Application of Plastic Collapse Mechanism for the Axial Crushing Analysis of Tubular Steel Structures Filled with Aluminium Foam

Abstract

In this work the suitability of simplified collapse models for the analysis of progressive buckling of axially compressed crush elements composed of steel tubes and aluminium foam are investigated. Based on a kinematics-oriented collapse mechanism for the progressive buckling of filled square tubes, proposed in the literature, adaptions are described that allow to investigate different types of cross-sections (square, hexagonal, octagonal), which are fully or partially filled with aluminium foam. The results of the parameter studies confirm the experimental observations that for given tube/filler combinations there exist optimal foam densities, leading to a maximum of the mass related energy absorption capacity of these tubular crush elements. It is shown that, despite all their shortcomings, simplified collapse models may at least be appropriate for quick preliminary design studies, allowing to qualitatively investigate the influences of the major design parameters on the overall response of foam filled tubular crush elements.