Advanced Analysis Theory Of Steel Structure In Three Dimension Space And Its Application

Compared with conventional steel structure designing, the thesis tries to accomplish steel structural strength checking, integrate buckling analysis and local buckling analysis by one-step structure analysis . Based on the nonlinear finite element theory, the author has compiled an advanced analysis software--XJDAAST-H, which has partially passed identification that was presided by the Steel Structure Association of Construction Ministry which was entrusted by ShanXi province Education Office, and has been successfully used to design a structure which is a single layer shell in the sphere screen of ShanXi Province Nature Museum, and at the same time has done two correlative structure experiments.The thesis firstly and systematically develops the three dimension space steel structure advanced analysis theory study, deeply explores the elastic-plastic-zone analysis theory, gets the satisfied stress analysis results, puts forward the designing method considering the local buckling effective of steel components in integrate analysis, and initially abandons the restriction of plate width-thickness ratio. Based on the theory of the thesis, the author compiles a program (XJDAAST) which has some certain innovation in theory depth compared with the same kind of steel structure application program. The validity of theory and program has been verified by test example and practice project.In the part of theory analysis and software compiling, based on three-dimension space integrate structure and thin-wall structure theory, the thesis includes the following five parts:(1) The thesis begins with the virtual displacement principle based on the updated-Lagrange formula, firstly takes the solution of differential equation of pulK press and bending component as the shape function, and derives three dimension beam-column element's stiff matrix in which the author takes the influence of intersection warping into account on the basis of Bernoulli bending plane-section premises and Vlasov's torsion theory and breakthroughs the malpractice which takes the interposition-function as the shape function and does not reflect the real deformation of steelcomponents.(2) The thesis establishes the plastic-zone analysis model of three dimension space steel structure and firstly considers the constitutive relation based on isotropic damage , Von Mises yielding condition, Zeigler mixed hardening and correlation flow principle.(3) The thesis puts forward the designing method considering the local buckling effective of steel components in integrate analysis and initially abandons the restriction of plate width-thicknessratio. The author firstly uses space shell elements to partition the steel components, the uses the substructure-method to assemble the shell elements into a thin-wall structure component for participating in the integrate structure analysis. In this part, the author uses the Frey and Morris's polynomial model to model the property of semirigid connection, derives the double nonlinear element stiff matrix of 16 nodes shell element, condenses the inner degree by the inner eliminating law, and coordinates the outer degrees by he Bernoulli plane-section premise and Vlasov warping premise.(4) Based on the nonlinear finite element theory, the author has compiled an advanced analysis program -XJDAAST-H which is more special and convenient than the foreign program Ansys and Sap2000, has some certain innovation in theory depth compared with domestic steel structure application program, and adequately considering the special property of steel components. The validity of theory and program has been verified by a number of test example and Ansys results. The program can be used to track the limit load and flex point of space structure, can take structural imperfection into consideration, gets the buckling model and vibration model of three- dimension steel structure, analyzes the elastic-plastic status or stress distributing of any intersection and any point and draws the nephogram of stress distributing, the hystere...