A novel Reliability Based Design Optimization method for truss and frame structural systems

A proper design procedure must consider various uncertainties. However, the expensive computational cost is the primary factor limiting application of RBDO on practical engineering. In this study, an efficient procedure for reliability assessment and its based optimization design of stochastic structural system are developed. First order method is adopted to calculate the safety indices since the safety margin equation is linear. Probabilistically dominate failure modes are selected by applying the branch-and-bound method. PNET is used to assess failure probability of structural system. The optimization design problem is formulated as a nonlinear programming problem to minimize weight with constraints on reliability and dimensions. The optimum vector algorithm is applied to solve the optimization problem under special convergence criterion. Two numerical examples are performed to illustrate the feasibility of proposed process for any novel truss and frame structure. The present optimization routine shows that the approach is efficient in the practical application.