6th World Congresses of Structural and Multidisciplinary Optimization

In the optimization process of a complex three-dimensional continuum structure by using the conventional evolutionary structural optimization method, some isolated groups of elements or a few elements being of rigid movements, often appear in the optimized structure, which becomes singular so that the optimization process can’t continue. In order to overcome this problem, this paper proposes an improved evolutionary structural optimization method for topology design of three-dimensional continuum structures with a stress uniform requirement. In the proposed method, a few of finite elements with artificial material property are added around the cavities and boundaries of the current structure to approximately transform the singular topology optimization model into a non-singular one, an idea is proposed that all datum information in the optimization process of a structure are grouped as a set of structural optimization datum flow and a set of structural characteristics computation datum flow, and a simple transferring procedure between them is given. Because there not is any ill phenomenon in the global stiffness matrix of the new transferred structural model, an iteration solving method is adopted in structural nodal displacement computations. Element addition and deletion are based on Ishai stress criterion. Continuum structures constructed with isotropic material and tension/compression dominant material can be optimized by the proposed method. Two examples of typical and complex three-dimensional continuum structures are given. It is demonstrated that the proposed method is very effective in generating optimal topology designs of complex three-dimensional continuum structures that are modeled using more than several ten thousands of brick elements.