Dynamic plastic behaviour of strain rate sensitive tubes under axial impact

In this paper, the axisymmetric buckling of circular strain rate sensitive tubes subjected to axial impact is investigated theoretically and experimentally. The nonlinear governing equations are first derived in an incremental form. Then, the finite difference method is employed to solve the obtained equations implicitly for the case when a stationary tube is impacted by a striking mass. Experimental tests are performed by using a gas gun. The effect of linear and multi-linear approximation for strain hardening and strain rate on the shortening, buckling shape and axial force of steel tubes are investigated in which the strain rate is considered as a function of time. By applying the strain rate effect and using the multi-linear approximation for strain hardening, we showed there is a significant association between theoretical and experimental results of steel tubes. Also, using the nonlinear dynamic equations and newly developed inexact finite similitude theory it is revealed that the response characteristics of full-scale strain rate sensitive tubes can be predicted using small-scale strain rate insensitive tubes.