Progressive axial crushing behaviour of Al6061-T6 alloy tubes with geometrical modifications under impact loading

Abstract

Axial crushing of tubes with multiple patterns of cut-outs is studied using numerical analysis. Commercially available finite element ABAQUS/Explicit® package is used to simulate the model under impact loading condition. Split-Hopkinson Pressure Bar (SHPB) is modelled to dynamically test the tube specimens with and without cut-outs. Number, size, and shape of cut-outs are kept constant in all specimens to have a constant weight reduction. In order to improve the crashworthiness characteristics of tubes, cut-outs are arranged on a tube surface along the circumferential and longitudinal direction in multiple rows. Crashworthiness parameters i.e., peak and mean collapse load, crushing efficiency, energy absorption characteristics are studied. The results revealed that a moderate weight reduction of tube can significantly affect the crushing characteristics of tube. In terms of load characteristic values, only 1% of weight reduction in modified tube samples has helped in 4.46% peak load reduction as compared to the normal tube, and crushing efficiency of the modified tube (T2) is found to be 2.17% higher than normal tube (T). In terms of energy absorption characteristic values, 1% of weight reduction in modified tube samples has helped in 1.95% reduction in energy absorption capacity as compared to the normal tube, and energy efficiency of modified tube (T2) is found to be 2.56% higher than the normal tube (T). After arranging the cut-outs in a multiple pattern, the location of cut-out is also seen to be influencing on the tube behaviour. It helps the tube to reduce the initial peak collapse load and optimize the mean collapse load. Further, force–deformation characteristics are also discussed to improve the crashworthiness characteristics of tube under impact load.