Energy-absorbing And Numerical Study On Light Weight Thin-Walled Metal Structures

Energy-absorbing, thin-walled, impact-resistant metal structures have been widely used in aircrafts, automobiles, trains and ships and other transportation apparatus as the parts of energy dissipation of impact kinetic energy. Therefore, extensive attentions have been drawn on performance investigations of energy absorption of various forms of thin-walled metal structures.This thesis is funded by The National Science Foundation of China (Projects 10332010, 10721062) and The National Basic Research Program of China (Project 2006CB601205).The light-weight, thin-walled metal structures are studied in this paper. A new type of energy -absorbing structure is proposed to investigate the structural deformation mechanism and energy absorption under transient axially compressive impact loadings.The research work can be summarized as follows:(1) System description and analysis of theoretical models of cylindrical metal shell under axial compressive loadings, and numerical simulations for three thin-walled metal structures possessing the same cross-sectional areas loaded by transient axial pressures. The patterns of deformation and performances of energy absorption are compared and analyzed, respectively.(2) Numerical simulation for complicated energy absorption of a truss- reinforced sandwich-type cylinder tube with large displacement and large strain. The numerical model is established based on the nonlinear finite element theory. The property of energy absorption under axial impact loadings is investigated with the proposed model. Various impact speeds and internal truss layouts are used to study how they affect the capability of energy absorption of the compound tube. The numerical results present a valuable reference to design light weight composite structures with the best performance of energy absorption under impact circumstance.(3) Numerical modeling of a cylinder tube with a finite length of crack is presented based on the fracture mechanics theory with an appropriate criterion for fracture. The deformation and damage are predicted and numerically analyzed considering nonlinear transient axial compressive loadings.