Method for obtaining high-precision hardening model parameters of material in complex stress state

Abstract

The invention discloses a method for obtaining high-precision hardening model parameters of a material in a complex stress state. The method comprises the following steps: S1, obtaining a force-displacement curve of the material in a uniaxial tensile stress state; S2, calculating an engineering stress-engineering strain curve; S3, calculating a true stress and true strain curve; S4, calculating an effective stress-strain curve; S5, performing fitting epitaxy on the effective stress-strain curve to obtain an epitaxial stress-strain curve; S6, adjusting the line shape of the fitting curve; S7, establishing numerical models for the material samples in different stress states, and comparing force-displacement curves in test and simulation results; and S8, returning to the step S6, and optimizing the weighting coefficient until the benchmarking result in the step S7 meets the requirement. According to the method, material samples in different stress states are subjected to simultaneous benchmarking and optimization iteration to obtain high-precision hardening model parameters, the problem that material performance characterization in different stress states cannot be considered at the same time in the existing hardening model parameter establishing process is solved, and the defects existing in an existing method are overcome.

Description

technical field [0001] The invention relates to the technical field of material mechanics testing, in particular to a method for obtaining high-precision hardening model parameters of materials under complex stress states. Background technique [0002] At present, the true stress and true strain curves of materials are often obtained through uniaxial tensile tests, and the true stress and true strain curves obtained by experimental tests are only valid before the necking point. However, since the plastic strain corresponding to the necking point is often small, taking hot-formed steel as an example, it is only 0.05, so this curve alone cannot be used to characterize the deformation behavior of materials under large deformation. For this reason, researchers often use the method of hardening model fitting extension combined with simulation benchmarking to obtain the true stress and true strain curve of the material after the compression point. However, this method has the fol...

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Problems solved by technology

[0006] The purpose of the present invention is to propose a method for obtaining high-precision hardening model parameters of materials under complex stress conditions in view of the problems existing in the establishment of the current material hardening model parameters, mainly to solve the problem that different factors cannot be considered simultaneously during the establishment of hardening model parameters. The problem of material performance characterization under stress state, find higher precision material hardening model parameters under different stress states, and overcome the shortcomings of existing methods

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