A NUMERICAL INVESTIGATION OF WAVELENGTH AND BOUNDARY CONDITION OF AXISYMMETRIC COLLAPSE OF CYLINDRICAL TUBES

This is a dissertation research in that after some reviewing past works on mechanical energy absorbers: plastic folding of cylindrical tubes under axial loads is analysis using a finite element method of crushing process by LS-DYNA software . results of displacement of controlled crushing models are presented on tubes of various radiuses to thickness rations with the same other characteristics. Collapse in cylindrical tubes like other shapes of absorbers varies depending on dimension, boundary condition and materials but we chose the parameters so that axisymmetric progressive crushing can occur in all case. Boundary condition effect on energy absorption capacity of structure in investigated assuming constant rate of load. Two famous models taken from the literature which steady-state folding is modeled by kinematical admissible collapse mechanisms called Alexander and Wierzbicky’s theoretical models are also reviewed and at last the obtained length of folds in simulated modes are compared with them.

کلیدواژه ها:

Cylindrical tubes ، Simulation ، Folding ، FEM ، Energy absorber ، Impact absorber