Robust design of composite structures based on minimization of uncertainty effects

Abstract

Structural applications of composite materials have increased due to their excellent specific stiffness and low weight together with reduced energy consumption. Variations of manufacturing process parameters and environment aspects may affect quality and performance of the product with consequences to its structural behaviour. Robust design optimisation (RDO) searches for safe structural systems with minimal variability in the response when subjected to uncertainties at the input parameters. RDO pursues two main objectives: keeping at an acceptable level the variations of the structural performance and controlling the magnitude of uncertainty at the input parameters. To search RDO of composite structures an analytical robustness assessment is performed based on sensitivity analysis and optimisation. A bi-objective optimisation is performed considering the following objective functions: 1) a function which describes the performance of the system and their relationship with corresponding targets; 2) a function which describes the robustness of the system related with gradients of all functional intervening in the process weighted by its actual value. At the end of the optimisation process the Pareto front representing the frontier of the trade-off between the "performance" and the "robustness" functions is obtained. This bi-objective optimisation is a powerfully tool to help designers to make decision establishing the priorities between performance and robustness.