Minimum-weight design of compressively loaded stiffened panels for postbuckling response

A computationally efficient procedure, NLPANOPT, is developed for the optimal design of thin-walled stiffened composite panels loaded in uniaxial compression based on a geometrically nonlinear analysis. An approximate, semi-analytical nonlinear analysis code NLPAN, which requires buckling eigenfunction information from the buckling analysis code VIPASA, has been linked with the optimization code ADS. To demonstrate the capabilities, a blade stiffened panel is designed using NLPANOPT. For the same configuration, optimal designs based on a linear analysis are obtained using the design code PASCO. Comparisons of panel weight and imperfection sensitivity between the linear designs and nonlinear designs are made. In general, the designs that are obtained based on the nonlinear analysis are lighter and less imperfection sensitive.