High-pressure hydrogen environment material testing machine fatigue test fixture

Abstract

The invention relates to material mechanics performance testing equipment and aims to provide a high-pressure hydrogen environment fatigue test clamp for a material testing machine. The clamp comprises an upper clamp and a lower clamp, wherein each of the upper clamp and the lower clamp comprises a support, a connection plate, a connection rod, a locking piece and a base plate; a spherical hinge turning pair is formed by the connection rod and the support form, and another spherical hinge turning pair is formed by the support and the connection plate; a groove with a step is formed at one end of the chassis and is used for matching with a positioning lug boss of the connection plate; the upper clamp and the lower clamp are symmetrical up and down in the assembly direction of each component. The clamp is applicable to a test piece to bear the fatigue tests of pulse stretching, asymmetrical stretching, pulse compression, asymmetrical compression, symmetrical tension and compression and asymmetrical tension and compression in the high-pressure hydrogen environment; a threaded structure of the clamp only needs to bear a stretching load design effect in a full test process, so as to avoid a loosing phenomenon of the thread structure under a circular tension and compression load. Not only can the test piece be automatically aligned, but also the test piece can be fastened and clamped, so that the accuracy of the test data is improved.

Description

technical field [0001] The invention belongs to testing equipment for mechanical properties of materials, in particular to a fatigue test fixture of a high-pressure hydrogen environment material testing machine. Background technique [0002] The test equipment for the mechanical properties of materials in a high-pressure hydrogen environment mainly adopts the form of docking the high-pressure hydrogen environment box on the main machine of the existing testing machine. In order to reduce the amount of hydrogen used, the design space of the high-pressure hydrogen environment box is less, and it is difficult to use hydraulic clamps to hold the sample. If the ordinary fixture with threaded connection is directly used, it is easy to cause misalignment, and the additional bending moment on the sample is large, which seriously affects the authenticity of the test results. [0003] At present, the improved fixtures proposed in the literature to improve the neutrality of the sample...

AI Technical Summary

Problems solved by technology

If the ordinary fixture with threaded connection is directly used, misalignment is likely to occur, and the additional bending moment on the sample is large, which seriously affects the authenticity of the test results.

[0003] At present, the improved fixtures proposed in the literature to improve the neutrality of the sample are mainly for tensile tests, and are relatively small for fatigue tests. Some even have large and complex structures and high installation requirements, which are not suitable for hydrogen environments with small spaces. In-box application

Although the ZL94236615.8 high-frequency fatigue testing machine axial fatigue test fixture, it is proposed that the fixture with a spherical surface and a threaded core in the center hole, a spherical hinge support and a sample to form a rotary pair structure can be used in a hydrogen environment box. Automatic centering of fatigue test specimens, but in this structure, due to the threaded connection between the specimen and the spherical core, and the threaded structure is prone to loosening under repeated tension and compression loads, causing the specimen to not be clamped tightly. Finally lead to poor alignment performance

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