Robust Design Methods. Aircraft Design Study

Robust Design is an engineering methodology intended as a cost-effective approach for improving the quality of product and processes, which was proposed in mid 1980s by Genichi Taguchi. The assumption is that there are both controllable factor and uncontrollable factors (noise variables) that operate on the quality characteristic of a product. The Fundamental principle of Robust Design is to improve the quality of a product by minimizing the effect of the causes of variation (noise variables) without eliminating the causes. This paper studied the two Robust DesignMethods--Taguchi Method and Response surface method to Robust Design andtheir applications in aircraft design.The first part of the paper improved the Classical Taguchi method to solve constrained optimization problem. Using the improved Taguchi Method, this paper solved the Robust Design of the composite laminated plates subjected to an in-plate loading which was assumed to be normal distribution. The performance of the robust composite plate is insensitive to the variation of the loadings.The second part of the paper summarized the Response surface method to Robust Design. Then we studied the problem of the airfoil optimization for discrete operating conditions which may result in dramatically inferior performance when the actual conditions are different from the given design value (off-design). To overcome the off-design degradation, we construct a robust airfoil optimization Method base on response surface method. This method reduced drag over a given range of operating conditions and kept the performance fluctuation as low as possible by minimizing the mean and the variance of the drag coefficient over the range of operating conditions and it was verified useful and efficient by solving a lift constrained drag minimization problem for a tow-dimensional (2-D) airfoil in transonic viscous flow with Mach number as the uncertain operating condition.