A Comparative Study of Dent Resistance Incorporating Forming Effects

Dent resistance is an important attribute in the automotive panel design, and the ability to accurately predict a panel's dentability requires careful considerations of sheet metal properties, including property changes from stamping process. The material is often work-hardened significantly during forming, and its thickness is reduced somewhat. With increased demand for weight reduction, vehicle designers are seriously pushing to use thinner-gauged advanced high-strength steels (AHSS) as outer body panels such as fenders, hoods and decklids, with the expectation that its higher strength will offset reduced thickness in its dentability. A comparative study is conducted in this paper for a BH210 steel fender as baseline design and thinner DP500 steel as the new design. Forming effects are incorporated in the dent resistance analysis for both designs and results are presented to demonstrate the importance of considering forming effects in dentability simulation, especially for AHSS which tend to exhibit more rapid hardening than traditional steels. A detailed DOE study investigates effects of work-hardening, thickness-change, and bake-hardening on the denting simulation results. Important parameters affecting CAE denting results are identified, which in turn provides guidelines for production applications.