Dynamic collapse of circular metal foam core sandwich tubes in splitting and curling mode

This paper investigates the dynamic collapse of circular metal foam core sandwich tubes in splitting and curling mode subjected to low-velocity impact. The splitting and curling modes occur along the prefabricated cracks on sandwich tubes. The deformation modes, i.e. crack propagation along the prefabricated crack, new crack initiation, merging old cracks are observed in experiments. It is found that the number of strips in the sandwich tube tends to develop from the number of prefabricated cracks to the number of steady strips. Based on the principle of minimum energy, the method for predicting the number of steady cracks in the inner and outer tubes of the sandwich tubes is established. The quasi-static analytical model is approximately used to predict experimental results, and analytical results capture experimental ones reasonably. It is demonstrated the better energy absorption characteristics can be obtained by the proper thickness of metal foam core.