Deformation measurement of testing machine based on laser interference method

Tensile, compressive and universal testing machine (Hereinafter referred to as testing machine) is an important instrument for analyzing the pressure of materials. In order to reasonably assess the influence of the deformation of the beam and fixture on the strength analysis of the tested material, the deformation of the beam and fixture of the tested machine, which under the stress state, should be studied. Firstly, the laser interference method is proposed to measure the mechanical deformation characteristics of the beam and fixture. Secondly, we should analyze the structure and theory of measurement technology, give the test method and then calculate the relationship between the deformation of crossbeam and fixture and the stress. Finally, the experimental data are summarized, and the numerical correction method of material shape variables is obtained when testing materials are measured. The experimental results show that the shape variables between the beam and fixture of the testing machine reaches to 0.57mm when the force value reaches to 5 kN. By using this measurement method, the shape variables of the beam and fixture of the testing machine can be measured accurately, and the material deformation can be corrected relevantly during test and analysis of the material strength, which can improve the measurement accuracy of the material deformation for the testing machine.