Cross-shaped test piece biaxial tensile test based yield criterion evaluation method

Abstract

The invention provides a cross-shaped test piece biaxial tensile test based yield criterion evaluation method. According to the relation of the real stress in a rolling direction and plastic strain, the relation of biaxial directional stress and equivalent stress can be deduced by adopting a yield criterion, the relation of plastic strain in a biaxial direction and equivalent plastic strain can bededuced, the relation of biaxial directional strain and the equivalent plastic strain can be obtained, and therefore, the relation of stress and strain in the biaxial direction can be obtained; dataof the equivalent stress and the equivalent plastic strain can be measured by a test, so that data of elastic and plastic stages in the biaxial direction can be obtained; the expressions of two curvescan be obtained through curve fitting, contrast can be performed on the biaxial directional data measured by the test and the expressions, and the prediction precision of the deformational behavior of a material corresponding to the yield criterion can be evaluated. The contrast of the difference between the relation of stress and strain in the biaxial direction obtained by the test and the yieldcriterion in the whole plastic stage can be realized; and the limitation that traditional methods can only compare the difference between a test yield point and the yield criterion under a certain equivalent plastic strain can be overcome.

Description

technical field [0001] The invention relates to a biaxial tensile strength analysis method, in particular to a yield criterion evaluation method. Background technique [0002] In many engineering fields such as aviation, aerospace, machinery, etc., components often bear loads in multiple directions during work. Under complex stress conditions, the mechanical behavior of metal materials presents very complex characteristics. Only relying on uniaxial tensile tests is The yield characteristics of components and materials cannot be accurately analyzed. Therefore, in order to study the deformation behavior and constitutive relationship of metal materials more accurately, it is necessary to study the mechanical behavior of materials under different loading paths. [0003] At this stage, biaxial tensile tests are mostly used to realize different loading paths. Most of the specimens in biaxial tensile tests are cross-shaped specimens, which can effectively improve the uniformity of...

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Problems solved by technology

However, this method can only predict the yield criterion under a certain plastic strain each time, the continuity is poor, and the prediction accuracy of the yield criterion in the entire plastic stage cannot be well analyzed.

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