STRESS-BASED TOPOLOGY OPTIMIZATION

Previous research on topology optimization focussed primarily on globa l structural behaviour such as stiffness and frequencies, However, to obtain a true optimum design of a vehicle structure, stresses must be considered. The major difficulties in stress based topology optimizati on problems are two-fold. First, a large number of constraints must be considered, since unlike stiffness, stress is a local quantity. This problem increases the computational complexity of both the optimizatio n and sensitivity analysis associated with the conventional topology o ptimization problem. The other difficulty is that since stress is high ly nonlinear with respect to design variables, the move limit is essen tial for convergence in the optimization process. In this research, gl obal stress functions are used to approximate local stresses. The dens ity method is employed for solving the topology optimization problems, Three numerical examples are used for this investigation. The results show that a minimum stress design can be achieved and that a maximum stiffness design is not necessarily equivalent to a minimum stress des ign.