which energy is distributable when a mechanical force is applied to the mount 0 in the direction of the slot.</claim-text> <claim-text>2. An apparatus according to claim 1, wherein the apparatus is a sandwich panel.</claim-text> <claim-text>3. An apparatus according to claim 1 or 2, wherein the mount is defined by a hole in the apparatus.</claim-text> <claim-text>4. An apparatus according to claim 3, wherein the slot is an aperture.</claim-text> <claim-text>5. An apparatus according to claim 3 or 4, wherein the hole is substantially cylindrical.</claim-text> <claim-text>6. An apparatus according to any one of claims 2 to 6, wherein the slot is formed in a layer of the sandwich panel structure.</claim-text> <claim-text>7. An apparatus according to any one of the preceding claims, wherein the apparatus is provided with a plurality of slots that are aligned to define a group of slots that provide a low resistance load path.</claim-text> <claim-text>8. An apparatus according to any one of the preceding claims, wherein the apparatus is provided with a plurality of concentrically arranged slots configured adjacent the mount to provide a plurality of low resistance load paths.</claim-text> <claim-text>9. An apparatus according to any one of claims 7 or 8, wherein the or each group of slots provide a low resistance load path.</claim-text> <claim-text>10. An apparatus according to any one of the preceding claims, wherein the slot is in fluid communication with mount.</claim-text> <claim-text>0 11. An apparatus according to claim 10, wherein slot increases in width as it extends from the mount.</claim-text> <claim-text>12. A structure comprising a panel according to any one of the preceding claims.</claim-text> <claim-text>13. A vehicle having a panel or structure according to any one of the preceding claims.</claim-text> <claim-text>14. A seat for an automotive vehicle having a panel or structure according to any one of claims 1 to 12.</claim-text> <claim-text>15. A container for transporting goods having a panel or structure according to any one of claims 1 to 12.</claim-text>