Optimization design of steel vierendeel truss structure based on response surface method
To improve the optimization design efficiency of steel vierendeel truss structure,a structural optimization design method based on the response surface method was proposed to optimize the design of steel vierendeel truss.Before optimization,the equivalent inertia moment and equivalent shear stiffness of the vierendeel truss were derived according to the virtual work principle,and the accuracy of the finite element model was verified by the equivalent beam flexibility method.Through the Box-Behnken experimental design,totally 66 groups of finite element test samples were obtained,and Kriging response surface was established to obtain approximate response points.With the goal of minimizing structural quality and the constraints of maximum allowable combined stress,maximum deflection,and component width to thickness ratio,the MOGA genetic algorithm was used to optimize the design of the vierendeel truss,and the Pareto optimal candidate solution was obtained.The results show that under all levels of loads,the maximum relative error between the finite element calculation value and the equivalent stiffness method calculation value is only 5.6%,which verifies the accuracy of the finite element model used for optimization design.The optimal steel consumption of the three groups of candidate solutions after optimization is 6 195.4 kg,which saves about 18%of the steel consumption compared with that before optimization.The geometric parameters related to the optimal solution are verified by finite element numerical tests.The width to thickness ratio,maximum combined stress,maximum deflection and structure quality of the optimized members are in good agreement with the numerical test results,and the deviation is within 3%,which shows that the structural optimization design method based on response surface method is suitable for the multi-parameter optimization design of steel vierendeel truss structures.