Robust optimization of coupled structural-acoustic systems based on sensitivity analysis

An interval finite element method and an interval robust optimization model were proposed for the coupled structural-acoustic field prediction and structural design with uncertainties both in the inherent parameters and external load. Based on the central difference method, the response sensitivity with respect to the system parameters was derived from the structural-acoustic dynamic equilibrium equation. Interval variables were used to quantitatively describe all the uncertain parameters with limited information. In terms of the first-order Taylor expansion, the lower and upper bounds of the uncertain structural-acoustic field could be quickly obtained. In the structural robust optimization, the original uncertain single-objective optimization problem was transformed into a deterministic multi-objective one by introducing a sensitivity index. To ensure a more stable performance of the structural design, the interval possible degree was adopted to describe the robustness of the constraints. Numerical results about a bomb bay were given to demonstrate the effectiveness of proposed robust model and algorithm.