Numerical Prediction of Tailored 22MnB5 and 37MnB5 Channels Under Three-Point Bending

This work invesRgated the effect of axial tailoring on hot-stamped channels formed from UsiborÒ 1500 and UsiborÒ 2000 with thicknesses of 1.4mm. The channels were formed in a three-zone die where each zone is able to be independently controlled to create a variety of tailoring condiRons for study. These channels were created for crash tests in a three-point bend loading configuraRon, though quasi-staRc tests were also considered. Numerical models were developed to simulate these condiRons. For the four die quench temperatures considered, 20, 250, 350 and 550°C, Vickers hardness tests and uniaxial tensile tests at four strain rates (0.003, 0.1, 100 and 1500s-1) were conducted to characterize each as-quenched condiRon. Hardness values increased with decreasing quench temperatures and were higher for UsiborÒ 2000 than UsiborÒ 1500. UlRmate tensile strengths behaved similarly, as well as increasing with increased test strain rate. Quasi-staRc three-point bend tests were conducted at a rate of 10mm/min on homogenous channels quenched at 250°C to a maximum displacement of 60mm. The measured force- displacement responses were used to calculate the total energy absorbed by each channel. The average total energy absorbed was 1.273kJ for UsiborÒ 1500 and 1.146kJ for UsiborÒ 2000. Despite experiencing a higher peak force, the UsiborÒ 2000 channels absorbed less energy than the UsiborÒ 1500. Numerical simulaRons of three-point bend tests were completed with homogenous, symmetric and asymmetric channel tailoring configuraRons. These were run quasi-staRcally at 10mm/min and dynamically at 10m/s, and force-displacement responses were produced for validaRon against the experimental results. The symmetric and asymmetric tailored channels were predicted to behave similarly to the homogenous channel matching the quench condiRon of their center zone. The validaRon metric values represenRng variance between predicted and experimental force-displacement responses were 0.865 for UsiborÒ 1500 and 0.828 for UsiborÒ 2000 (excluding fracture) where unity is an exact match.