Adaptive enrichment meshfree simulation and experiment on buckling and post-buckling analysis in sheet metal forming

Sheet buckling, a form of instability, is one of the major considerations in the design of part shape, die geometry and processing parameters of sheet metal forming. In this study, an adaptive enrichment meshfree method is developed to capture wrinkling and post-buckling behavior in sheet metal forming. A three-dimensional meshfree continuum approach is applied to the large deformation of plate/shell structures. A stress-based wrinkling predictor is used to predict the onset of buckling within effective compressive regions. Enrichment particles with a proper enrichment function are inserted/deleted in those regions to capture the buckling mode and therefore post-buckling behavior. For verification of the simulation results, a high-resolution wedge strip test is designed to study the onset and post-buckling behavior of a sheet under different boundary conditions.