JP2002294877A - Frp joining structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FRP joining structure 25 having strength and rigidity equal to or more than an integral mold by adopting a joining method 8 excellent in strength and rigidity when joining mutual FRP members 1 being a main constitutive member of the FRP structure 25. SOLUTION: A structure joins a plurality of FRP members 1 via a joining member 8. This FRP joining structure 25 is characterized in that the joining member has a part arranged so as to run along both or one surface of upper and under surfaces of the FRP members 1, and the length L2 of this part is set 0.8 to 3 times the thickness H1 of an FRP member cross section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FRP joining structure, and more particularly, to joining a plurality of FRP members,
The present invention relates to an FRP bonded structure using a bonding method capable of forming a large structure.

[0002]

2. Description of the Related Art Conventionally, iron, which is often used as a structural material,
FRP (fiber reinforced resin), which is lighter than aluminum alloy, has been applied in various fields. Particularly, among FRP, CFRP using carbon fiber having excellent specific strength and specific rigidity.
(Carbon fiber reinforced resin) has received much attention.

[0003] The CFR has the characteristics of being light and strong.
As is well known, the advantage of P material is that the weight of parts is greatly reduced as compared with other materials, and particularly when used as transportation equipment and rotating equipment, the energy efficiency is improved, and building materials and the like are improved. When applied to a structure, the degree of freedom of design can be expanded and safety such as earthquake resistance and weather resistance can be greatly contributed.

[0004] Taking advantage of the above-mentioned advantages, FRP molded products have been developed for various uses in addition to large-sized structural materials.

However, manufacturing a large-sized and complicated product by integral molding is inefficient because of an increase in manufacturing cost and equipment. Therefore, when manufacturing these complicated structures and large objects, it is necessary to first form some divided members and then join these divided members to finally obtain the intended structure. This requires an assembly and joining technique for a large molded product, and this technique is also an important technique for integrating and joining the FRP member and other members.

Conventionally, as a method of joining the FRP members, a method using a fastening member such as a bolt and a pin, and a method using adhesion or the like are well known. However, in joining with bolts, pins, and the like, it is necessary to provide a through hole in the FRP member. However, this method not only reduces the strength of the FRP member, but also reduces the stress transmission of the joint by bolts and pins.
Since the pin and the through hole are provided, the FRP member, the bolt, and the pin are supported by the surface pressure strength and the shear strength. Therefore, the bonding strength developed per bolt or pin is relatively small, and in order to obtain higher strength, it is necessary to increase the diameter or increase the number of bolts, pins, and the like.
These methods increase the labor and cost of joining. In addition to bolts, pins, etc., bonding by bonding and a bonding method using both bolts and pins are well known. However, in the case of bonding, there are many cases in which the bonding agent is deteriorated due to long-term use, and the bonding strength varies due to uneven coating, and it is often difficult to ensure the reliability.

[0007] For example, as a joining method other than the above-mentioned bolt, pin, and bonding, in Japanese Patent Application Laid-Open No. 2000-336777, a joining member mainly made of a metal material is buried inside an FRP member and joined via the joining member. Discloses a method for forming an FRP bonded structure. This method uses F
In this method, a joining member is provided on the RP member, and the FRP member is joined via the joining member.

[0008] However, in this method, there is no clear position and stipulation of the location installed inside the FRP member.
Therefore, depending on the shape of the joining member provided inside the FRP member, the case where stress concentration occurs inside the member or the effect of the increase in weight due to the addition of the joining member increases, and the weight of the FRP structure increases as a whole, and the weight is reduced. May be lost. Further, the above publication does not disclose any method for treating the surface of the joining member embedded in the FRP member. If the surface of the joining member is not properly treated, an appropriate bonding state between the FRP member and the joining member may not be obtained, and sufficient adhesive strength may not be obtained. In addition, for example, when an FRP member is molded and cured, an acidic curing agent is used, and when the corrosion resistance of the joint member is low, corrosion of the joint member and uncuring of the resin are liable to occur.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an FR
In joining the P members, by using a joining method that is excellent in strength and rigidity, the strength, which is equal to or higher than that of the integrally molded product,
An object of the present invention is to provide a rigid FRP joint structure.

[0010]

Means for Solving the Problems In order to solve the above problems, the FRP joint structure of the present invention has the following two structures.

That is, an FRP joining structure in which a plurality of FRP members are integrally joined via a joining member, wherein the joining member is integrally formed with the FRP member, and is formed on both upper and lower surfaces or one surface of the FRP member. It has an attached portion, and includes the cross-sections of the upper surface, the lower surface, and the end surface of the FRP member, and in a cross section parallel to the length direction of the FRP member, the length of the attached portion. Sa (L
2) The FRP joined structure, wherein the thickness (H1) of the FRP member is 0.8 times or more and 3 times or less.

An FRP joining structure in which a plurality of FRP members are integrally joined via a joining member, wherein the joining member has a portion integrally formed with the FRP member, and A joint member integrally formed with the joint member is covered with a material different from that of the joint member.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a joint portion of an FRP joint structure 25 of the present invention, and shows an integrated state in which a pair of left and right FRP members 1 are joined by a joint member 6 at a central portion. In this embodiment, each of the FRP members 1 has a so-called sandwich structure in which an FRP layer upper surface 3 and an FRP layer lower surface 4 made of FRP are disposed on both surfaces of a core material 2. The constituent material of the FRP is not particularly limited, but the reinforcing fiber is made of carbon fiber or glass fiber, and the matrix resin is made of epoxy resin, vinyl ester resin, unsaturated polyester resin, phenol resin or the like.

The pair of left and right joining members 6 have the shape shown in FIG. That is, FIG. 2 is a perspective view of the joining member 6 shown in FIG. 1, and the whole is made of a structural material such as general structural steel, stainless steel, etc., of which the FRP layer upper surface 3, the FRP layer lower surface 4, and the FRP layer The buried portion 7 surrounded and buried by the layer end surface 5 and the FRP layer back surface 23 has a U-shaped cross-sectional shape, and is integrally formed with the FRP member 1.
The cross section of the buried portion 7 in the FRP cross section which includes the cross section of the FRP member upper surface, the lower surface, and the end surface in the RP layer upper surface 3 and the FRP layer lower surface 4 and is parallel to the length direction of the FRP member which is the left-right direction in FIG. A portion having a length L2 is provided. In the FRP member 1, the portion having the cross-sectional length L2 is FR
It serves to transmit the stress from the P member 1 to the joining member 6, and the dimensions of the cross-sectional length affect the bending strength, the compressive strength, and the like of the joining structure 25. Further, the embedded portion 7 is provided with a coating layer 24 of a material different from that of the joining member 6. Further, the joining member 6 is formed by projecting from the FRP layer end face 5 to the outside of the FRP member 1 with a part of the joining member 6 being formed on a flat plate to connect the pair of left and right joining members 6 to each other. 8 As an example of the joining of the FRP members 1, for example, FIG.
As shown in the figure, the FRP members 1 having the length L1, the width W1, and the thickness H1 are arranged to face each other, these projections 8 are sandwiched by the joint attachment plate 9, and the bolts 10 are passed through the projections 8, When they are joined to each other, the FRP joint structure 25 shown in FIG. 3 in which the total length is twice the length L1, the width is W1, and the thickness is H1 is completed.

In this embodiment, the FRP members 1 are joined to each other. However, other than that, for example, a support or a support wall for supporting the FRP member is provided on the surface of the structure, and similar to the projecting portion 8 of the joining member. If these members are provided and joined together, a structure such as a cantilever can be formed. In addition, the joining member 6 is arranged at an appropriate position on the FRP member 1,
By continuously joining a plurality of FRP members by a method such as providing a protrusion 8 as described above and bolting or welding, or providing a thread in the buried portion 7 and bolting, various shapes and sizes are provided. Is possible.

Regarding the cross-sectional shape of the buried portion 7 of the joining member 6, the thickness of the FRP member is H1, and the cross-sectional length of the buried portion is L2.
Then, it is desirable that the value of the ratio L2 / H1 be 0.8 or more and 3 or less. The reason is that the ratio L2 / H1 is 0.
If it is less than 8, the sectional length L2 of the buried portion 7 where stress transmission occurs
Becomes insufficient, the stress concentration generated in the buried portion 7 of the joining member 6 and the FRP layer becomes too strong, and if it exceeds 3, the weight of the joining member 6 increases and the lightness of the structure is impaired. This is because the load on the FRP member 1 due to the weight of the joining member 6 itself increases in some cases. The ratio is more desirably 0.85 to 2. This makes the joining member 6 simple and lightweight under conditions that optimize the balance between the strength, rigidity and weight of the joining structure, and reduces the overall manufacturing cost of the FRP member 1 and the joining member 6. Because.

The joining member 6 may be installed at any position inside the FRP member.
When joining the P member 1, the joining member 6 is provided so as to be in contact with the end portion 5 of the FRP member.
Of the joining member H2 so as to make contact with the FRP member 1.
It is desirable to set the joint member 6 and the FRP member 1 so that they are the same as the inner surface of the P layer so that the joint member 6 and the FRP member 1 are in contact with each other on three surfaces. This is FRP
This is for optimizing the stress transmission between the member 1 and the joining member 6. In particular, in the case of the present embodiment, the embedded portion 7 of the joining member 6 is provided at the FRP member end 5 at the upper surface 3 of the FRP layer 1 of the FRP member 1. The stress transmission between the FRP member 1 and the joining member 6 is performed in a wide area by installing the FRP layer end surface 5 and the FRP layer lower surface 4 so as to achieve higher strength joining.

More preferably, it is desirable that the FRP layer is provided over the entire surface of the buried portion 7 integrally formed. This is because the stress transmission area between the FRP layer and the buried portion 7 is increased as described above, and the entire circumference is in contact with the FRP layer so that it can cope with loads in all directions. In the present embodiment, the joining member 6 is provided so as to follow the upper surface 3, the end surface 5, and the lower surface 4 of the FRP layer.
Are arranged, the joining member 1 and the FR
The P member 6 can be deformed by applying a load,
A stronger bond results.

When the joining member 6 is made of a corrosive material such as a rolled steel material for general structure and the resin matrix of the FRP member 1 uses an acidic hardener, the resin is If the buried portion 7 is directly touched, the buried portion 7 may be corroded and the resin may be uncured. Therefore, in such a case, by covering the buried portion 7 with a material having corrosion resistance by the method described above, it is possible to prevent resin curing failure around the buried portion 7 and to prevent corrosion of the joining member 6,
Excellent joints are obtained.

As the matrix material of the upper surface 3 and the lower surface 4 of the FRP layer covering the buried portion 7, in addition to the matrix resin constituting the FRP, ceramics, various metals such as nickel and chromium, and compounds thereof are considered. But
In order to reduce the cost of the coating material, it is desirable that the resin be a resin.
Taking into account the familiarity with the P member, it is desirable to use an unsaturated polyester resin, vinyl ester resin, epoxy resin or phenol resin.

The coating method includes various kinds of coating, thermal spraying,
Plating, thin film surface treatment by PVD and CVD, etc. are conceivable, but those with resin coating finish provide high adhesion between the FRP member 1 and the joining member 6, the coating layer 24 and the joining member 6, and are easy to coat. Desirable.

It is desirable that the FRP member 1 has a sandwich structure. This is for reducing the weight and increasing the rigidity of the FRP member 1. An FRP layer for controlling the strength and rigidity is disposed on the surface layer of the FRP member 1, and a light-weight material such as a resin foam or a honeycomb core is formed inside the core material. By arranging the two, optimization as a lightweight and highly rigid structure is achieved.

The joining method shown in FIG. 4 is an example of another embodiment of the present invention. The FRP member 13 has a sandwich structure in which an FRP layer upper surface 15 and an FRP layer lower surface 16 are disposed on a core 14, and a joining member 18 is provided on the FRP member 13. The embedded portion 19 of the joining member 18 inside the FRP member 13 has an L-shaped cross section, and is attached to the lower surface of the FRP member with a length L2. The embedded portion 19 of the joining member 13 is installed at the end of the FRP member so as to be in contact with the end face 17 of the FRP member, and the projection 20 is exposed outside the FRP member. The FRP members 18 are joined together by fastening the projecting portions 20 of the joining members 13 through the bolts 22 through the joint attachment plates 21.
In this embodiment, the buried portion 19 is provided only on the lower surface 16 side of the FRP layer, and cannot support a large load with respect to a load from below to above the paper surface.
By setting / H1 to be 0.8 or more and 3 or less, a strong joining structure can be obtained with respect to a load from above to below the sheet. When the load direction is constant as described above, the length L2 of the buried portion 19 of the joint member 6 installed along the FRP member 13 can be installed on one side, and an appropriate joint member 6 for the load to be carried can be provided. By designing, it is possible to further simplify the configuration of the joint and reduce the weight.

[0024]

The embodiments of the present invention and the effects thereof will be specifically described below. (Embodiment 1) Using the structure of the FRP member 1 and the bonding member 6 shown in FIGS. A test body to be the body 26 was manufactured. The joining member 1 has the shape shown in FIG. 2, and in this embodiment, L2 is 0.25 m. Therefore, the ratio L2 / H of the joining portion length L2 to the specimen thickness H1 is used.
1 is 0.96. The buried portion 7 of the joining member 6 was spray-coated with a vinyl ester resin to form a coating layer 24 having a thickness of about 1 mm. As shown in FIG. 3, the fulcrum 12 is arranged so that the support span L is 4.5 m, and the indenter 11 is pressed down from above to the center thereof, and the joint structure is obtained by a so-called three-point bending fracture test. Twenty-five strengths were measured. In the test, a load was applied to the specimen by moving the indenter at a speed of 2 mm per second. Under the above test conditions, a load which is a proportional limit of a load applied by the indenter and a stroke was measured, and this was defined as a breaking strength. Table 1 shows the test results. (Embodiment 2) The structure is the same as that of Embodiment 1, and the sectional length L2
Was set to 0.42 m. Therefore, the ratio L2 / H1 is 1.6.
2. Other test methods are the same as in Example 1.
Table 1 shows the test results. (Comparative Example 1) The same configuration as in Example 1 was used, and the length L2 was set to 0.01. Therefore, the ratio L2 / H1 is 0.04
The other test methods are the same as in Example 1. Table 1 shows the test results. (Comparative Example 2) The same configuration as in Example 1 was used, and the length L2 was set to 0.09 m. Therefore, the ratio L2 / H1 is 0.35
The other test methods are the same as those in the first embodiment. Table 1 shows the test results. (Comparative Example 3) For comparison of strength with the joint structure 25, FIG.
(L1 = 2.4 m, W1 =
1.2 m, H1 = 0.26) and an integrally formed blank plate without a joining member were prototyped, and the test was performed in the same manner. Table 1 shows the test results.

From the test results shown in Table 1, the breaking strength of Example 1 was 12 tons, and the breaking strength of Example 2 was 15 tons. The bonding member 1, the end face 5 of the FRP layer, the rear face 23 of the FRP layer, It can be seen that the strength is superior to the breaking strength of 10.5 ton of Comparative Example 3 having neither the attachment plate 9 nor the bolt 10. The breaking strengths of Comparative Examples 1 and 2 are 0.8 ton and 6.0 ton, respectively, which are weaker and inferior to Comparative Example 3. Based on these results, a graph in which the horizontal axis represents the ratio L2 / H1 and the vertical axis represents the breaking strength is as shown in FIG. As can be seen from FIG. 5, the ratio L2
/ H1 is about 0.8, and the same strength as Comparative Example 3 having no joint is developed, indicating that good joint strength is obtained.

[0026]

[Table 1]

[0027]

The FRP joint structure of the present invention has, at the joint portion of the structure, a portion in which the joining member is provided along both or one of the upper and lower surfaces of the FRP member. Since the length in the cross section of the FRP member including the upper and lower surfaces and the end surface of the FRP member and parallel to the length direction of the FRP member is set to be not less than 0.8 times and not more than 3 times the thickness of the cross section of the FRP member. When members are integrally joined, an FRP joint structure excellent in both strength and rigidity can be configured. Therefore, the present invention can be applied to the construction of a large building or the like, and an FRP joined structure excellent in structural strength and rigidity can be obtained in combination with the high elasticity and light weight of FRP.

Further, the FRP bonded structure of the present invention is an FRP bonded structure.
Since the portion of the joining member integrally formed with the member is covered with a material different from the joining member, the FRP joining structure having excellent adhesiveness between the joining member, the coating layer, and the joining member, and having a more excellent structure. In addition, when the joining member has poor corrosion resistance and the matrix resin of the FRP member uses an acidic curing agent, corrosion of the joining member due to the acidic curing agent can be prevented. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a joint of an FRP joint structure of the present invention.

FIG. 2 is a perspective view of a bonding member used in the FRP bonding structure of FIG.

FIG. 3 is a perspective view showing a method of a fracture strength test of the FRP joint structure of FIG.

FIG. 4 illustrates an embodiment of the present invention F different from the structure of FIG.
It is a RP structure longitudinal sectional view.

FIG. 5 is a diagram in which the horizontal axis is L2 / H1, and the vertical axis is the breaking load, to show the breaking strength of the example and the comparative example.

[Explanation of symbols]

 1, 13 ... FRP member 2, 14 ... Core material 3, 15 ... FRP layer upper surface 4, 16 ... FRP layer lower surface 5, 17 ... FRP layer end surface 6, 18 ... Joining Member 7, 19 ... Embedded part 8, 20 ... Projection part 9, 21 ... Additional plate for joining 10, 22 ... Bolt 11 ... Indenter 12 ... Support point 23 ... FRP Layer back 24 ・ ・ ・ Coating layer 25 ・ ・ ・ Joining structure L ・ ・ ・ Test span length L1 ・ ・ ・ Specimen length H1 ・ ・ ・ Specimen height W ・ ・ ・ Specimen width L2 ・ ・ ・ Embedded part Section length H2 ・ ・ ・ Section height of buried part

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2E125 AA76 AF03 AF04 AF07 AG12 AG41 AG58 BB09 BB22 BB35 BD01 BE07 BE08 BF04 CA05 4F211 AD03 AD19 AG23 AH46 TA06 TC09 TD07 TH02 TH18 TH20 TJ22 TN76 TN77

Claims (8)

[Claims] An FRP joining structure in which a plurality of FRP members are integrally joined via a joining member, wherein the joining member is integrally formed with the FRP member, and
It has a portion attached to both upper and lower surfaces or one surface of the member, and includes the cross-sections of the upper surface, the lower surface, and the end surface of the FRP member, and in the cross-section parallel to the longitudinal direction of the FRP member, The length (L2) of the installed part is FRP
An FRP joined structure, wherein the thickness is not less than 0.8 times and not more than 3 times the thickness (H1) of the member. 2. The FRP joint structure according to claim 1, wherein the joint member is provided at an end of the FRP member. 3. The FRP joint structure according to claim 1, wherein a portion of the joint member integrally formed with the FRP member is covered with an FRP layer. 4. An FRP joining structure in which a plurality of FRP members are joined together via a joining member, wherein the joining member has a portion formed integrally with the FRP member, and A joint member integrally formed with the joint member is covered with a material different from the joint member. 5. The method according to claim 1, wherein the FRP member is formed of a resin matrix which is hardened by an acid hardener, has a portion directly in contact with a portion of the joining member integrally formed with the FRP member, and the joining member is made of a metal material. The FRP joined structure according to claim 4, characterized in that: 6. The FRP joint structure according to claim 4, wherein a portion of the joint member integrally formed with the FRP member is covered with a synthetic resin. 7. The FRP according to claim 6, wherein the synthetic resin is any one of an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, and a phenol resin.
Joint structure. 8. The FRP member has a sandwich structure in which FRP layers are provided on both surfaces of a core material.
The FRP bonded structure according to any one of the above.