On axial splitting and curling behaviour of circular sandwich metal tubes with metal foam core

Axial splitting and curling behaviour of circular sandwich metal tubes with metal foam core is investigated analytically and experimentally. The sandwich tubes split axially and the strips curl outward by prefabricated cracks at the distal end of the specimens. Axial compression experiments of circular sandwich metal tubes are carried out and deformation modes are found. A theoretical model is developed to predict the axial splitting and curling behaviour of the circular sandwich metal tubes including effects of the tearing of the cracks, plastic bending, curling, foam compression and friction. It is shown that the analytical predictions capture the experimental results reasonably. Effects of the tube thickness, foam strength, foam thickness, the number of the prefabricated cracks, and the semi-angle of the die are of vital important in energy absorption devices by the axial splitting and curling of circular sandwich tubes. (C) 2020 Elsevier Ltd. All rights reserved.