SHAPE OPTIMIZATION OF SHELL ROOFS SUBJECTED TO STRONG WIND BY USING A VARIABLE COMPLEXITY MODEL

摘要

Optimal shapes are found for a shell structure subjected to strong wind. The air flow around the shell is computed by finite element non-stationary analysis to determine the time-history pressure distribution against the roof, where the fluid-structure interaction is neglected. The shape of the roof is to be optimized to minimize the deformation under wind load. A Variable Complexity Model (VCM) which consecutively solves 2-dimensional and 3-dimensional problems is presented to reduce the computational cost in the optimization process. The shape of the shell is modeled by a Bezier surface, and the design variables are the locations of the control points. Since the sensitivity coefficients of the responses are not smooth with respect to the design variables, an approximate solution is found by a response surface method. It is shown that similar shapes can be found by VCM and 3-dimensional analysis, and a slightly asymmetric shape is very effective for reducing the deformation under wind loads.