Finite element analysis of thin-walled structures subjected to impact loading

This thesis is devoted to the numerical solution of dynamic problems involving thin-walled structures. Special consideration is paid to the effects of contact-impacts. Thus, the main effort is concentrated on studies, development and computer program implementations of efficient algorithms for analysis of dynamically loaded shell structures, including contact-impacts and severe structural deformation. Recent developments in the formulation of efficient finite elements for dynamically loaded shell structures are studied. A program implementation of a low-order four-node shell element with uniformly reduced integration is performed. The efficiency and the behaviour of this element type are compared with existing shell and solid elements implemented in the same program system. Hourglass resisting algorithms are reviewed and formulated, and parameter studies are carried out. A new contact interface algorithm for dynamic analysis with explicit integration is presented. The development of the defence node algorithm permits contact constraints based on the Lagrange multiplier method to be introduced in dynamic analysis with explicit integration. Numerical tests show the good performance of the developed algorithms. A new global search method for general contacting systems is developed and implemented in a computer program together with the abovementioned contact interface algorithm. The concept of position codes for efficient global contact searching and the local search procedure used are presented. Numerical experiments are performed in order to examine the behaviour of the algorithms in different aspects.Godkänd; 1988; 20070424 (ysko