Enhanced Hole Expansion Predictions for Laser-Polished DP1000 Steel Using Multiscale Simulation

A multiscale FE simulation has been conducted for DP1000 sheet material with a thickness of 1.5 mm, which exhibits enhanced edge roughness due to laser-polishing. A smoother geometry and a new martensitic structure at the edge were observed during the laser-polishing process for the hole expansion sample. The effects of this new edge geometry are considered in the macroscopic simulation. The material characterization of the martensitic microstructure is performed based on the findings from heat treatment experiments. The coupled modified Bai-Wierzbicki (MBW) damage model is employed to predict damage behavior in the macroscopic simulation of the hole expansion test. In the microscopic simulation, the same material characterization resulting from heat treatment was applied, while local roughness was represented using actual measured roughness data. The macroscopic simulation’s damage criterion has been optimized by utilizing surface parameters. Bridging the roughness information from the microscopic simulation to the macroscopic simulation demonstrates that simulation results better agree with experimental outcomes.