Nonlinear Analysis And Section Optimization Design Of Steel-Wood Composite Columns Under The Eccentric Compression

The steel-wood composite column is a new type of prefabricated combined member.The steel plate is the main bearing component,and the board provides lateral stiffness for the combined member.With high bearing capacity the steel is easy to be buckling and instability.The combination of the steel and the wood slab can give full play to their advantages and make up for their shortcomings.Therefore,with the characteristics of high strength and good stability,the steel-wood composite column has a wide application prospect.Some researches on composite members have been carried out at home and abroad,but the theoretical research on nonlinear analysis of steel-wood composite members is still incomplete.Therefore,it is of far-reaching significance to carry out the nonlinear whole-process analysis of steel-wood composite columns.Prefabricated components have been widely used in urban construction in China.Optimizing the section size of the steel-wood composite members not only reduces the project cost,but also has important implications for the popularization of steel-wood composite members in practical engineering.The main work and conclusion of this paper are as follows:Firstly,according to the existing eccentric compression tests of the steel-wood composite columns,based on the reasonable constitutive model of H-section steel and wood,the force balance equation and bending moment balance equation of the section of steel-wood composite columns are established.The whole process analysis and calculation program of steel and wood composite column section is coded in MATLAB,and the relationship curves of the bending moment and the curvature are obtained.At the same time,based on the whole process analysis of the composite column section,the program for the nonlinear whole process analysis and calculation of the steel and wood composite column members are coded,and the ultimate load and deflection of the composite columns are calculated.By comparing the calculated values with the experimental results,the error is within the allowable range,which indicates that the theoretical calculation method of the whole process nonlinear analysis of steel-wood composite column is feasible.Secondly,combined with the existing tests,finite element analyses are carried out on the steel-wood composite column in ABAQUS software,and the load-deflection curves are obtained.The finite element analysis results fit in well with the experimental results and the theoretical results,indicating that the finite element modeling can replace the experiment to simplify the analysis of the steel-wood composite column to a certain extent.Thirdly,basing on the finite element models,the influence of four cross-section parameters on the mechanical properties of the steel-wood composite column is studied.The analysis shows that the height of H-beam webs is the most important cross-section parameter,followed by the thickness of H-beam flange,larch board and H-beam webs.The analyses show that the height of the H-beam web has the greatest influence on mechanical performance,followed by the thickness of the larch plank,the thickness of the H-beam flange and the thickness of the H-beam web.Fourthly,the height of H-beam web,the thickness of the web,the thickness of the flange and the thickness of larch plank are used as the design variables.The maximum deflection of steel-wood composite column,the maximum stress of the H-beam and the maximum stress of the larch plank are taken as state variables.And the cost of the composite column is taken as the objective function.The parameter analysis and parameter optimization control files are compiled by using the structure size optimization algorithm in ABAQUS parametric design language and the section of the steel-wood composite column is optimized.After the optimization,the optimal section design scheme of the composite column is obtained.The height of H-beam web is 177.86mm,the thickness of the web is 6mm,the thickness of the flange is 6mm and the thickness of larch plank is 43.91mm.The cost of the composite column is reduced from 1196.88 RMB to 641.93 RMB.The optimal section design scheme saves 554.95 yuan,whose cost is only the 53.63%of the initial cost,indicating the high efficiency and the significant optimization effect of the optimization method.