Method for testing biaxial yield and hardening behaviors of sheet metal

Abstract

The invention relates to the technical field of deformation testing of sheet metal, in particular to a method for testing biaxial yield and hardening behaviors of the sheet metal. Novel cross-shaped specimen geometry is designed in the method, and biaxial initial yield stress and follow-up yield stress of the sheet metal are obtained directly by measuring biaxial load; the designed specimen is characterized by comprising grooves with slotted openings and thinned central deformation area, and yield moment of the sheet metal and strain corresponding to follow-up hardening are determined by measuring strain of a fixed central point of the thinned area in real time. According to the method, biaxial initial yield stress and follow-up yield stress (hardening) of the sheet metal are obtained directly by measuring the biaxial load under the condition of the fixed strain tracing point. By means of the strain of the fixed central trace point in a biaxial loading process of the novel cross-shapedspecimen, the biaxial initial yield stress and follow-up yield stress value can be obtained directly according to the measured biaxial load, and the testing method is simple and high in controllability.

Description

technical field [0001] The invention relates to the field of deformation testing of metal plates, in particular to a new method for testing the biaxial yield and hardening behavior of metal plates, which uses cross-shaped samples to obtain the yield and hardening behaviors of metal plates under different strain paths. Background technique [0002] The yield and hardening of metal materials are important deformation behaviors in the process of metal plastic deformation, which not only reflects the realization characteristics of metal materials (anisotropic yield and hardening, etc.), but also affects the dimensional accuracy of metal parts (part thickness change and springback, etc.) ). The macroscopic constitutive equation aims to accurately describe the yield and hardening behavior of metal materials, and then give accurate prediction of mechanical response and dimensional accuracy during plastic processing. [0003] At present, in order to describe the deformation behavio...

AI Technical Summary

Problems solved by technology

This method is currently widely used, but there are the following problems: (1) The determination of the strain tracking position is relatively complicated, requiring a lot of numerical simulation work, and the material constitutive input of the simulation is virtual, resulting in a large deviation between the calculation results and the actual; (2) Since the determined strain tracking position is not in the center of the sample, it is difficult to locate accurately during the actual strain test; (3) It can only be used to test the initial yield stress of the metal plate, and cannot obtain the subsequent yield stress

The above problems lead to the implementation of the current test method is complicated and the measurement error is large. At the same time, the subsequent yield stress of different tests

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