Ultimate Bearing Capacity Of I-Section Thin-Wall Beam Structure Based On Homogeneous Generalized Yield Function

At engineering, the application of open thin-walled bar become more and more widely, the study of the ultimate bearing capacity is also more and more important. The Elastic Modulus Reduction Method (EMRM) has been proposed rencently, established a modulus adjustment strategy, base on the generalized yield criterion, then imitate the structure failure process.This paper takes thin-walled bar structure as the research object, and considering the bend torsion in calculation of ultimate bearing capacity, to carry out the generalized yield criterion research with the thin-walled been features, and put into the EMRM. For this reason, make the EMRM using range expansion. The main contents of this thesis are as follows:(1) With thin-walled bar theory, the use of Hermite functions to establish a local unit displacement field, the establishment of open thin-walled bar restrained torsion total potential energy functional. One dimensional finite method used to derive the thin-walled bar opening in complex load (tension and compression, transverse bending force, restrained torsion) of the element stiffness matrix for the static calculation of thin-walled bar openings.(2) For the I-shaped thin-walled members, and least squares regression analysis to derive the internal force established to consider all seven of homogeneous generalized yield function, to overcome the traditional non-homogeneous generalized functions from the root yield bomb plastic adjustment flaws in the analysis. In order to eliminate the initial load multiplier impact on the results of ultimate load analysis purposes.(3) Based on this article Homogeneitisation fitting generalized yield criteria, combining the theoretical limit and plastic limit analysis of the elastic modulus adjustment method, a numerical analysis model is derived to calculate Shaped ultimate bearing capacity of thin-walled structures. In this paper, the establishment of the elastic modulus adjustment method, the elastic modulus of the scope of the expansion of the adjustment method to achieve the I-shaped thin-walled members under complex loads of plastic limit capacity analysis. Plastic limit for thin-walled bar structure provides a new way of thinking and a new method to analyze and expand the application of the elastic modulus reduction method.(4) The established EMRM the mesh density, capacity and poor convergence parameter sensitivity analysis and calculation parameters are given values proposed, and with elastoplastic Act (EPIA) sensitivity analysis of the parameters comparison. This method compared with other methods EPIA, while easier to use, it could also take into account the computational efficiency and accuracy.