Enhanced Predictive Model for the Mechanical Response of Compression-Loaded Slender Structures

The study of the behavior of thin metal sheets subjected to external loads has always been a matter of great interest due to its numerous theoretical and practical implications. The present analysis aims to investigate how to improve the predictions offered by a numerical model based on the finite element method by considerations on the material properties. Specifically, different modeling alternatives are compared, assessing these choices both with the similar assumptions made by other researchers in the past and with measurements from our own experimentation. The case under consideration consists of a slender, aluminum crash-box structure (a bumper) with a truncated pyramid shape subjected to a concentrated load on the top (axial crushing) up to a 46% reduction in its height. The system is characterized by high deformations (>15%) and large displacements. This presents a complex situation with various nonlinear effects, where the chosen assumptions in material modeling can have significant implications for the results, both in terms of accuracy and computational time. Among the investigated aspects, of no less importance are those related to the appropriate modeling of the elasto-plastic-hardening behavior of the metallic material.