Session: 03-20-02: Manufacturing: General

Paper Number: 144731

144731 - Energy Absorbing Analysis and Deformation Mode Comparison of Traditional and Additively-Manufactured Crush Tubes 

Thin-walled axial crushing members, or crush tubes, are often utilized as energy absorbers due to their high strength to weight ratios. Applications of such devices include automotive, aerospace, and structural components. Core materials such as graded honeycomb or other support members have shown to greatly increase energy absorbing capacity, while improving structural stability during deformation or collapse. The ideal performance of such members through axial crushing exhibits numerous stepwise collapse mechanisms, or folding, up to complete exhaustion of the structure. The total capacity of these structures is highly dependent on the number of folds present during collapse. The present study aimed to compare traditional axial crushing members with graded cellular cores to those made through an additive manufacturing (AM) process. Optimization strategies included: decrease in component mass while meeting or exceeding previous energy absorbing performance. This study was conducted through a numerical approach using ABAQUS/Explicit dynamic modeling environment. The tube was modeled as a deformable shell geometry with 3 mm wall thickness and overall length of 355.6 mm (14 in.). The cross-sectional geometry of the tube was a constant 76.2 mm (3 in.) square from the impact end to the distal end. Additionally, the graded cellular core was modeled as an extruded shell and was manipulated to fill the internal void of the tube. Discrete rigid planar structures were affixed to both ends of the tube to provide impacting and support bodies for the tube structure. Fixed/encastred boundary conditions were assigned to the base support plate and displacement/rotation constraints were assigned to the impact plate to restrict displacement in the impact direction. A 600 kg reference mass was assigned to the impact plate with an initial velocity of 15.6 m/s (35 mph). Material properties were assigned to the traditional tube (A36 steel) with a cellular core (6061 Al) and to the AM tube and core (AM Al), both with general contact properties and frictional loss penalty definitions. Numerical analysis was performed until densification of the structure and numerical outputs were analyzed for crushing force, plateau stress, deformation modes, and total energy absorption for each tube and the results compared.

 

Presenting Author: Sean Jenson Ohio University

Presenting Author Biography: Sean Jenson is an Assistant Professor in the Mechancial Engineering Dept. at Ohio University.

Authors:

Sean Jenson Ohio University
Ian Switzer Ohio University
Muhammad Ali Ohio University
Brian Wisner Ohio University