Method for testing interfacial fracture toughness of second-generation high-temperature superconducting strip

Abstract

The invention provides a method for testing the interfacial fracture toughness of a second-generation high-temperature superconducting strip. The method comprises the steps of: (1), solidifying an enhancement layer, the thickness of which is much greater than the superconducting strip, at two sides of the superconducting strip, so that a composite beam structure is formed and used as a sample to be tested; (2), coating speckles at the narrow side of the sample in the length direction; (3), cutting the initial crack at one end of the superconducting strip of the sample, then, loading the sampleon a stretcher, and aligning a CCD camera to one side of the sample, on which the speckles are coated; (4), respectively developing type I and II interlayer fracture experiments; and (5), obtaining type I and II interlayer fracture toughness of the sample by calculation by using a digital image correlation method, wherein the result is the type I and II interlayer fracture toughness of the superconducting strip. According to the method provided by the invention, the enhancement layer, the thickness of which is much greater than the superconducting strip, is increased at two sides of the superconducting strip; therefore, the fracture toughness of the superconducting strip can be measured by a conventional experimental method; and furthermore, the experimental method is simple and high in accuracy.

Description

technical field [0001] The invention belongs to the technical field of superconducting strip experiments, and relates to a second-generation high-temperature superconducting strip interface fracture toughness test method. Background technique [0002] The second-generation high-temperature superconducting tape is a typical laminated composite material, and the interface peeling between layers often occurs, which seriously affects the use of the tape. Since the thickness of the second-generation high-temperature superconducting strip is very thin (thickness is about 0.1 mm), and it has an asymmetric structure along the thickness direction of the material, such structural features make it difficult to capture the deformation characteristics of superconducting materials, especially the crack tip during deformation. . In addition, because the superconducting tape is very thin, it is difficult to test it with the traditional method of testing the interface fracture toughness of ...

AI Technical Summary

Problems solved by technology

[0002] The second-generation high-temperature superconducting tape is a typical laminated composite material, and interlayer delamination often occurs, which seriously affects the use of the tape.

In addition, due to the thinness of the superconducting tape, it is difficult to test it with the traditional method of testing the interface fracture toughness of composite materials

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