JP2005233263A - Frp energy absorbing member structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an FRP shock absorbing member structure making use of the material characteristics of an FRP material. <P>SOLUTION: The shock absorbing member structure is made of an FRP material light and having a high strength as a shock absorbing member, in which the compression load and/or the energy absorption amount is increased more than conventional by making use of the compression or tensile strength in the fiber direction as the feature of the FRP material. That is, the compression load value and the energy absorption amount are improved by an FRP cylinder as the shock absorbing member and a pressing member equipped with a three-dimensional shape such that the end of the FRP cylinder makes split fracture in the cylinder axis direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure of an FRP shock absorbing member that realizes a high energy absorption amount.

  In order to improve the collision safety of automobiles and aircraft, a shock absorbing member and a shock absorbing structure that effectively absorb collision energy have been proposed. In particular, in the case of automobiles, the structure of a crash box or the like that effectively absorbs collision energy applied before and after the body is being studied. Generally, the impact absorbing member is required to be lightweight and have high rigidity.

  A composite material in which two or more kinds of materials are combined is an artificial material made for the purpose of obtaining excellent properties that cannot be obtained by the material alone, and has been developed for various purposes such as the purpose of strengthening the material. Of the composite materials, those obtained by reinforcing the materials with fibers are called fiber reinforced composite materials, and FRP (fiber reinforced plastic) is typical. FRP uses plastic as a matrix (base), and generally uses fibers such as glass and carbon as a reinforcing material.

  Among the FRPs, CFRPs formed of carbon fibers are known as UD materials (unidirectional materials) and cloth materials having different properties depending on the fiber orientation. The UD material is a material form in which carbon fibers are arranged in one direction and molded with an epoxy resin or the like. On the other hand, the cloth material is a material form in which carbon fibers are made into a woven shape and molded with an epoxy resin or the like. For example, the UD material has a property that the tensile force is strong in the length direction (longitudinal direction) of the carbon fiber, but the tensile force is weak in the length direction.

An impact absorbing member structure including not only an impact absorbing member made of such an FRP material but also a pressing member in contact with an end of the impact absorbing member has been proposed as improving the absorbed energy. That is, as the structure and shape of the pressing member, a structure and shape in which the shock absorbing member realizes a high energy absorption amount are being studied. For example, in Patent Document 1, in the compression deformation of an FRP cylindrical tube, a triangular protrusion serving as a starting point of destruction is provided in the shape of a pressing member installed at the tip of the FRP, thereby increasing the strength of the member and providing a form of destruction. It is an invention of an adjustable propeller shaft. Furthermore, Patent Document 2 discloses that a widening portion is provided on the pressing member, thereby increasing the load that can be withstood, preventing buckling of the FRP pipe, and adjusting the inclination angle of the widening portion, thereby increasing energy absorption than before. Disclosure. In addition, Patent Document 3 is an invention in which the recesses are provided in the pressing member, whereby the FRP cylindrical tube breaks down from the recesses to break the fibers and increase the amount of energy absorption.
Japanese Patent Laid-Open No. 07-091432 Japanese Patent Laid-Open No. 08-185969 Japanese Patent Application Laid-Open No. 07-224874

  In the conventional technology as described above, smooth delamination is generated by providing the pressing member with the widened portion and the concave portion, and the fiber is bent along the widened portion and the concave portion, thereby increasing the compressive load and the amount of energy absorption. doing. However, it cannot be said that these prior arts fully utilize the material properties of the FRP material. Generally, since the FRP material has a high tensile strength in the fiber direction, if the tensile direction due to fracture is the fiber direction of the FRP material, it is possible to cope with a larger compressive load, and an FRP shock absorbing member with better energy absorption. A structure can be realized. Accordingly, an object of the present invention is to provide an FRP impact absorbing member structure that takes advantage of the material properties of the FRP material.

  Therefore, as a result of intensive studies to achieve the above object, the present inventor has provided a cleavage induction structure that uses the strength of the cylindrical FRP in the fiber direction and promotes division in the cylindrical axis direction. By providing the pressing member, an impact absorbing member structure that realizes a larger load value and energy absorption than the conventional one is provided by taking advantage of the strength of the FRP material in the fiber direction. More specifically, the present invention provides the following impact absorbing member structure.

  (1) An FRP impact absorbing member structure comprising a cylindrical FRP formed of an FRP material that absorbs an impact due to a compressive load from a cylindrical axis direction, and a pressing member that contacts an end of the cylindrical FRP. The pressing member includes a cleavage guide structure that guides the longitudinal cleavage of the cylindrical FRP on the surface with which the end of the cylindrical FRP abuts, and the cylindrical FRP extends in the cylindrical axial direction. An FRP shock absorbing member structure that absorbs shock by dispersing a compressive load from a load in a fiber direction of the FRP material by edge cleavage by the cleavage induction structure.

  (2) The pressing member includes a pressing pedestal portion provided with a circular concavo-convex portion for guiding the cylindrical FRP, and a cleavage guide structure that guides cleavage in a length direction of the cylindrical FRP. The uneven portion of the shape is a hollow stump shape in which the inner peripheral side with which the cylindrical FRP abuts is convex and the outer peripheral side is concave, and the cleavage guide structure is one or more convex trigger parts. The FRP impact absorbing member structure according to (1), further including a pressing member in which the one or more convex trigger portions are arranged in a circular shape in a concave portion of the circular concavo-convex portion.

  (3) The FRP impact absorbing member structure according to (1), wherein the cleavage induction structure is detachable in an independent state.

  (4) The pressing member includes a pressing pedestal portion with which the cylindrical FRP abuts and a cleavage induction structure that induces the cleavage of the cylindrical FRP, and the cleavage induction structure is a combination of one or more irregularities. A concavo-convex structure including a boundary portion that is a boundary between a convex portion and a concave portion of the cylindrical FRP. The FRP impact-absorbing member structure according to (1), including a cleavage-inducing structure that causes cleavage of the FRP in the cylindrical axis direction.

  (5) The concavo-convex structure has a columnar shape or a polygonal columnar shape having an even number of corners formed by radially arranging so that one or more independent fan-shaped three-dimensional parts guide the cylindrical FRP. A concavo-convex structure having a shape, wherein one or more first boundary portions are generated by a boundary between the fan-shaped three-dimensional parts arranged radially, and each of the fan-shaped three-dimensional parts is formed in the fan-shaped radial direction. An unevenness is formed, and one or more second boundary portions are generated by the unevenness, and from the vicinity of the one or more first boundary portions and the vicinity of the one or more second boundary portions, the cylindrical axis direction (4) The FRP shock absorbing member structure according to (4), including a cleavage induction structure that cleaves the cylindrical FRP.

  (6) An automobile in which the FRP shock absorbing member structure according to any one of (1) to (5) is employed in an automobile crash box structure.

  (7) A buffering force improving method for improving a buffering force against a compressive load at the time of a collision of an automobile, wherein the cylindrical FRP is formed from an FRP material that absorbs shock by the collision, and contacts the cylindrical FRP. The end portion of the cylindrical FRP is cleaved by the cleavage guide structure provided in the pressing member, and the cylindrical FRP is A buffering force improving method in which a buffering force at the time of a collision of an automobile is improved by distributing a compressive load to a load in a fiber direction of the FRP material.

  By using the shock absorbing member structure of the present invention, when the FRP material is used for the shock absorbing member, it is possible to realize a larger compressive load than before and to realize a large energy absorption. That is, according to various FRPs that differ depending on the fiber orientation and fiber type, by using a pressing member equipped with a cleavage induction structure that is an optimal three-dimensional structure utilizing the strength of the FRP in the fiber direction, It is possible to improve shock absorption. Furthermore, since the designer can freely set the three-dimensional shape of the pressing member, it is possible to adjust how to promote the destruction of the fibers of the FRP material.

  Hereinafter, an example of an embodiment suitable for the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing the results of a compression test using cylindrical CFRPs having different fiber structures (inner diameter 80 mm, outer diameter 88 mm, length 250 mm) and pressing members having different three-dimensional structures in contact with CFRP. . The compressive load from the axial direction of the cylindrical CFRP was performed by bringing the pressing member into contact with the cylindrical CFRP, and the average load value (kN) and load fluctuation amount (%) at that time were measured. The value shown in the graph in the load characteristics is the average load value. As the CFRP material, a UD material and a cloth material were used. As the pressing member, one using a flat plate and the hollow stump-shaped member 200 which is a pressing member provided with the circular concavo-convex portions shown in FIGS. 2 (a), 2 (b) and 2 (c) were used. Here, the circular concavo-convex portion is a hollow stump shape in which the inner peripheral side with which the cylindrical FRP contacts is convex and the outer peripheral side is concave.

  Referring to the results of FIG. 1, the average load value of the flat plate is larger than that of the hollow stub-like member regardless of the material form such as the cloth material / UD material. For example, in a UD material, the average load value is 73 kN for a flat plate, but 48 kN for a hollow stub. However, in the load fluctuation amount, the hollow stub-like member is smaller than the flat pressing member. Therefore, a flat plate is more suitable as a pressing member in terms of average load value, but a hollow stub-like member is suitable in terms of load variation. Thus, the average load value of the hollow stub-like member is reduced when the cylindrical CFRP is bent and deformed by compression by contacting the pressing member, and the CFRP material layer between which the energy by compression is mainly laminated. It is because it is used to peel off. Since CFRP material is strong in tension or compression in the fiber direction, if the compression energy is consumed as tension / compression energy in the fiber direction by taking advantage of this strength, the average load value can be increased and greater energy absorption can be realized. it is conceivable that.

  The load fluctuation amount is the load area fluctuation area excluding the initial load fluctuation area where the load is applied, and the average value in that area is subtracted from the sum of the measurement maximum value and the measurement minimum value divided by 2. The value is divided by the average value. Further, the average load value is synonymous with the above-described average value, and is an average value in a load region change region excluding an initial load change region where a load is applied. As shown in the load characteristics of FIG. 1, a stable load value is maintained after the load exceeds the yield point and exceeds a certain displacement. However, it is desirable that the load value is small and does not drop rapidly. That is, the impact absorbing member or structure having a small load fluctuation amount is a member or structure that can stably absorb energy. Therefore, in order to obtain a shock absorbing member or structure with good energy absorption, it is desired to increase the average load value and reduce the load fluctuation amount.

  Although CFRP is used as FRP in the present specification, glass fiber, aramid fiber, boron fiber, silicon carbide fiber, and alumina fiber may be used, for example. Since the present invention relates to a structure of an impact absorbing member that takes advantage of the characteristics of fiber orientation, the type of fiber is not limited.

  The UD material is a material form of the CFRP material, and is a sheet-like CFRP material in which fibers are aligned and hardened in almost one direction as a carbon fiber structure, or a CFRP material obtained by laminating this sheet-like CFRP material. In general, the UD material may be a UD material in which the fiber direction of the sheet-like CFRP material is unified and laminated, but the fiber direction is different for each layer of the CFRP material, and may be laminated with a certain angle. Good. For example, the fiber direction is perpendicular to each layer. The UD material laminated with the fiber direction standardized is a CFRP material having anisotropy because the tensile strength in the fiber direction is strong, but the one with the fiber direction laminated perpendicular to each layer is isotropic. It becomes CFRP material which has. In the compression experiment of FIG. 1, a UD material formed by laminating sheet-like CFRP materials having fiber directions of 0 degrees and 90 degrees with respect to the cylindrical axis direction is used.

  The cloth material is a material form of the CFRP material, and is a sheet-like CFRP material oriented in a woven form by weaving fibers as a carbon fiber structure of the CFRP material, or a CFRP material in which this sheet-like CFRP material is laminated. is there. That is, the cloth material is a CFRP material in which a flat surface is formed by knitting one or a plurality of carbon fiber sleeves, and a matrix such as a resin is used for the flat surface. The knitting method for forming the woven shape may be plain weave or twill weave. Unlike unidirectional UD materials, cloth materials are generally CFRP materials that are isotropic in their strength.

  Next, when the same load value is applied in the fiber direction of the CFRP material, which strain is larger in the compressive load and the tensile load is examined.

  FIG. 3 is a stress / strain diagram when compression and tension of the UD material (fiber direction is only one direction) are performed in the fiber direction. The CFRP material used here was carbon fiber (T700S) manufactured by Toray Industries, Inc., and a resin (# 2500) was used as a matrix. According to this, the compressive stress of the fiber is less than half the tensile stress of the fiber. That is, compression greatly deforms with a small load, whereas tension performs small deformation with a large load. Therefore, as a characteristic of the UD material oriented in one direction, if the impact load is applied to the tensile load rather than the compressive load in the fiber direction, the deformation of the member is considered to be small. From this point of view, it is considered that an impact absorbing member structure utilizing the tensile load of the FRP material is desirable from the viewpoint of providing a shock absorbing structure having a large energy absorption.

  Table 1 shows compression of cylindrical CFRP (UD material in which sheet-like CFRP materials having fiber directions of 0 degrees and 90 degrees with respect to the axial direction of the cylinder are alternately laminated) in the compression experiment shown in FIG. Is a table showing the relationship between the form after deformation, the number of divisions in the cylindrical axis direction, and the average load value. Even if it is the same UD material, an average load value improves 30% or more by making a press member into a flat plate from a hollow stump-shaped member. When a flat plate is used for the pressing member, the deformation of the cylindrical CFRP due to compression results in double opening of the inside and outside of the cylinder. Since the hollow stump-like member has a concave shape on the outside of the cylinder and a convex shape on the inside, the direction of deformation is urged by compression and opens outward with respect to the cylinder, but does not open on the inside. Therefore, in the hollow stump-like member, the compressive stress due to the load is concentrated in the direction of opening the cylinder outward, and if the end of the cylinder is cleaved even at one place, the destruction of the part proceeds, resulting in an average load. It can be expected that the value is low. Further, the number of divisions in the axial direction of the cylindrical CFRP is larger for the flat plate. Dividing in the axial direction means cutting the fibers of the UD material having a fiber direction in a direction 90 degrees (cylindrical ring direction) with respect to the axial direction. That is, since the average load value is larger in the flat plate having a larger number of divisions at the end of the CFRP cylinder, the compression load is performed by utilizing the strength of the fiber in the case where the number of axially cleaved portions is larger. It is thought that.

  From this result, the tensile force in the fiber direction, which is a feature of the CFRP material, is utilized by guiding the pressing member so as to increase the axial division of the cylindrical CFRP, that is, the number of broken portions at the end of the cylindrical CFRP, and the load Considering the following examples, the increase in the value and the amount of energy absorption is considered.

  FIGS. 4A, 4B, and 4C are views showing the first embodiment. The pressing member 400 according to the first embodiment is a pressing member in which convex trigger portions 401 are circularly arranged in the concave portions of the circular concavo-convex portion of the hollow stub-like member 200. The trigger portion 401 is an example of a cleavage induction structure, which induces the cleavage of the cylindrical FRP in the length direction (cylindrical axis direction) and serves as a starting point for the end cleavage of the cylindrical FRP. The shape of the trigger part 401 may be a square shape or an arbitrary polygon. In FIG. 4, the trigger portion 401 is arranged with the circumference of the cylinder uniformly at an angle of 30 degrees in the concave portion of the pressing member, but the angle can be arbitrarily set by the designer. Moreover, it does not need to be uniformly arranged at a certain angle. The member of the trigger part 401 may be the same member such as steel as the pressing member, or may be different. Further, as shown in the pressing member 400, the height of the convex portion of the trigger part 401 is the same as the height of the concave portion outside the cylinder in the embodiment of FIG. 4, but it may be higher or lower than the height of the concave portion. Moreover, the height of the stump of the hollow stump-shaped member 200 that serves as a base for the trigger portion (the convex portion with which the inner side of the cylinder abuts) can be arbitrarily set, and the concave portion need not be provided on the outer side of the cylinder.

  As shown in FIG. 4D, a ring-shaped independent structure in which each trigger portion 401 is connected in a ring shape may be used. That is, the trigger part 401 can be attached in an independent state to the concave part on the outer peripheral side of the cylindrical FRP, and the trigger part 401 is arranged at a certain angle, whereby a plurality of trigger parts are formed into a hollow stump. The member 200 can be easily attached and detached. The shape of the detachable cleavage guide structure 450 in FIG. 4D is such that a plurality of trigger portions 401 are incorporated inside a donut-shaped circular ring that is cut into a ring. This is an example of the present invention. It is only shown. Therefore, when there is no concave portion on the outer circumferential side of the hollow stub-like member 200, a detachable cleavage guide structure 450 in which the trigger portion 401 is arranged on the circumference of the hollow disk may be used.

  FIGS. 5A, 5B, and 5C are views showing a second embodiment. According to the shape of the cylindrical CFRP 100, the pressing member 500 according to the second embodiment includes a cleavage guide structure 501 and a pressing pedestal portion serving as a pedestal of the structure on the inner side and the outer side where the cylinder abuts. The cleavage induction structure 501 is a concavo-convex structure and has a structure in which the end of the cylindrical CFRP is cleaved from the vicinity of the boundary of the concavo-convex. The concavo-convex structure in the embodiment of FIG. 5 is a concavo-convex structure in which two types of fan-shaped three-dimensional parts 505 and 506 are radially arranged independently to form a dodecagonal column as a whole. The fan-shaped three-dimensional parts 505 and 506 themselves are also provided with stepped irregularities having different heights in the radial direction (diagonal direction of the dodecagonal prism). That is, the fan-shaped surface areas of the fan-shaped three-dimensional parts 505 and 506 are divided into three, and the height differs depending on each area. The fan-shaped three-dimensional part 505 has a three-stage structure in which the height order is the outer side of the circumference, the inner side of the circumference, and the middle thereof, and the order of the height is the inner side of the circumference, the middle, and the circle. There is a second fan-shaped three-dimensional portion 506 that is a three-stage outer side. The fan-shaped three-dimensional parts 505 and the fan-shaped three-dimensional parts 506 are alternately arranged to form a dodecagonal cleavage induction structure 501. In addition, the boundary part between one fan-shaped solid part 505,506 and another fan-shaped solid part 505,506 is made into the 1st boundary part 510, and unevenness | corrugation of height which changes with the area | region which has in the fan-shaped solid part 505,506 is different. The boundary part of the part is defined as a second boundary part 520.

  In the embodiment, the cleavage induction structure 501 forms a dodecagonal column by the fan-shaped three-dimensional parts 505 and 506. However, this shape is only an example, and an arbitrary even number such as an octagonal column, a hexagonal column, or a 24-square column. You may form the polygonal column or cylinder which has this angle | corner. Further, the fan-shaped three-dimensional parts 505 and 506 may have three or more heights in the radial direction of the circumference, or may have two stages. Further, the cleavage induction structure 501 does not have to be hollow at the center, and may be provided with a recess in which the cylindrical CFRP is fitted in each fan-shaped three-dimensional portion in accordance with the thickness of the cylindrical CFRP.

  Table 2 compares the load fluctuation amount and the average load value of Examples 1 and 2 with a flat plate and a hollow stub-like member, as a CFRP, a UD material (stacked alternately at 0 degrees and 90 degrees in the cylindrical axis direction), a cloth material It is the result of having measured with respect to. The pressing member of Examples 1 and 2 is a result which greatly exceeds a flat plate in an average load value, and has improved 70% or more (Example 1) in UD material. Also, the load fluctuation amount was 3.8%, which is the same as the value of the hollow stump member. In Example 2, the load fluctuation amount using the cloth material shows a value less than that of the hollow stump-like member. That is, the pressing members of Examples 1 and 2 are pressing members having the advantages of both a flat plate and a hollow stub-like member in terms of an average load value and a load fluctuation amount. Therefore, the pressing members of Examples 1 and 2 provide a member that can realize a larger compressive load and energy absorption than conventional pressure members.

  In the pressing member according to the first embodiment, a trigger portion that is a cleavage induction structure that abuts on a thickness portion of the cylindrical FRP induces cleavage in the length direction of the cylindrical FRP. That is, the trigger site becomes an end portion starting point that divides the cylindrical end portion, and the cleavage is performed. Since the fiber direction of the FRP material can also be in the circumferential direction of the cylinder, cleavage in the axial direction means cutting the fibers in the circumferential direction. When further compressive load is applied, splitting is continuously performed from the cleaved part that is the starting point, but in order to perform splitting, the fibers in the circumferential direction must be cut, so a large compressive load is required. To do. Since the trigger part of Example 1 is arrange | positioned on the circumference at a fixed angle, the number of the cleavage parts used as the starting point of a split increases. Therefore, unlike when a hollow stump-like member is employed as the pressing member, the compressive load is not concentrated and broken at one cleavage part, and the destruction of the cylindrical FRP by splitting is performed in a plurality of locations. . That is, the compression load is distributed to the tensile force in the circumferential direction, which is the fiber direction, in order to perform further splitting from the cleaved portion by cleaving a plurality of portions of the cylindrical FRP. Therefore, it is inferred that a large average load value is realized by the pressing member of Example 1.

  In the pressing member according to the second embodiment, the first boundary portion 510 and the second boundary portion 520 of the cleavage guide structure 501 guide the cleavage in the length direction of the cylindrical FRP. That is, the vicinity of the boundary portion becomes an end portion starting point that divides the cylindrical end portion, and cleavage is performed. Since the fiber direction of the FRP material can also be in the circumferential direction of the cylinder, cleavage in the axial direction means cutting the fibers in the circumferential direction. When further compressive load is applied, splitting is continuously performed from the cleaved part that is the starting point, but in order to perform splitting, the fibers in the circumferential direction must be cut, so a large compressive load is required. To do. In the second embodiment, the first boundary portion is arranged by dividing the dodecagon at equal intervals, and the second boundary portion is arranged at a constant distance in the radial direction at equal intervals. The number of cleavage parts increases. Therefore, unlike the case where a flat plate is used as the pressing member, the compressive load is not concentrated and broken at one cleavage portion, and the destruction of the cylindrical FRP by splitting is performed in a plurality of locations. That is, the compressive load is dispersed in the tensile force in the circumferential direction, which is the fiber direction, in order to perform further splitting from the cleavage portion by cleavage at a plurality of locations in the cylindrical FRP. Therefore, it is presumed that the pressing member of Example 2 achieves a larger average load value than before.

  Furthermore, since the designer can freely adjust the size and height of the trigger part and the boundary part in the first and second embodiments, a cleavage induction structure having a desirable compressive load value and load fluctuation amount is produced. It is possible. Accordingly, it is possible to provide a pressing member having an optimal three-dimensional structure utilizing the strength of the FRP in the fiber direction in accordance with various FRPs that differ depending on the fiber orientation and fiber type.

  The FRP shock absorbing member structure of the present invention can be used in a crash box structure of an automobile. For example, by applying the pressing member of the present invention to a crash box that employs an FRP cylinder, it is possible to absorb the collision load applied to the front and rear of the body more efficiently than before.

  The present invention can also be provided as a method for improving the buffering force against a compressive load at the time of an automobile collision. As described above, by the cylindrical FRP formed from the FRP material that absorbs shock by collision and the pressing member, the cleavage guide structure provided in the pressing member cleaves the end of the cylindrical FRP, The cylindrical FRP is a buffering force improving method in which the buffering force at the time of a collision of an automobile is improved by dispersing the compressive load into the load in the fiber direction of the FRP material by cleavage. For example, in Examples 1 and 2, the compressive load is distributed to the tensile force in the circumferential direction, which is the fiber direction, in order to perform further splitting from the cleaved portion by cleaving a plurality of portions of the cylindrical FRP. This is a method in which the buffer force against the compression load is improved by the dispersion of the load.

  By using the shock absorbing member structure of the present invention for vehicles such as automobiles, two-wheeled vehicles, and airplanes, it is possible to provide a vehicle that performs shock absorption with higher energy absorption than before. That is, it is possible to provide a pressing member having an optimal three-dimensional structure that utilizes the strength of the FRP material in the fiber direction according to various FRP materials that differ depending on the fiber orientation and fiber type. Furthermore, since the shape of the pressing member in the shock absorbing member structure of the present invention can be freely set by the designer, how to split the fiber of the FRP material, what to do after the fracture, etc. From the viewpoint, the shape of the pressing member can be adjusted.

It is the figure which showed the result of the compression test using the CFRP material from which a fiber structure differs, and the press member from which a three-dimensional structure differs. It is the figure which showed the shape of the hollow stump-shaped member. It is a stress and strain diagram when compression and tension of a UD material are performed in the fiber direction. It is the figure which showed the 1st Example of this invention. It is the figure which showed the 2nd Example of this invention.

Explanation of symbols

100 Cylindrical CFRP
200 Press member 400 Press member 401 Trigger site 400 Press member 450 Detachable cleavage guide structure 500 Press member 501 Cleavage guide structure 505 Fan-shaped three-dimensional portion 506 Fan-shaped three-dimensional portion 510 First boundary portion 520 Second boundary portion

Claims (7)

A FRP shock absorbing member structure comprising a cylindrical FRP formed of an FRP material that absorbs shock due to a compressive load from a cylindrical axis direction, and a pressing member that contacts an end of the cylindrical FRP,
The pressing member includes a cleavage induction structure that induces the longitudinal cleavage of the cylindrical FRP on the surface with which the end of the cylindrical FRP contacts.
The cylindrical FRP is a FRP shock absorbing member structure that absorbs shock by dispersing a compressive load from the cylindrical axis direction into a load in the fiber direction of the FRP material by edge cleavage by the cleavage induction structure. The pressing member includes a pressing pedestal portion provided with a circular concavo-convex portion for guiding the cylindrical FRP, and a cleavage induction structure for inducing cleavage in the length direction of the cylindrical FRP,
The circular concavo-convex portion has a hollow stump shape in which the inner peripheral side with which the cylindrical FRP contacts is convex and the outer peripheral side is concave,
The cleavage-inducing structure is one or more convex trigger sites,
The FRP impact absorbing member structure according to claim 1, further comprising: a pressing member in which the one or more convex trigger portions are arranged in a circular shape in a concave portion of the circular concavo-convex portion.   The detachable cleavage induction structure according to claim 1, wherein the cleavage induction structure is removable in an independent state. The pressing member includes a pressing pedestal portion with which the cylindrical FRP abuts, and a cleavage induction structure that induces the cleavage of the cylindrical FRP,
The cleavage induction structure is a concavo-convex structure including a boundary part that is a boundary between a convex part and a concave part of a combination of one or more concavo-convex parts,
And a cleavage-inducing structure that causes the cylindrical FRP to be cleaved in the cylindrical axial direction from the vicinity of the boundary portion when the cleavage-inducing structure abuts against an end portion of the cylindrical FRP by the compressive load. Item 2. The FRP shock absorbing member structure according to Item 1. The concavo-convex structure has a cylindrical shape or a polygonal column shape having an even number of angles formed by radially arranging one or more independent fan-shaped three-dimensional parts so as to guide the cylindrical FRP. A concavo-convex structure,
One or more first boundary portions are generated by a boundary between the fan-shaped three-dimensional parts arranged radially,
Each of the fan-shaped three-dimensional parts forms irregularities in the fan-shaped radial direction, and one or more second boundary portions are generated by the irregularities,
5. The FRP shock absorption according to claim 4, further comprising: a cleavage induction structure that cleaves the cylindrical FRP in the cylindrical axis direction from the vicinity of the one or more first boundary portions and the vicinity of the one or more second boundary portions. Member structure.   An automobile in which the FRP shock absorbing member structure according to any one of claims 1 to 5 is employed in an automobile crash box structure. A method for improving a buffering force for improving a buffering force against a compressive load at the time of a collision of an automobile, wherein the cylindrical FRP is formed from an FRP material that absorbs shock by the collision, and a pressure abutted on the cylindrical FRP It is a method of improving the buffering force by a member,
The end portion of the cylindrical FRP is cleaved by the cleavage induction structure provided in the pressing member, and the cylindrical FRP disperses the compressive load to the load in the fiber direction of the FRP material by the cleaving. A method for improving the shock-absorbing force in which the shock-absorbing force during a car collision is improved.

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