A method and apparatus for testing the friction of a rectangular mold cavity against a preform under compression

Abstract

The application discloses a method and device for testing friction between a rectangular mold cavity and a preform under compression. The preform is often washed away during resin filling of an RTM process. The application provides a method and device for testing friction between a rectangular mold cavity and a preform under compression, which can be used to test the compression friction between a layer fabric and the mold cavity. The device is connected to a universal testing machine through a connecting piece, and the centering problem is solved. A push head is installed above the universal testing machine, and the compression is controlled by lifting the universal testing machine. Finally, the required compression friction is measured. The method is simple and easy to understand. The device is easy to operate, and is beneficial to improving production efficiency and reducing production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical fields of testing machines, composite materials, composite material testing, machining, clamps and the like, and particularly relates to a method and device for testing the friction between a rectangular mold cavity and a preform under compression. BACKGROUND

[0002] Composite materials are widely used in aerospace, aviation, shipping and other industries due to their high strength, high modulus and strong designability. The production and preparation of composite materials have become extremely important as the demand for composite materials has grown, especially the regulation of process parameters during the production and preparation of composite materials. In the process of preparing composite laminates, especially in the process dominated by liquid molding, the interaction of force between the mold and the fabric determines the regulation of process parameters during the preparation.

[0003] Currently, there is no specific device to test the actual interaction force between the mold and the preform, especially the compression friction between the mold and the preform. Most experiments in the research process use numerical simulation methods, but the error between numerical simulation and actual compression friction is large, resulting in some deviations in guiding the actual production process. SUMMARY

[0004] To address the problem of low production efficiency and increased production cost due to the improper regulation of process parameters in the existing process of making flat composite materials, the present application aims to solve the above technical problems and proposes a method and device for testing the friction between a rectangular mold cavity and a preform under compression. The device is connected to the universal testing machine through the connecting piece, and the centering problem is solved. The compression member is installed on the upper part of the testing machine, and the lifting of the testing machine controls the lifting of the compression member. Finally, the required compression friction is measured. The method is simple and easy to understand, and the device is easy to operate, which helps to improve production efficiency and reduce production cost.

[0005] To achieve the above purpose, the technical solution provided by the present application is a method and device for testing the friction between a rectangular mold cavity and a preform under compression. The device is connected to the universal testing machine through the connecting piece, and the centering problem is solved. The compression member is installed on the upper part of the testing machine, and the lifting of the testing machine controls the lifting of the compression member. Finally, the required compression friction is measured.

[0006] The compression member is connected to the testing machine through the cylindrical upper end, and the lower end of the compression member is a T-shaped piece. The upper part of the T-shaped piece is the main component for bearing pressure, and the lower compression plate is the main test end.

[0007] The length, width and thickness of the compression member are all smaller than those of the mold cavity by about 1mm to eliminate the friction between the compression member and the mold cavity.

[0008] The mold and the base are connected through threaded holes, and the threaded holes of the mold are located on the upper and lower mold plates.

[0009] The base is divided into a flat plate and a cylindrical pin, and the center of the pin on the flat plate should coincide with the center of the mold cavity, and the flat plate has four threaded holes corresponding to the mold.

[0010] During testing, the compression member is first lowered into the empty mold cavity, and if the friction force at this time is zero, the mold and the testing machine are connected, and then the edge of the fabric in the mold cavity is flush with the edge of the mold cavity during testing.

[0011] Compared with the prior art, the method and device for testing the friction between the rectangular mold cavity and the preform under compression conditions have the advantages that the method is scientific and reasonable, the universal mechanical testing machine is used to connect the testing machine and the mold through the connecting member, then the compression member is inserted into the mold cavity, the fabric is compressed downward, the force during compression is transmitted by the universal testing machine, and the compression friction force is obtained, the method is simple and easy to understand, the device is easy to operate and has strong controllability, and the production cost is reduced and the production efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a schematic view of the overall structure of the method and device for testing the friction between the rectangular mold cavity and the preform under compression conditions.

[0013] Figure 2 It is a schematic view of the structure of the compression member.

[0014] Figure 3 It is a schematic view of the structure of the mold.

[0015] Figure 4 It is a schematic view of the structure of the base.

[0016] Reference signs in the drawings:

[0017] In the drawings: 1 compression member, 2 mold, 3 base connecting member, 4 connecting cylinder, 5 groove, 6 stop plate, 7 push plate, 8 threaded hole, 9 flat plate, 10 pin hole, 11 pin. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the application will be described in detail below with reference to the drawings in the embodiments of the application. The embodiments are only some of the embodiments of the application, not all the embodiments.

[0019] As Figure 1As shown, a method and device for testing the friction between a rectangular die cavity and a preform under compression conditions include a compression member 1, a die 2, and a base connecting member 3. The die 1 is connected to a universal testing machine through the base connecting member 3 and is centered on the central axis. The compression member 1 is installed above the testing machine, and the compression member 1 is raised and lowered by the lifting of the testing machine. The compression friction force is finally measured.

[0020] As shown in Figure 2 The compression member 1 is connected to the testing machine through a connecting cylinder 4 at the upper end. The connecting cylinder 4 at the upper end has a groove 5, and the groove 5 is fixed to the testing machine by screws. The lower end of the compression member is a T-shaped member. The upper part of the T-shaped member is a pressure-bearing stop plate 6, and the lower compression plate is the main test push plate 7. When the testing machine moves downward, the push plate 7 extends into the die cavity, and the bottom surface of the push plate 7 contacts the cross section of the fabric, pushing the fabric downward. When the experiment is completed, the testing machine moves upward, and the screws in the groove 5 bear the main force, lifting the compression member 1 from the inside of the die cavity. The length, width, and thickness of the compression member 1 are all about 1 mm smaller than those of the die cavity, so as to eliminate the friction between the compression member and the die cavity.

[0021] As shown in Figure 3 The die 2 is connected to the base through the threaded holes 8. The threaded holes 8 of the die 2 are located on the upper and lower die plates.

[0022] As shown in Figure 4 The base connecting member 3 is shown in the structural diagram. It is divided into a flat plate 9 and a cylindrical plug 11. The center of the plug 11 on the flat plate 9 should coincide with the center of the die cavity. The flat plate 9 has four threaded holes 8 corresponding to the die 2.

[0023] The above embodiments are only the preferred specific implementation of the present application, not the limitation of the technical solutions of the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify or replace the present application. Any modification, partial replacement, improvement, etc. made within the spirit and principles of the present application should be included in the scope of the claims of the present application.

Claims

1. A method and apparatus for testing the frictional force between a rectangular mold cavity and a preform under compression, characterized by: The device is connected with the universal testing machine through the base connector, the mold and the compression member, the mold is connected with the universal testing machine through the base, and the centering problem is solved, the compression member is installed above the testing machine, the compression member is controlled by the lifting of the testing machine, and finally the required compression friction force is measured; The length, width and thickness of the compression member are all smaller than those of the mold cavity by about 1mm, so as to eliminate the friction between the compression member and the mold cavity; The base is divided into a flat plate and a cylindrical pin, the center of the pin on the flat plate should coincide with the center of the mold cavity, and the flat plate has four threaded holes corresponding to the mold.

2. A method and apparatus for testing the friction of a rectangular mold cavity against a preform under compression as defined in claim 1, wherein: The compression member is connected with the testing machine through the upper end cylinder, and the lower end of the compression member is a T-shaped member, the upper part of the T-shaped member is the main component for bearing pressure, and the lower compression plate is the main test end.

3. A method and apparatus for testing the friction of a rectangular mold cavity against a preform under compression as defined in claim 1, wherein: The mold is connected with the base through the threaded hole, and the threaded hole of the mold is located on the upper and lower mold plates.

4. A method and apparatus for testing the friction of a rectangular mold cavity against a preform under compression as defined in claim 1, wherein: During the test, the compression member is first lowered into the empty mold cavity, if the friction force at this time is zero, the mold and the testing machine are centered, and then the edge of the fabric in the mold cavity is flush with the edge of the mold cavity.

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