A sample preparation method for tensile performance test of unidirectional carbon fiber cloth

Abstract

Embodiments of the present invention disclose a unidirectional carbon fiber cloth tension property testing sample preparation method. According to the present invention, a tension device is used to apply tension force along a weft direction so as to make the silk beam maintain a parallel and straightening state during a carbon fiber cloth sheet forming process, increase the accuracy and the reliability of the tensile strength of the tension property testing sample strip, and make the qualification rate of the tension property testing sample strip achieve 100%; a scale ruler is placed on a glass flat plate, such that the distribution of the unidirectional carbon fiber cloth sheet and the unidirectional carbon fiber cloth sample strip resin is uniform, the deposition can not be generated, the stress centralization phenomenon during the tension property testing process can be eliminated, and the probability of the advanced damage on the sample is reduced; and both ends of the unidirectional carbon fiber cloth sample strip are subjected to one-time curing forming to form the resin type reinforcement sheet so as to replace the external-adhesion aluminum sheet or fiber reinforced resin and other traditional reinforcement sheet, eliminate the technical problems of deviated tension, irregular stress-deformation curve and the like caused by the external-adhesion and the improper roughening treatment on the traditional reinforcement sheet, and improve the accuracy and the reliability of the testing result.

Description

technical field [0001] The invention belongs to the field of preparation methods of material test samples, and in particular relates to a sample preparation method for tensile performance test of unidirectional carbon fiber cloth. Background technique [0002] In recent years, carbon fiber has been widely used in various fields of the national economy due to its excellent properties such as high strength, high modulus, and low density. It has the advantages of light weight, high strength, corrosion resistance, convenient construction, and small impact on the environment. It has been widely used in reinforcement and repair projects of concrete structures. In the above projects, the mechanical properties of unidirectional carbon fiber cloth are the key factors affecting the properties and use of carbon fiber cloth and carbon fiber reinforced composite materials. Therefore, the test to correctly reflect the mechanical properties of unidirectional carbon fiber cloth has become ...

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Problems solved by technology

[0004] 1. During the process of impregnating unidirectional carbon fiber cloth with resin, the rolling of the glass rod will cause the carbon fiber tows to bend, shift, and wrinkle, making the tows non-parallel, which may lead to tension during the tensile test. The carbon fiber strands of the elongation test sample are broken at the same time, so that the tensile strength obtained in the test is low; in addition, the non-parallel or non-straightening of the carbon fiber strands will also increase the scrap rate of the unidirectional carbon fiber cloth sample;

[0005] 2. The unidirectional carbon fiber cloth sheet prepared by this sample preparation method is easy to cause resin deposition, which makes the glue content of the unidirectional carbon fiber cloth sample cut into unevenness, and aggravates the tensile property test sample during the stretching process. Stress concentration will lead to premature failure of the spline;

[0006] 3. In this sample preparation process, it is necessary to bond traditional duralumin materials or fiber reinforced resins as reinforcement sheets. Before pasting the traditional reinforcement sheets, it is necessary to cut, roughen and make chamfers on the traditional reinforcement sheets, which is time-consuming and labor-intensive. , which makes the test cost high and the test cycle long; in addition, the rough grinding of the reinforcement sheet will cause the reinforcement sheet to fall off, causing deviations in the test results;

[0007] 4. When bonding the traditional reinforcement sheet, the amount of glue applied to the reinforcement sheet is not easy to control, which leads to thicker or uneven thickness of the reinforcement sheets at both ends of the test sample, which makes the force direction of the tensile test sample during the tensile test A certain angle is formed with the direction of the spline, which generates a bending moment, which causes the torsion to occur during the loading process of the test spline, resulting in biased stretching during the tensile performance test, and problems such as irregular stress-deformation curves, resulting in tensile strength The values ​​of elongation and elongation are low, which cannot reflect the real performance of the material;

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