Local Finite Element Refinement for Accurate Dynamic Stress via Modal Information Only

Abstract

Accurate stress responses are the basics for failure analysis of aerospace structures, but they still can be challenging in numerical simulations for dynamic systems. This work exploits the stress mode shapes (SMSs) in local finite element (FE) refinement for the purpose of accurate dynamic stress estimation. Toward structural FE modeling, identification of critical locations via predominant SMSs is theoretically demonstrated. To pursue more accurate dynamic stress, a strategy for local FE refinement is proposed by using the information from stress modal analysis. The strategy involves a two-step procedure. First, modal participation factors (MPFs) are used to extract the predominant modes. Second, retained SMSs are evaluated for the local remeshing. Numerical simulations of a representative thin plate with geometric details were conducted. The SMSs were investigated in detail. Together with MPFs, SMSs can help to localize the dangerous stresses and then refine the local meshes to accurately calculate stress responses. By taking full advantage of numerically obtained SMSs, local structural FE modeling can be applied in a straightforward way with high efficiency. Results indicate that SMSs can reveal the underlying mechanism that governs the overall dynamic stress response.