Multi-axial fatigue testing machine

Abstract

A multi-axial fatigue testing machine is disclosed. A drive unit is adopted to provide circulation power, and circulation force is transferred through a force transmission arm, a sliding device and a force transmission spring to a test piece such that the test piece is in a multi-axial fatigue stress state. By selecting the drive unit to connect bolt holes at different positions, multi-axial stress amplitude load applied on the test piece is adjusted; by replacing force transmission springs with different stiffness coefficients, stress amplitude load applied on the test piece is adjusted; and by changing moving displacement of a fixed device in a slide, different magnitudes of one-way initial stress or multi-way initial stress are applied. Therefore, the multi-axial fatigue testing machine can carry out a multi-axial fatigue test of a component by selecting reasonable magnitudes of stress amplitude and initial stress according to different force environments.

Description

technical field [0001] The invention relates to a structural multi-axis testing machine, which belongs to the field of structural testing. Background technique [0002] Metal fatigue damage is a very common phenomenon, and it is one of the most important failure modes in the fields of aerospace, ocean and land transportation, housing construction, nuclear energy and chemical industry. According to statistics over the past 100 years, more than 80% of metal parts are damaged due to fatigue. In engineering practice, most machinery and engineering structures are subjected to multi-axial cyclic loads. Even under the action of uniaxial external loads, due to the complex geometry of engineering structures, their local parts are still in a multi-axial stress state, and correspondingly, their failure Type also belongs to multiaxial fatigue failure. [0003] From the beginning of the development of fatigue theory, people only carried out in-depth and comprehensive research on uniaxi...

AI Technical Summary

Problems solved by technology

The energy method believes that the multiaxial fatigue damage is closely related to the cyclic plastic deformation and plastic strain energy of the material, and the accuracy is high, but its derivation process is complicated and it is not easy to apply in practice

The critical plane method is a new method proposed on the basis of physical observations. It is now considered to be the most effective method for solving multiaxial fatigue problems. However, due to the limitations of current multiaxial fatigue test conditions, many multiaxial damage parameters are still Further research and experimental verification are required

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