Structural topology optimization considering multiple performance criteria reliability (for cases where variation of element cross-sectional property is considered)

Abstract

This paper describes a reliability based topology optimization for frame structures, which includes variations of element cross sectional properties in the random variables as well as applied loads and nonstructural masses at the early conceptual design stage. This enables the evaluation of the effect of varying structural properties in the structure, so that more useful reliability based optimum topology designs can be obtained for multiple performance criteria, namely, stiffness and eigenfrequency. The system reliability is obtained by modeling both criteria as a series system and the mode reliability is evaluated using the first order reliability method (FORM). Then, the topology design maximized for reliability is evaluated under a total volume constraint in terms of mean cross sectional area of each element, using the convex linearization method (CONLIN). Through numeri cal calculations, reliability based topology designs of typical three dimensional frames are obtained The obtained optimum topology is explained from the dominant mode reliability and the deterministic optimum topologies. Also, the effect of the variation in cross sectional properties on the reliability is investigated from the design point.