Study On Damage Numerical Modeling And Optical-Mechanical Hybrid Optimization Calibration Of High-Strength Steel

With the advent of the 5G era,the automobile industry has gradually entered a new era.With the development of unmanned vehicles and new energy technologies,the automobile industry has moved towards a new transformation,and there are more stringent requirements for automobile lightweight.The uneven deformation mechanism between multiphase structures during plastic deformation of high-strength steel makes the failure mode of high-strength steel change from damage fracture after instability to damage-oriented failure mode.In addition,high-strength steel has high strength,relatively small fracture strain and small process window,so the process limit of materials must be tapped,so accurate modeling of damage evolution is the key to high-precision prediction of plasticity and fracture behavior of high-strength steel.It is of great significance to ensure the forming quality of high-strength steel,improve the formability of high-strength steel and study the damage mechanism of high-strength steel in the forming process.Based on the above research background,this paper adopts the method of optical and mechanical mixed measurement to study the reverse calibration of damage hardening parameters of high strength steel,which mainly includes:(1)Based on the basic principle of digital image correlation method,the quality of speckle image is evaluated by qualitative and quantitative methods to improve the calculation accuracy of digital image correlation method.(2)A universal testing machine system with DIC image acquisition system is built based on LABVIEW program,and the synchronous acquisition of image data and load displacement test data is realized.The DIC image data is processed twice by MATLAB program,and the damage instability point and crack shape of the material during loading are calculated and calibrated,and the crack kinematics theory is constructed,and the curve similarity evaluation method system is established,which provides various schemes for material parameter optimization.(3)Based on Voce+Voce hardening model and Lemaitre damage model,the damage model of high-strength steel in tensile process is established,and the damage mechanism in tensile process is analyzed.Based on ABAQUS software,the tensile process of high strength steel under different stress states is simulated.Based on different damage parameters and optimization methods,an optimization sub-model is established.Based on experimental data and simulation data,an optimization convergence criterion and an optimization strategy are designed,and the material parameters in the damage process are comprehensively optimized and calibrated.