Stress Constrained Topology Optimization Comparing Global and Local Approaches

Sammanfattning

In several industries, components that are both lightweight and meet strict requirements need to be manufactured. Structural optimization is an approach, which follows these requirements to be formulated mathematically. This master´s thesis in concerned with density based topology optimization with the goal of minimizing structural compliance (maximizing stiffness) under both volume and stress constraints. Two types of stress constraints are studied. A global constraint that approximates the maximum von Mises stress in the structure, versus fully local constraints applied to each finite element, which often in topology optimization leads to problems with thousands to millions of constraints in contrast to the global stress constraint requiring only one. The method is based on solid isotropic material with penalization, to link densities to material properties, while the design variables are updated with the method of moving asymptotes. The study compares global and local stress constraints in terms of their ability to manage local stresses and overall structural compliance. The results shows the global stress constraint performed effectively, while local stress constraints are preferred in safety-critical applications requiring strict stress control. However, the result also indicate that both approaches require further tailored implementations to solve specific problems.