FE investigation of a spirally slotted tube under axially compressive static and dynamic impact loading

Abstract

In this study, helically gouged Steel tubes of relatively small thickness are discussed as a new design configuration for energy absorption, using the results of numerical simulations. The tubes are loaded in two different modes: Static compressive axial loading applied via a displacement and the kinematic coupling option of the FE code, which constrains the nodes at each end of the tube to the respective reference nodes. Dynamic axial impact loading via a mass element attached to the reference node of the rigid base platen which is energised by an initial velocity while appropriately maintaining its load sustaining resistance. One of the salient features of the deformation mechanism is that in both cases the axial shortening of the tube is accompanied by twisting. The boundary constraints of the reference nodes at both the loaded and supported ends are of significant importance and care has been exercised to specify the appropriate degrees of freedom for movement in both rotation and translation. The contact that occurs between various parts of the tube has been correctly identified and targeted. In the present study attention has been focused on the energy storage capacity of the model under both loading modes and in providing an explanation for the major differences in response that exist between the two cases. The material properties of steel are specified as linear elastic followed by non-linear work hardening in plastic range with moderate and high degree of sensitivity to strain rate effect. The solution reveals several important features, which are discussed in this paper. The proposed device could be used in clusters to limit damage in the event of cable failure in hoist & lift compartments. Although the procedure is applied to axial loading, the method is equally applicable to lateral static and impact loading as cited in the introduction.