JP2010228337A - Fiber-reinforced plastic structure and connection method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber-reinforced plastic structure having high strength against pullout load, and a connection method for the fiber-reinforced plastic structure. <P>SOLUTION: The fiber-reinforced plastic structure 1 includes a casing member 2 made of fiber-reinforced plastics, and an insert member 4 disposed inside the casing member 2 and connected to a connection member 5 extended from the outside to the inside of the casing member 2 for connection of an external object. The insert member 4 includes a spaced surface 8 formed while being spaced from the casing member 2 and having the connection member 5 connected thereto, and a contact portion 9 formed away from the connection member 5 and making contact with the casing member 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fiber reinforced plastic structure having an insert member therein and a connection method thereof.

  In recent years, resins have been used for weight reduction, for example, in structural members for vehicles, and in particular, fiber reinforced plastics (FRP: Fiber Reinforced Plastics) reinforced with fiber materials have been used. Such FRP molded products are generally attached to other components by adhesion, bolt bonding, or the like. As a method of joining with a bolt or the like, a method of embedding a bolt, a nut or the like as an insert member in the FRP molded product can be cited (for example, see Patent Document 1).

  In the method described in Patent Document 1, an insert member is disposed on the inner side of an FRP outer skin member so as to be in contact with the outer skin member. A hole reaching the insert member from the outside is formed in the outer skin member, and the insert member is in contact with the outer skin member around the hole.

JP 2007-168397 A

  In the method described in Patent Document 1, since the insert member is in contact with the periphery of the hole portion of the outer skin member, when a pulling load is applied to the bolt connected to the insert member, the load is first applied around the hole portion of the outer skin member. Stress is concentrated in the hole. When stress concentrates in the hole, cracks are generated and the crack tends to progress, and the strength may decrease.

  The present invention has been made to solve the problems associated with the above-described prior art, and an object thereof is to provide a fiber-reinforced plastic structure having high strength against a pulling load and a method for connecting the fiber-reinforced plastic structure. And

  A fiber-reinforced plastic structure according to the present invention that achieves the above-described object includes a skin member formed of fiber-reinforced plastic, and a connecting member that is disposed inside the skin member and extends from the outside to the inside of the skin member. A fiber reinforced plastic structure having an insert member coupled to the. The insert member has a separation surface formed separately from the outer skin member and connected to the connection member, and a contact portion formed away from the connection member and in contact with the outer skin member.

  The connection method of a fiber reinforced plastic structure according to the present invention that achieves the above object is a connection method of a fiber reinforced plastic structure in which an insert member is provided inside a skin member formed of fiber reinforced plastic. In the connection method, a connection member extending from the outside to the inside of the outer skin member is connected to a separation surface formed to be separated from the outer skin member of the insert member, and the contact formed away from the connection member of the insert member. The part is brought into contact with the outer skin member.

  In the fiber reinforced plastic structure according to the present invention configured as described above, the insert member is separated from the outer skin member at a separation surface connected to the connection member, and is in contact with the outer skin member at a contact portion formed away from the connection member. For this reason, when a pulling load is applied to the connecting member, stress is not concentrated in a narrow range close to the connecting member of the outer skin member. Thereby, generation | occurrence | production and progress of the crack in the site | part close to the connection member in an outer skin member can be suppressed, and the fiber reinforced plastic structure which has high intensity | strength is realizable.

  The connection method of the fiber reinforced plastic structure according to the present invention configured as described above is performed by connecting the connection member to the separation surface of the insert member, and contacting the contact portion away from the connection member with the outer skin member. When a pulling load is applied to the member, the stress is not concentrated in a narrow range close to the connecting member of the outer skin member. Thereby, generation | occurrence | production and progress of a crack in the site | part close to the connection member in an outer skin member can be suppressed.

It is sectional drawing which shows the FRP structure which concerns on this embodiment. It is sectional drawing which shows before installing an insert member in the manufacturing process of the FRP structure which concerns on this embodiment. It is sectional drawing which shows after installing an insert member in the manufacturing process of the FRP structure which concerns on this embodiment. It is sectional drawing which shows after installing a core member on an insert member in the manufacturing process of the FRP structure which concerns on this embodiment. It is sectional drawing which shows the time of a drawing load acting on the FRP structure which concerns on this embodiment. It is sectional drawing which shows a deformation | transformation of the insert member when a drawing load acts on the FRP structure which concerns on this embodiment. It is sectional drawing which shows the FRP structure of a comparative example. It is a partial expanded sectional view which shows the time of a drawing load acting on the FRP structure of a comparative example. It is a graph which shows the relationship between the displacement at the time of a drawing load acting on an FRP structure, and a load. It is sectional drawing which shows the other example of the FRP structure which concerns on this embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an FRP structure according to the present embodiment, FIG. 2 is a cross-sectional view showing before the insert member is installed in the manufacturing process of the FRP structure according to the present embodiment, and FIG. Sectional drawing which shows after installing an insert member in the manufacturing process of the FRP structure which concerns on a form, FIG. 4 is a cross section which shows after installing a core member on an insert member in the manufacturing process of the FRP structure which concerns on this embodiment FIG.

  As shown in FIG. 1, an FRP structure (fiber reinforced plastic structure) 1 according to the present embodiment includes an outer skin member 2 made of fiber reinforced plastic, a core member 3 and an insert member 4 provided inside the outer skin member 2. And have.

  The outer skin member 2 is formed with a hole 6 for leading a rod-like connection member 5 extending from the outside to the inside of the FRP structure 1 in order to attach an external object.

  The insert member 4 is a member embedded in order to connect the FRP structure 1 to an external object. In the present embodiment, the insert member 4 is a nut having a female screw formed therein. A connecting member 5 having a male screw is screwed into and connected to the insert member 4. The connecting member 5 is not necessarily a separate member from the insert member 4, and may be integrally formed (integrated connection). The shape of the external side (upper side in FIG. 1) of the connection member 5 can be, for example, a female screw or a male screw, but is not particularly limited as long as it is a structure that can connect an external object.

  In the insert member 4, a connecting hole 7 (connecting portion) to which the connecting member 5 is inserted and connected is formed on a separation surface 8 formed to be separated from the outer skin member 2, and formed at a position away from the connecting hole 7. The contact portion 9 is in contact with the outer skin member 2. That is, the separation surface 8 of the insert member 4 has a shape that is recessed in a taper shape from the outer contact portion 9 toward the inner connection hole 7. The contact portion 9 is formed away from the connection member 5 so as to surround the connection member 5, and is formed by an annular surface that contacts the outer skin member 2 within a predetermined range.

  On the surface 11 opposite to the extending direction of the connecting member 5 with respect to the separating surface 8 of the insert member 4, the outer peripheral end centering on the central axis of the connecting member 5 is opposite to the extending direction of the connecting member 5. A projecting portion 10 formed so as to project (toward the opposite surface 11) is formed. The protruding portion 10 is formed to be higher as the distance from the central axis of the connecting member 5 increases.

  As described above, the thickness W of the insert member 4 in the direction in which the connecting member 5 extends is determined by the contact surface 8 and the opposite surface 11 of the insert member 4 being recessed at the center. It decreases from the part 9 toward the connecting member 5.

  The core member 3 is made of a foamed resin, and is filled between the outer skin member 2 and the insert member 4 to play a role of improving strength while suppressing an increase in the weight of the FRP structure 1 as much as possible. The core member 3 is filled between the opposite surface 11 side of the insert member 4 and the outer skin member 2, and the second core is filled between the separation surface 8 side of the insert member 4 and the outer skin member 2. And a core member 3B.

  As the resin applied to the FRP of the outer skin member 2, any resin can be used as long as it becomes a matrix resin of FRP. For example, thermosetting such as epoxy resin, unsaturated polyester resin, vinyl ester resin, phenol resin, etc. Resins, thermoplastic resins such as polyester, polyolefin, and polyamide resin, and mixed resins thereof can also be used.

  The fiber applied to the FRP of the outer skin member 2 is a carbon fiber in the present embodiment, but is not particularly limited as long as it is a reinforcing material. For example, in addition to the carbon fiber, graphite fiber, glass fiber, Examples thereof include organic fibers such as aramid, paraphenylenebenzobisoxazole, polyvinyl alcohol, and polyarylate, or a combination of two or more of these may be used.

  The material of the core member 3 may be, for example, a rigid foam such as polyurethane foam, polystyrene foam, polyethylene foam, polypropylene foam, acrylic foam, vinyl chloride foam, polyimide foam, but is not limited thereto, and wood or the like may be used. it can.

  The insert member 4 is made of aluminum in this embodiment, but for example, a metal material such as steel or titanium is applied in addition to aluminum.

  In order to manufacture the FRP structure 1, first, as shown in FIG. 2, the outer skin member 2 is partially formed, and the first core member 3 </ b> A is formed therein so that the insert member 4 can be inserted. Next, as shown in FIG. 3, the insert member 4 and the connecting member 5 are installed on the first core member 3A. Thereafter, as shown in FIG. 4, the second core member 3 </ b> B is installed or formed on the insert member 4. Thereafter, the upper part of the second core member 3B is covered with a reinforcing fiber base material, and covered with an outer skin member 2 made of a fiber reinforced plastic impregnated with a reinforcing fiber base material and hardened, as shown in FIG. The FRP structure 1 is completed.

  As a method for manufacturing the FRP structure 1, for example, an RTM (Resin Transfer Molding) method can be used, but molding using an autoclave may be used, and the method is not limited.

  Next, the operation of the FRP structure 1 according to this embodiment will be described.

  FIG. 5 is a cross-sectional view showing a case where a pull-out load is applied to the FRP structure according to the present embodiment, and FIG. 6 is a diagram illustrating deformation of the insert member when the pull-out load is applied to the FRP structure according to the present embodiment. It is sectional drawing. FIG. 7 is a cross-sectional view showing an FRP structure of a comparative example, and FIG. 8 is a partially enlarged cross-sectional view showing a case where a pulling load is applied to the FRP structure of the comparative example. FIG. 9 is a graph showing the relationship between displacement and load when a pulling load is applied to the FRP structure.

  When a pull-out load F acts on the connection member 5 connected to the FRP structure 1, the load is transmitted to the contact portion 9 of the insert member 4 that contacts the outer skin member 2 as shown in FIG. A force acts on a portion in contact with the contact portion 9.

Here, in the FRP structure 20 of the comparative example as shown in FIG. 7, the insert member 24 connected to the connection member 25 is provided inside the outer skin member 22 made of fiber reinforced plastic. A surface 27 in contact with the outer skin member 22 is in contact with the entire periphery of the connection member 25. In the FRP structure 20 of this comparative example, as shown in FIG. 8, when a pulling load F acts on the connection member 25, stress is concentrated in the vicinity of the hole portion 26 through which the connection member 25 penetrates in the outer skin member 22. To do. Further, the outer skin member 22, for receiving a strong force as near side of the hole portion 26, shearing force F _X occurs in the vicinity of the hole 26. In the FRP structure 20 of such a comparative example, a crack is easily generated from the vicinity of the hole 26 and progresses, and the strength of the FRP structure 20 is reduced.

  On the other hand, in the FRP structure 1 according to the present embodiment, a force acts on the outer skin member 2 from the contact portion 9 away from the hole portion 6 as shown in FIG. Since the contact portion 9 is formed by an annular surface separated from the hole portion 6, force acts on the outer skin member 2 in a wider area than in the comparative example. Therefore, it is hard to produce a crack and can withstand a higher extraction load F than that of the comparative example.

  FIG. 9 shows experimental results when a pull-out load F is applied to each of the FRP structure 1 of the present embodiment and the FRP structure 20 of the comparative example. As shown in FIG. 9, in the comparative example, when the pulling load F is applied, cracks are first generated at the end portions of the hole portions 26, and the adhesive layer between the insert member 24 and the outer skin member 22 is broken. (Destruction mode 1). When the pulling-out load F is further applied, the outer skin member 2 is deformed on the entire surface 27 of the insert member 4 in contact with the outer skin member 2, and breakage occurs in a wide range of the outer skin member 2 (destruction mode 2). Further, it can be confirmed that when the pull-out load F acts, the destruction progresses and a sudden drop of the pull-out load F occurs.

  On the other hand, in the FRP structure 1 of the present embodiment, when the pulling load F acts, a force acts on the outer skin member 2 from the annular contact portion 9 separated from the hole portion 6, and firstly the insert member 4 and the second core. Although peeling occurs between the members 3B, peeling does not occur on the surface of the outer skin member 2 (destruction mode A). It is confirmed from FIG. 9 that in the region where the failure mode A of this embodiment occurs, the displacement is smaller than that in the failure mode 1 and the failure mode 2 of the comparative example, and a strong pull-out load F can be endured. it can.

  Here, the strength at which the aluminum insert member 4 is deformed is smaller than the bending strength of the skin member 2 made of CFRP (carbon fiber reinforced plastic). Therefore, when a tensile load acts on the insert member 4, the insert member 4 is deformed rather than the outer skin member 2 is bent.

  Further, in the FRP structure 1, the insert member 4 is in contact with the outer skin member 2 at the contact portion 9 away from the connection member 5, so that the load acting on the outer skin member 2 from the insert member 4 is not the in-plane shear direction but the bending direction (Direction in which the outer skin member is bent at the contact portion). At this time, the stress generated in the outer skin member 2 is smaller than the bending strength of CFRP constituting the outer skin member 2. If it is in such a range, even if a stress acts on the outer skin member 2 (CFRP), the bending strength is high and the outer skin member 2 is hardly deformed. Therefore, as the pull-out strength as a whole of the FRP structure 1, the strength at which the insert member 4 is deformed is more dominant than the outer skin member 2, and the same strength as the insert member 4 can be obtained.

  When the pull-out load F acts on the FRP structure 1, the separation surface 8 of the insert member 4 is separated from the outer skin member 2 around the connection member 5, so that the separation surface 8 expands outward as shown in FIG. 6. Deform to Thereby, the contact area of the insert member 4 and the outer skin member 2 increases, and it can bear a stronger load. Note that when the pull-out load F acts and the contact area increases, the positional relationship between the insert member 4 and the outer skin member 2 approaches the positional relationship in the comparative example. Therefore, when the load further increases, the same failure mode 1 and failure mode 2 as in the comparative example can occur in this embodiment, but since the load for deforming the insert member 4 has already been applied, It can withstand a stronger pull-out load F.

  According to this embodiment, the insert member 4 is separated from the outer skin member 2 at the separation surface 8 connected to the connection member 5, and is in contact with the outer skin member 2 at the contact portion 9 formed away from the connection member 5. When the pull-out load F acts on the member 5, it is difficult for stress to concentrate in a narrow range in the vicinity of the connecting member 5 of the outer skin member 2. Thereby, generation | occurrence | production and progress of the crack in the site | part close to the connection member 5 in the outer skin member 2 can be suppressed, and the FRP structure 1 which has high intensity | strength is realizable. Moreover, since stress can be relieved, it is not necessary to provide a reinforcing material between the outer skin member 2 and the insert member 4. However, a configuration in which a reinforcing material is provided is also possible. Further, since the portion where the outer skin member 2 and the insert member 4 are in direct contact is only the contact portion 9, delamination caused by rubbing between the outer skin member 2 and the insert member 4 when vibration is input. Generation can be reduced. Moreover, since the part which the outer skin member 2 and the insert member 4 are directly contacting is only the contact part 9, when the outer skin member 2 and the insert member 4 are materials which mutually energize, there is little area which performs an electrolytic corrosion process. Thus, the manufacturing cost and the number of manufacturing steps can be reduced.

  Further, since the thickness W of the insert member 4 in the extending direction in which the connecting member 5 is extended decreases from the contact portion 9 toward the connecting hole 7, the insert member 4 is easily deformed. Thereby, when the pulling-out load F acts, the separation surface 8 of the insert member 4 expands, and it can suppress that the insert member 4 slips out from the outer skin member 2. In addition, although the connection hole 7 which is a screw hole by the side of the separation surface 8 will expand because the separation surface 8 expands, since the connection hole 7 deform | transforms on the contrary surface side conversely, it is connected. It is possible to suppress slipping of the member 5 from the connection hole 7. In addition, since such an FRP structure 1 can suppress the dropout of the insert member 4 and the connecting member 5 with a single insert member 4, there is no need to increase the number of parts and molding man-hours of the insert member. There is no need to connect the members with high positioning accuracy.

  Further, since the opposite surface 11 of the insert member 4 is formed so as to protrude at a position away from the central axis of the connection hole 7, the connection hole 7 is effective on the opposite surface 11 side when the pull-out load F acts. And the slipping of the connecting member 5 from the connecting hole 7 can be more reliably suppressed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims. For example, the core member 3 may not be provided in the FRP structure 1.

  FIG. 10 is a cross-sectional view showing another example of the FRP structure according to the present embodiment. As described above, the contact portion 32 of the insert member 31 may be provided by another spacer-shaped member. Such a structure can be easily implemented when mainly aiming at stress relaxation of the outer skin member 33. In addition, you may form this insert member 31 and the contact part 32 integrally.

  Moreover, the contact part 9 does not need to be formed in an annular shape, and may be formed, for example, at a plurality of portions. Further, the contact portion 9 is not necessarily in contact with the outer skin member 2 on the surface, and when the rigidity of the outer skin member 2 in contact with the contact portion 9 is sufficiently high, or when another reinforcing material is provided between the outer skin member 2 and the like. Alternatively, point contact can be used.

1 Fiber reinforced plastic structure (FRP structure),
2,33 skin member,
3 core members,
3A 1st core member,
3B second core member,
4,31 insert member,
5 connecting members,
6 holes,
7 connection hole (connection part),
8 Separation surface,
9,32 contact part,
10 protrusion,
11 Opposite side,
F Pull-out load,
W The thickness of the insert member.

Claims (4)

A skin member formed of fiber-reinforced plastic;
A fiber reinforced plastic structure having an insert member disposed inside the outer skin member and connected to a connecting member extending from the outside to the inside of the outer skin member,
The insert member is a fiber reinforced plastic structure having a separation surface formed to be separated from the outer skin member and connected to the connection member, and a contact portion formed away from the connection member and in contact with the outer skin member. body.   The fiber reinforced plastic structure according to claim 1, wherein a thickness of the insert member in an extending direction in which the connecting member is extended decreases from the contact portion toward a connecting portion to which the connecting member is connected. body.   The connecting portion is a connecting hole to which the connecting member is inserted and connected, and the surface opposite to the extending direction of the insert member is opposite to the extending direction at a position away from the central axis of the connecting hole. The fiber-reinforced plastic structure according to claim 1, wherein the fiber-reinforced plastic structure is formed to protrude in the direction. A method for connecting a fiber reinforced plastic structure in which an insert member is provided inside a skin member formed of fiber reinforced plastic,
A connecting member extending from the outside to the inside of the outer skin member is connected to a separation surface formed away from the outer skin member of the insert member, and is formed apart from the connecting member of the insert member. A method for connecting a fiber reinforced plastic structure, wherein the contact portion is brought into contact with the outer skin member.

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