Parametric structural optimization with respect to the multiaxial high-cycle fatigue criterion

Abstract

Investigations on optimization of structures working in high-cycle load conditions were carried out and are presented in this paper. The development of a simple in application optimization algorithm for such structures was the main object of the authors. The work was concentrated on three principle areas: fatigue of material (with special regard to multiaxial criteria of high-cycle fatigue), parametric optimization of structures, and application of the finite element method. The investigations and numerical implementation of several high-cycle criteria were made and the most convenient one for optimization was selected. The main process of fatigue optimization was preceded by the testing of methods of structural optimization and the preparing the tools for improving the efficiency of the optimization algorithm. This stage includes preparation of software tools based on evolutionary algorithms. In addition, the decision variables were preselected through an investigation of the sensitivity of the objective function on small increments of these variables. The work was illustrated by examples of optimization of mechanical structures working in high-cycle load conditions. As observed in the computational examples, the proposed methodology of optimization allowed effectively lowering the mass of the studied structure while maintaining its durability on an established level. The tools and fatigue optimization methodology presented in this paper have universal character and can be applied to any case of a structure subjected to high-cycle loads.