Research On Section Optimization Of Portal Frame Based On Improved Genetic Algorithm

The portal frame structure is widely used in industrial buildings,the design of the portal frame is generally based on the design experience,the section type and section size of the component are preliminarily selected,and then the bearing capacity,stability and deformation are checked,that is to complete the design,generally do not compare and optimize the program.Due to the designer's design level and design experience gap,when different people in the same project are designing,the amount of steel used in the structure may vary greatly.Therefore,the research on the optimization design of the portal frame structure,looking for a more intelligent design approach,design tools for optimal design of portal frame structures,it is of great significance to reduce project cost,save resources and reduce the workload of designers,the main research contents and conclusions of this paper are as follows:(1)Based on the finite element method,the stiffness matrix of the component element and the equivalent node load matrix are solved,the overall stiffness of the portal frame and the equivalent node load matrix are obtained by the unit integration method,the mechanical analysis model of the portal frame is established.(2)With the design limits of bearing capacity,stability and deformation of each component as the constraints,the steel section type and section size parameters are used as design variables,and the total steel quantity of each component of the portal frame is taken as the objective function to establish the gate type,rigid frame section optimization model;(3)The population coding method and genetic operator of genetic algorithm are improved.The improved genetic algorithm main program is programmed by MATLAB software,and the subroutine based on niche technology is programmed,and the finite element method portal frame mechanics analysis calculation subroutine,it is nested into the main program,an automatic search optimization program for portal frame based on improved genetic algorithm is formed,which can realize collaborative search of component section type and section size.(4)The PKPM software is used to verify the optimization results of the portal frame based on the improved genetic algorithm.The optimization results meet the requirements of various constraint limits,at the same time,the optimization results of this paper are compared with the STP-PK cross-section optimization results in PKPM software,the optimized method saves 4.98% of steel and the optimization effect is better.(5)The GUI toolbox in MATLAB is further used to complete the software design of the portal frame cross-section optimization,and the design tool is provided for the optimal design of the portal frame structure.