DESIGN SENSITIVITY ANALYSIS METHOD FOR MULTIDISCIPLINARY SHAPE OPTIMIZATION PROBLEMS WITH LINEAR AND NONLINEAR RESPONSES

A method to solve shape and size optimisation problems with linear and non-linear responses has been studied taking advantage of statistical methodologies. A nested optimisation procedure has been fixed The glo bal optimisation problem is decomposed in several subproblems where ea ch non-linear response is locally approximated with a first degree pol ynomial function identified by the definition and execution of an expe rimental plan. The approximating functions so obtained are used to eva luate the design sensitivity coefficients required by the optimisation procedure. The numerical results obtained during the optimisation pro cess to verify exactly the value of the non-linear responses are used to verify and to improve the approximating function accuracy. The non- linear design sensitivity analysis method so defined has been used to solve a multidisciplinary shape optimisation problem involving a real 3D automotive structure.