Biaxial tension test calibration debugging method based on crossed test piece

Abstract

The invention discloses a biaxial tension test calibration debugging method based on a crossed test piece. The biaxial tension test calibration debugging method comprises the following steps: pastinga strain rosette to a specific position of the crossed test piece, and carrying out calculation by virtue of the strain rosette to obtain a shearing strain at the pasted position; regulating an actuator or other connecting members so that the value change rule and the value of the shearing strain are basically consistent within an elastic range, and in such a case, considering that the test piecehas a relatively small additional load; and carrying out loading after clearing data according to a general mechanical test on the basis to finish calibration. The debugging method is simple in adopted equipment, easy to implement, capable of achieving a relatively good calibration effect and suitable for calibration debugging before dynamic tests such as a quasi-static test or a fatigue test.

Description

technical field [0001] The invention belongs to the technical field of physical performance testing of engineering materials, and in particular relates to a calibration debugging method for bidirectional tensile tests based on a cross-shaped test piece. Background technique [0002] The mechanical properties of materials under complex stress states will show complexity. Compared with uniaxial tests, biaxial tests can be used to obtain more realistic mechanical parameters or responses of materials. Generally speaking, there are many loading forms of biaxial test, among which the most intuitive one is biaxial tensile test based on cross-shaped specimen. [0003] At present, there is no standard test piece and no standard test procedure for this kind of bidirectional tensile test. Compared with uniaxial test, the difficulty of biaxial loading lies in the coordinated control of forces in two directions, which also puts forward higher requirements for calibration and debugging b...

AI Technical Summary

Problems solved by technology

Whether it is calibration and debugging or coordinated loading, the fundamental purpose is to ensure the accuracy of the test. At present, the accuracy of the testing machine and the clamping of the test piece are mainly used to ensure the accuracy. This method does not fully consider the difficulties of biaxial loading, nor It is impossible to perform quantitative calibration and debugging, and it is easy to cause additional in-plane bending moment or torque on the test piece

For the loading of the cross-shaped test piece, in addition to the tensile stress generated by the bidirectional tensile force, shear stress will be generated in the local area. Under ideal conditions, the shear stress level in the central area of ​​the cross-shaped test piece should be much smaller than the normal stress. If Conducting the test directly without calibration and debugging will cause problems such as inaccurate experimental data, wrong or inconspicuous results, etc.

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