Time-variant reliability-oriented structural optimization of series systems

摘要

A method for solving time-variant reliability-based optimal design problems for series of structural components via the outcrossing approach is presented. A one-level optimization is proposed by adding the first-order Kuhn-Tucker optimality conditions for the design points of the series system reliability problem as constraints to the cost optimization problem using first order reliability methods (FORM) in standard space. The extension of this method to separable (independent) time-variant series systems is shown. Separability allows to fulfil all componental Kuhn-Tucker conditions simultaneously for all components at the expense of an enlarged space. Each failure mode can have its own reliability constraint and limit state function. Expected cost of failure can also be included, if necessary separately for each failure mode. Two different locally stationary load models, rectangular wave renewal and differentiable Gaussian processes, are used. Some algorithmic details are discussed. The approach is demonstrated at two examples.