Effective structural sizing/shape optimisation through a reliability-related multifactor optimisation approach

Purpose - The aim of this paper is to present a novel multifactor structural optimisation method incorporating reliability performance. Design/methodology/approach - This research addresses structural optimisation problems in which the design is required to satisfy multiple performance criteria, such as strength, stiffness, mass and reliability under multiple loading cases simultaneously. A MOST technique is extended to accommodate the reliability-related optimisation. Structural responses and geometrical sensitivities are analysed by a FE method, and reliability performance is calculated by a reliability loading-case index (RLI). The evaluation indices of performances and loading cases are formulated, and an overall performance index is presented to quantitatively evaluate a design. Findings - The proposed method is applicable to multi-objective, multi-loading-case, multi-disciplinary and reliability-related optimisation problems. The applications to a star-like truss structure and a raised-access floor panel structure confirmed that the method is highly effective and efficient in terms of structural optimisation. Originality/value - A systematic method is proposed. The optimisation method combines the MOST technique with a RLI (a new alternative route to calculate the reliability index at multiple loading cases) using a parametric FE model.