Identification for elastoplastic constitutive parameters of 316L stainless steel lattice structures using finite element model updating and integrated digital image correlation

Lattice structures are widely considered for industrial applications owing to their excellent energy absorption and mechanical properties. In this work, octet-truss lattice structures are manufactured from 316L stainless steel powder by selective laser melting (SLM). The geometrical information of lattice structures is captured by SEM and X-ray tomography. It reveals that realistic dimensions of struts differ slightly from CAD-designed ones. The mechanical behaviors are investigated both experimentally and numerically. Quasi-static uni-axial compression experiments with 2D digital image correlation (DIC) technology are conducted to measure displacement/strain fields. Finite element analysis based on an elastic and anisotropic plastic constitutive model is used to simulate mechanical behaviors. To improve the predictive accuracy, a finite element model updating approach is implemented to identify constitutive parameters. The results show that numerical simulation with optimized parameters match well with experiments in aspect of force-displacement curve at elastic–plastic stage and displacement fields.