Citation

Salehghaffari S, Panahipoor M, Tajdari M. Int. J. Crashworthiness 2010; 15(3): 251-264.

Copyright

(Copyright © 2010, Informa - Taylor and Francis Group)

DOI

10.1080/13588260903209099

PMID

unavailable

Abstract

In the present study, combination of axial crushing and expansion mode of deformation in a single tube is shown to be an efficient energy-dissipating candidate. In this energy-absorbing method, a rigid expanding ring is press fitted on top of a cylindrical tube. When this arrangement of dissipating energy is subjected to axial compression, the rigid ring is driven into the cylindrical tube and expands its top area since there is specific interference between them; then, as compression of the shock absorber continues, plastic folds start shaping along the rest of the tube length. In the present study, an expanding steel ring is press fitted on top of seven aluminium alloy AA6060 tubes of 2.5 mm thickness and 70 mm inside diameter in different lengths of 200, 300 and 350 mm, and these specimens are compressed quasi-statically. The length of rigid ring is considered as a parameter in these experiments. To understand the effects of press fitting an expanding ring on energy absorption characteristics of aluminium tubes, three specimens without the expanding ring in different lengths are also compressed quasi-statically. Results show that application of the expanding ring prevents moderate global bending of specimens of 300 mm length and extreme global bending of specimens of 350 mm length. Also, it is observed that quasi-static compression of specimens with expanding rigid ring results in greater values of stroke length. Results show that application of the expanding ring encourages progressive collapsing of the experimented specimens, and improves their crashworthiness characteristics significantly. In this paper, to study the collapsing and energy absorption behaviour of the shock absorber in detail, numerical simulations of a specimen's collapse under quasi-static compression using ABAQUS 6.4 are also carried out. It is found that there is a good agreement between numerical and experimental results.