Material parameter acquisition method based on DIC technology

Abstract

The invention discloses a material parameter acquisition method based on a DIC technology. A unilateral notch tensile experiment is carried out, speckles are sprayed on the surface of a sample, data acquisition is carried out by adopting DIC digital image measurement equipment in the experiment process, a load displacement curve of a material is obtained from a testing machine, the three-dimensional size information is obtained from the DIC, and a finite element model is established; the load displacement curve of the testing machine and a target load displacement response curve are corrected;and the load displacement information is obtained and evaluated. By combining a digital image related method and a finite element method, the material parameters of the sample can be reasonably and accurately obtained. The method is wide in applicability and can be used for metal materials and most non-metal materials. The experiment times can be greatly reduced, and the time is shortened, so that the material cost is reduced.

Description

technical field [0001] The present invention relates to a method for measuring metal materials, and more specifically, to a method for acquiring material parameters based on DIC technology. Background technique [0002] The traditional method of measuring metal material parameters is to obtain the load-displacement curve in the gauge length section through the uniaxial tensile test of the material sample, and then convert it into the performance curve of the material. This traditional method requires an additional batch of standard tensile samples to be processed when making fatigue samples, and has higher requirements on the manufacturing and processing technology of tensile samples. Not only that, when the traditional method calculates the material parameters, it is assumed that the deformation of the sample is uniform in the gauge length section during the stretching process, but in fact, no matter whether the rod-shaped tensile sample or the plate-shaped tensile During ...

AI Technical Summary

Problems solved by technology

Not only that, when the traditional method calculates the material parameters, it is assumed that the deformation of the sample is uniform in the gauge length section during the stretching process, but in fact, no matter whether the rod-shaped tensile sample or the plate-shaped tensile During the process, there will be more or less small defects, or there is residual stress on the surface of the sample, and the deformation of the gauge length section during the stretching process is not completely consistent.

During the stretching process, the part with microscopic small defects will have a large deformation, while the rest of the defect-free part will have a much smaller deformation. In this case, the calculated material parameters are not accurate enough

[0003] In the traditional tensile test on the testing machine, due to the phenomenon of elastic deformation and gaps of the beam during the operation of the testing machine, there will be some inevitable experimental errors, which will have a certain impact on the experimental results, resulting in the displacement measurement value. large error

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