Preparation method of tensile property test sample strip of composite material laminated plate

Abstract

The invention relates to a preparation method of a tensile property test sample strip of a composite material laminated plate. The preparation method comprises the following steps: a laying step: laying a plurality of layers of continuous fiber reinforced thermoplastic resin prepreg tapes to form a laminated prepreg tape; a reinforcing step: selecting a preset range on the laminated prepreg tape to lay reinforcing sheets; and a hot-pressing step: carrying out hot-pressing compounding on the laminated prepreg tape paved with the reinforcing sheets to form the composite material laminated plate. According to the preparation method of the sample strip for testing the tensile property of the composite material laminated plate, the binding force of the prepared side sample strip reinforcing sheet is strong, and a clamp is effectively prevented from slipping at the clamping end during testing.

Description

Technical Field

[0001] The present application relates to the technical field of composite materials, and in particular to a method for preparing a composite material laminate tensile property test specimen. Background Art

[0002] At present, during the testing process of ultra-thin continuous fiber reinforced thermoplastic composite laminates, serious slippage is prone to occur at the clamping end. According to the national standard GBT 1447-2005 "Test Method for Tensile Properties of Fiber Reinforced Plastics", reinforcement sheets can be connected at both ends of the specimen for reinforcement to overcome slippage.

[0003] However, for some laminates whose matrix resins are made of non-polar materials (such as polypropylene), the surface of the material itself is polar, and it is difficult to firmly connect the reinforcing sheet with ordinary adhesives. During testing, the reinforcing sheet may detach and the clamping end may slip.

[0004] Therefore, a method for preparing a composite laminate tensile property test specimen is needed to at least partially solve the above problems. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] In order to at least partially solve the above problems, the present application provides a method for preparing a composite material laminate tensile property test specimen, the preparation method comprising:

[0007] Laying step: laying multiple layers of continuous fiber reinforced thermoplastic resin prepreg tapes to form a stacked prepreg tape;

[0008] Reinforcement step: laying a reinforcement sheet in a preset range on the stacked prepreg tape;

[0009] Hot pressing step: hot pressing the stacked prepreg tapes with the reinforcement sheet laid thereon to form a composite body of the composite material laminate and the reinforcement sheet.

[0010] According to the method for preparing composite material laminate tensile performance test strips of the present application, the manufactured side strip reinforcement plates have strong bonding force, which effectively prevents the fixture from slipping at the clamping end during testing.

[0011] Optionally, the strengthening step further includes:

[0012] Laying a reinforcing sheet above the stacked prepreg tapes at a preset distance;

[0013] A lower reinforcing sheet is laid below the stacked prepreg tapes at a preset distance, and the upper reinforcing sheet is vertically aligned with the lower reinforcing sheet.

[0014] Optionally, the reinforcing step further includes: laying a compensation sheet between two adjacent upper reinforcing sheets and two adjacent lower reinforcing sheets.

[0015] Optionally, the preparation method further comprises:

[0016] Cutting step: cutting the composite body according to the preset range and removing the compensation sheet to obtain the test material.

[0017] Optionally, the preparation method further comprises:

[0018] Carving step: Carving the test material according to the testing standard to obtain the tensile performance test specimen.

[0019] Optionally, the test material has a first side and a second side arranged in opposite directions along the stretching direction, and the outer edges of the two reinforcing sheets spaced apart by the preset distance form the first side and the second side;

[0020] The test specimen includes clamping parts located at two ends along the stretching direction and a part to be tested located between the two clamping parts, and the reinforcing sheet is located at the clamping parts.

[0021] Optionally, the engraving step further comprises:

[0022] An engraved standard line is marked on the test material, wherein the engraved standard line is perpendicular to the stretching direction, and the distance between the engraved standard line and the inner edge of the reinforcing sheet is the length dimension of the clamping portion.

[0023] Optionally, the thickness of the compensation sheet is the same as the thickness of the reinforcement sheet.

[0024] Optionally, the reinforcing sheet is a composite material sheet or a resin sheet, and the matrix resin of the reinforcing sheet is compatible with the matrix resin of the continuous fiber reinforced thermoplastic resin prepreg tape.

[0025] Optionally, the compensation sheet is a composite material sheet or a resin sheet, and the matrix resin of the compensation sheet is incompatible with the matrix resin of the continuous fiber reinforced thermoplastic resin prepreg tape. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following drawings of the present application are used as a part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, which are used to explain the principle of the present application.

[0027] In the attached figure:

[0028] Figure 1 A simplified flow chart of a method for preparing a composite material laminate tensile property test specimen according to an embodiment of the present application;

[0029] Figure 2 A more detailed flow chart of a method for preparing a composite laminate tensile property test specimen according to one embodiment of the present application;

[0030] Figure 3 is a schematic top view of a test material according to an embodiment of the present application;

[0031] Figure 4 A schematic top view of a composite laminate tensile properties test specimen according to an embodiment of the present application; and

[0032] Figure 5 It is a side view schematic diagram of a composite laminate tensile property test specimen according to one embodiment of the present application;

[0033] Fig. 6A A photograph of the failure morphology of a tensile test of a test specimen without a reinforcement sheet in the prior art; and

[0034] Figure 6B The figure is a photograph of the failure morphology of a test specimen in a tensile test according to an embodiment of the present application.

[0035] Description of reference numerals:

[0036] 100: tensile properties test specimen

[0037] 110: Clamping part

[0038] 120: Part to be tested

[0039] 10: Composite laminates

[0040] 20: Enhancement film

[0041] 21: Upper reinforcement plate

[0042] 22: Lower reinforcement sheet

[0043] 30: Compensation film

[0044] 40: Test materials

[0045] 41: First side

[0046] 42: Second side

[0047] D: stretching direction

[0048] Ln: Engraving standard line DETAILED DESCRIPTION

[0049] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of the features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0051] Ordinal numbers such as "first" and "second" cited in this application are merely identifiers and do not have any other meaning, such as a specific order, etc. Moreover, for example, the term "first component" itself does not imply the existence of a "second component", and the term "second component" itself does not imply the existence of a "first component". It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer" and similar expressions used in this document are for illustrative purposes only and are not limiting.

[0052] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings.

[0053] refer to Figure 1 The present application provides a method for preparing a composite material laminate 10 tensile property test specimen 100, which includes a laying step, a strengthening step and a hot pressing step.

[0054] The laying step includes laying multiple layers of continuous fiber reinforced thermoplastic resin prepreg tapes to form a stacked prepreg tape. The reinforcing step includes laying a reinforcing sheet 20 in a preset range on the stacked prepreg tape. The hot pressing step includes hot pressing the stacked prepreg tapes with the reinforcing sheet 20 to form a composite body of the composite laminate 10 and the reinforcing sheet 20.

[0055] According to the method for preparing the tensile performance test strip 100 of the composite laminate 10 of the present application, the manufactured side strip reinforcement sheet 20 has a strong bonding force, which effectively prevents the fixture from slipping at the clamping end during the test.

[0056] refer to Figure 1 and Figure 2The preparation method further includes a cutting step and a carving step. The cutting step includes cutting the composite body according to a preset range to obtain a test material 40. The carving step includes carving the test material 40 according to the test standard to obtain a tensile performance test specimen 100.

[0057] refer to Figure 4 and Figure 5 The test specimen includes a clamping portion 110 located at both ends along the stretching direction D and a test portion 120 located between the two clamping portions 110. The reinforcing sheet 20 is located at the clamping portion 110, wherein the length dimension of the clamping portion 110 is L1, and the length dimension of the test portion 120 is L2. Figure 3 The test material 40 has a first side 41 and a second side 42 that are oppositely arranged along the stretching direction D, and the outer edges of the two reinforcing sheets 20 spaced apart by a preset distance form the first side 41 and the second side 42. In other words, the inner edges of the two reinforcing sheets 20 spaced apart by a preset distance serve as the test portion 120 of the spline, which has a length dimension L2 of the test portion 120.

[0058] refer to Figure 2 and Figure 3 The engraving step specifically includes marking an engraving standard line Ln on the test material 40 , the engraving standard line Ln is perpendicular to the stretching direction D, and the distance between the engraving standard line Ln and the inner edge of the reinforcing sheet 20 is the length dimension L1 of the clamping portion 110 .

[0059] Since the test specimen is tightened by both sides of the fixture during the test, it is preferred to set reinforcing sheets 20 on both sides of the test specimen. As a preferred embodiment, the reinforcing step also includes laying an upper reinforcing sheet 21 above the stacked prepreg tape at a preset distance and laying a lower reinforcing sheet 22 below the stacked prepreg tape at a preset distance, and the upper reinforcing sheet 21 is vertically aligned with the lower reinforcing sheet 22. The preset distance is the length dimension L2 of the above-mentioned part 120 to be tested.

[0060] The reinforcing sheet 20 is a composite sheet or a resin sheet. The matrix resin of the reinforcing sheet 20 is compatible with the matrix resin of the continuous fiber reinforced thermoplastic resin prepreg tape, and the purpose is to enable the reinforcing sheet 20 to be integrated or tightly bonded with the laminate through hot pressing. Preferably, the matrix resin of the reinforcing sheet 20 is the same as the matrix resin of the continuous fiber reinforced thermoplastic resin prepreg tape. Therefore, the reinforcing sheet 20 is laid before hot pressing and hot pressed together with the prepreg tape, so that the reinforcing sheet 20 and the laminate can be integrated, which greatly improves the bonding strength.

[0061] However, since the reinforcing sheet 20 has a certain thickness, the reinforcing sheet 20 first contacts the die during hot pressing, which will cause the prepreg to be insufficiently pressed. For this reason, it is preferred to compensate for the thickness of the reinforcing sheet 20. As an implementation form, the reinforcing step also includes laying a compensation sheet 30 between two adjacent upper reinforcing sheets 21 and two adjacent lower reinforcing sheets 22. The thickness of the compensation sheet 30 is the same as that of the reinforcing sheet 20. The compensation sheet 30 is a composite sheet or a resin sheet. The matrix resin of the compensation sheet 30 is incompatible with the matrix resin of the continuous fiber reinforced thermoplastic resin prepreg tape. The purpose is to prevent the compensation sheet 30 from forming adhesion with the laminate, so that the compensation sheet 30 can be removed when the composite is cut. In other words, the matrix resin of the compensation sheet 30 is preferably different from the matrix resin of the continuous fiber reinforced thermoplastic resin prepreg tape.

[0062] As an example, refer to Fig. 6A The test specimen without reinforcement sheet has direct contact with the clamp at the end, and stress concentration will occur under the action of clamping force, resulting in local damage. In the tensile test, the specimen will slip while stretching, and then split, and the fracture will occur at the clamping end.

[0063] According to the test specimens of the present application with added reinforcement sheets, refer to Figure 6B , which is equivalent to increasing the material thickness at the end, avoiding local damage caused by stress concentration, reducing the vibration and deformation of the spline when subjected to force, ensuring stability during the stretching process, and then presenting the explosive-style fracture characteristics recorded in the national standard GBT 1447-2005 "Test method for tensile properties of fiber-reinforced plastics". This tensile failure pattern can better demonstrate the mechanical properties of the material itself than the above-mentioned failure pattern without reinforcement.

[0064] The processes and steps described in all the above preferred embodiments are only examples. Unless adverse effects occur, various processing operations can be performed in a sequence different from the sequence of the above processes. The sequence of steps in the above processes can also be increased, merged or deleted according to actual needs.

[0065] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present application. The features described herein in one embodiment may be applied to another embodiment individually or in combination with other features, unless the feature is not applicable or otherwise specified in the other embodiment.

[0066] This application has been described through the above embodiments. However, it should be understood that the above embodiments are only for illustrative and explanatory purposes. This application is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of this application, and these variations and modifications all fall within the scope claimed by this application.

Claims

1. A method for preparing a composite material laminate tensile performance test strip, characterized in that: The preparation method comprises: Laying step: laying multiple layers of continuous fiber reinforced thermoplastic resin prepreg tapes to form a stacked prepreg tape; Reinforcement step: laying a reinforcement sheet in a preset range on the stacked prepreg tape; Hot pressing step: hot pressing the stacked prepreg tapes with the reinforcement sheet laid thereon to form a composite body of the composite material laminate and the reinforcement sheet.

2. The method for preparing the composite material laminate tensile property test strip according to claim 1, characterized in that: The strengthening step also includes: Laying a reinforcing sheet above the stacked prepreg tapes at a preset distance; A lower reinforcing sheet is laid below the stacked prepreg tapes at a preset distance, and the upper reinforcing sheet is vertically aligned with the lower reinforcing sheet.

3. The method for preparing the composite material laminate tensile property test strip according to claim 2, characterized in that: The reinforcing step further includes: laying a compensation sheet between two adjacent upper reinforcing sheets and two adjacent lower reinforcing sheets.

4. The method for preparing the composite material laminate tensile property test strip according to claim 3, characterized in that: The preparation method further comprises: Cutting step: cutting the composite body according to the preset range and removing the compensation sheet to obtain the test material.

5. The method for preparing the composite material laminate tensile property test strip according to claim 4, characterized in that: The preparation method further comprises: Carving step: Carving the test material according to the testing standard to obtain the tensile performance test specimen.

6. The method for preparing the composite material laminate tensile property test strip according to claim 5, characterized in that: The test material has a first side and a second side arranged opposite to each other along the stretching direction, and the outer edges of the two reinforcing sheets separated by the preset distance form the first side and the second side; The test specimen includes clamping parts located at two ends along the stretching direction and a part to be tested located between the two clamping parts, and the reinforcing sheet is located at the clamping parts.

7. The method for preparing the composite material laminate tensile property test strip according to claim 6, characterized in that: The engraving step also includes: An engraved standard line is marked on the test material, wherein the engraved standard line is perpendicular to the stretching direction, and the distance between the engraved standard line and the inner edge of the reinforcing sheet is the length dimension of the clamping portion.

8. The method for preparing the composite material laminate tensile property test strip according to claim 3, characterized in that: The thickness of the compensation sheet is the same as the thickness of the reinforcement sheet.

9. The method for preparing a composite material laminate tensile property test strip according to any one of claims 1 to 8, characterized in that: The reinforcing sheet is a composite material sheet or a resin sheet, and the matrix resin of the reinforcing sheet is compatible with the matrix resin of the continuous fiber reinforced thermoplastic resin prepreg tape.

10. The method for preparing a composite material laminate tensile property test strip according to any one of claims 3 to 8, characterized in that: The compensation sheet is a composite material sheet or a resin sheet, and the matrix resin of the compensation sheet is incompatible with the matrix resin of the continuous fiber reinforced thermoplastic resin prepreg tape.

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