JPS5871119A - Preparation of joint made of tubular compound material - Google Patents

Abstract

PURPOSE:To obtain a joint of light weight and high strength by such an arrangement wherein adhesive is applied to the stepped surfaces of a stepped joint member, is prehardened, and said joint members are set on a mandrel for forming, and layers of compound forming material are laminated on said mandrel and joint members and are heat treated. CONSTITUTION:Adhesive in the form of film 2 is applied to the surface of stepped portions of a joint member 1, and dried, and the thickness of the adhesive layer is caused to maintain by pre-hardening said adhesive 2. Next, said joint member 1 is mounted on a mandrel 3 which has been treated with a mold release agent and layes of compound forming material 4 are wrapped around the mandrel and laminated. After that the layers with the mandrel 3 installed are hardened by heating with pressure applied. Conditions of pressurization and heating are determined by the condition of hardening of the resin of the compound forming basic material 4. Upon completion of said hardening, the mandrel is extracted and a final product can be obtained. By this method, a joint of light weight and high strength can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of making a high strength joint of tubular composite material.

There is not much prior art related to this type of technology, but
Figure 1 and Table 1 outline the conventional one-manufacturing method used for composite materials (referring to reinforced resin molding materials such as carbon fiber/epoxy resin) and its drawbacks. show.

/'/' / / 7/ , / / / / / / On the other hand, with the development of aerospace equipment, the development of composite materials molded into tubes as structural members has led to the development of lightweight, high-stress, fully effective materials. There is a need to develop a joint that can transmit information.

Therefore, the present invention provides a method for manufacturing a lightweight, high-strength, tubular composite material joint that eliminates the drawbacks shown in Table 1.

That is, the present invention provides a method for manufacturing a joint made of a tubular composite material, in which a gold adhesive is applied to the step surface of a stepped joint member, the adhesive is fully precured, and then the entire stepped joint member is coated on a molding mandrel. After setting and laminating the composite material molding material on the mandrel joint member,
The present invention relates to a method for manufacturing a joint of a tubular composite material, characterized in that heat treatment 7 is performed to simultaneously harden the molded material and join it to the joint member.

In the present invention, a joint member processed into a step-like shape is used, and various materials can be used for the member depending on the application, but especially when light weight and high strength are required, 1 alloy is used. (having a small coefficient of thermal expansion) is best; alloys with aluminum have a large coefficient of thermal expansion, and steel is disadvantageous in terms of weight.

In addition, in the present invention, the composite material molding material (all prepreg before hardening) is wrapped and laminated into a tube shape, and then heat-treated and cured, and at the same time, all the joining to the above-mentioned joint member is performed. The adhesive used is one that is compatible with the composite molding material, and in order to prevent fiber bending, which is one of the weak points of composite materials at the joint, the thickness of the adhesive is the same as that of the molding material after full molding. It is important to set the adhesive layer to a thickness equivalent to one layer, and in order to maintain this adhesive layer thickness, all of the adhesive is pre-cured under appropriate conditions.

As a result of the above, a joint that is lightweight, has high strength, and has excellent moldability can be obtained.

The present invention can be applied to all products using tubular composite materials having joint members, such as (1) structural members for aerospace equipment, (2) structural members for general industrial equipment, and (3) sporting goods.

Hereinafter, the method of the present invention will be explained in detail with reference to all the accompanying drawings.

FIG. 2 is a diagram showing a practical example of the method of the present invention.

First, all pretreatments of the multi-step joint member 1 shown in FIG. 2(m) are performed. Preferably, the pretreatment is a chemical treatment method that takes into account adhesive properties.

In the second step (B), a film adhesive 2 is applied to the step surface of the joint member 1, and after drying, the adhesive 2 is fully precured to maintain the adhesive layer thickness. This preliminary curing is carried out to make the thickness of the adhesive layer uniform, and is carried out under heating and pressurizing conditions within a range that does not interfere with the final curing in the next step [FIG. 2(C)]. For example, the heating temperature should be set to a minimum temperature of 80°C or higher at which the adhesive flows, and a maximum temperature of 125°C or lower, which is necessary to slow down the crosslinking reaction rate, and the pressure is set to the minimum pressure necessary to obtain a uniform thickness and edges. 5 An upper limit pressure cuff that does not make the adhesive layer thickness too thin when the pressure is 1 ps or more. It is preferably 0 psi or less. Next, the above-mentioned joint member 1 is subjected to a mold release treatment as shown in FIG. 2 (0) (a). Composite material molding material 4'f! is attached to the finished mandrel 5, and a molding material wrapping device (not shown) is used to wrap the composite material molding material 4'f! :
It is wound and laminated as shown in FIG. 2(0)(b).

The number of laminated layers is determined by the thickness of the composite material of the final product.

Note that the number of steps of the joint member 1 is similarly determined by the thickness of the composite material of the final product.

Determined by curing conditions. Note that as a means for heating and pressurizing, for example, an autoclave or the like is used.

When the above-mentioned curing is completed, the mandrel is decoreted five times to obtain the final product shown in FIG. 2(D).

As described above, by wrapping the composite material molding material 4 around the joint member 1 and bonding to the member 1 at the same time as the material hardens, the bonding surfaces of the joint member 1 and the composite material molding material 4 are bonded. In addition to improving the strength, it is possible to completely prevent stress concentration due to multi-stage steps, and to obtain a joint that is stronger, lighter, and stronger than conventional joints.

Furthermore, in the method of the present invention, it is also possible to use a joint member 1 which has been step-processed on both sides as shown in FIG. 3, and when this joint member 11r is used, the same method as in the case of FIG. 2 is applied.

The effects of the method of the present invention explained above are summarized in Table 2〇, /'' // Table 2 Effects of the method of the present invention Furthermore, the conventional joint manufacturing method can be rounded to obtain the same strength as the joint made by the method of the present invention. In the case of secondary adhesive bonding method, it is required to be 2 to 3 times the diameter and 2 to 5 times in weight, and in the case of fastener bonding method, it is required to be approximately twice the thickness of the composite material and 1" in weight. It has been confirmed that approximately 1.4 times the amount is required.

Next, examples of the present invention will be given.

Example 1 All joints of the type shown in Fig. 5 were manufactured.

After applying an epoxy film adhesive to a thickness of 25 m as an adhesive on the step surface of the Ti joint member 1, 12
Precure for 90 minutes at 0°C and 3 to 7 psi, then set on a molding mandrel and use carbon/epoxy resin prepreg (resin gold 841%) as a composite molding material.
, volatile content 1.4%) r winding is laminated (13 layers) 1~
Thereafter, final curing was performed at 177° C. and 95 psi for 2 hours. Compression and tensile tests were conducted on the joints obtained as described above. The results are shown in Table 3. Test Results Reference Example 1 (Example to show the effect of precuring) All joints of the type shown in FIG. 6 (m) were manufactured.

In Fig. 6 (m), 1 is a flat plate (stepped? Not processed) Ti joint member with a thickness of 2 mm, and 4
This is a composite material obtained using all the same composite material molding materials as in Example 1.

The manufacturing method for this joint is as follows: After surface treatment of the Ti joint member 1, the same adhesive as in Example 1 is applied, and the temperature is 120°C for 3 to 7 hours.
After pre-curing at psi for 40 minutes, the composite material was wrapped and laminated at 177°C in an autoclave.
Two types of curing were performed: one was final curing at 95° C. for 2 hours, and the other was the same as above except that no preliminary curing was performed.

When the tensile shear strength of the obtained joint was completely measured, the results shown in FIG. 6(B) were obtained.

As is clear from FIG. 6(B), it can be seen that the tensile shear strength of the specimens that were fully precured was significantly improved compared to those that were not precured.

Reference Example 2 (Example for demonstrating the effect of simultaneous adhesion) A joint of the type shown in FIG. 7 (m) was manufactured. The materials and dimensions in FIG. 7(M) are the same as those in FIG. 6(A) of Example 1, but the manufacturing methods are simultaneous bonding by the method of the present invention and secondary bonding by the conventional method (molding of composite material = 177° C., 95 psi, 2 hours, contact with joint member 5111: 177° C., 50 psi, 1 hour) was used.

All tensile shear strengths were measured for these joints. The results are shown in FIG. 7(B).

As is clear from FIG. 7), it can be seen that the tensile shear strength of the nine cases in which simultaneous adhesion was performed was significantly improved compared to the case in which all secondary adhesion was performed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an overview of a conventional joint manufacturing method, FIG. 2 is a diagram showing an embodiment of the method of the present invention, FIG. 3 is a diagram showing another joint member used in the method of the present invention, and FIG. Figure 4 is the ninth diagram to explain the concentrated relaxation of new ground force, which is one of the effects of the method of the present invention, Figure 5 is a diagram showing the shape of the tomo joint manufactured in Example 1 of the present invention, and Figure 6 Are the shape of the joint manufactured in Reference Example 1 of the present invention and the measurement results of the tensile shear strength of the joint? The figure shown in FIG. 7 is a diagram showing the shape of a friend joint manufactured in Reference Example 2 of the present invention and the measurement results of the tensile shear strength of the joint. Sub-agents 1) Meikoku agent Ryo Hagiwara - Figure 1 (A) (B') (C) Ma 6 (β) (A) Atsushi 7 (8) (A)

Claims (1)

[Claims] In a method for manufacturing a joint of a tubular composite material, after applying an adhesive to the entire step surface of a step-like joint member, the adhesive is pre-cured, and then set in a mold/drel for molding the entire step-like joint member; Fabrication of a tube-shaped composite material joint by applying heat treatment to simultaneously harden the molding material and bonding it to the joint member at the same time after laminating the entire wrap of the composite material molding material on the mandrel and the joint member. Method.