Two-level Method Of Subproblem Approximation Method And Improved Simplex Method And Its Application In The Optimization Of Flare Boom Truss

As flare boom truss gets the influence of gravity as well as wind load in the sea In the work,static and dynamic response of the structure become complicated.So that optimization of flareboom truss is very important.Subproblem approximation method of ANSYS makes objective function and state variablesapproach to criticality value by a random search, so it is suitable for global search. It needs largespan. When objective function achieves tolerance, the process stops and the result is non-optimalvalue. Improved simplex method of gold segmentation algorithm uses variable step to search.The process is faster with big step, but the accuracy is worse. The accuracy is better with smallstep, but the number of search increases and the optimization speed slows. Improved simplexmethod of small step is suitable for partial search. This paper firstly uses the two-level method toachieve the optimizatioan of flare boom truss. This two-level is done as follow: use thesubproblem approximation method of ANSYS to get the searching field of flare trussoptimization small, and then use the improved simplex method to further search during the patialfield to get the better results.Design variables of more influence on the objective function were selected by sensitivityanalysis. The weight and the first-order frequency are optimized by the two-level method to savematerial and cost and avoid vibration. The first level is Subproblem approximation method ofANSYS, the second level is improved simplex method. The structure after optimization is morewind resistance and safer in the sea. This gives a reference for optimization of complexengineering structure.