Analysis Of Ultimate Bearing Capacity Of High Strength Steel Axial Compression Members

In recent years,high-strength steel materials are more and more used in various practical engineering structures.Compared with ordinary steel,high-strength steel has the unique advantages of low economic cost,simple assembly and higher strength.High strength steel members can not only greatly reduce the section size,save the consumption of steel,but also reduce the construction time and shorten the construction period.Especially in the modern era of rapid economic development in our country,using high strength steel can in engineering structures can effectively save the corresponding construction cost,which is of great importance,and save the use of steel can be effective to reduce carbon emissions,so it can be confirmed that the use of high strength steel is a major trend of sustainable development of buildings.The main content of this paper is to study the bearing capacity of high strength steel compression member based on beam-column element method,in which the geometrical nonlinearity and material nonlinearity of beam-column element are discussed.In terms of geometric nonlinearity,the second-order effect is considered based on the stability function theory,and the stiffness matrix of spatial beam-column element is derived.In terms of material nonlinearity,this paper focuses on the yield surface of high strength steel.The yield surface can accurately reflect the ultimate strength of the component under the bending state.The yield surface of the section can be divided into the initial yield surface and the ultimate yield surface,which respectively represent the elastic strength and plastic strength of the section.The initial yield surface and ultimate yield surface with residual stress are calculated by using the fiber model method.The initial yield surface and ultimate yield surface with residual stress are calculated by using the fiber model method,and their numerical fitting is carried out.At the same time,the progressive yield effect caused by bending is analyzed,and the corresponding element stiffness matrix is derived.In order to verify the applicability of the beam-column method deduced in this paper,this paper uses MATLAB software to compile the calculation program of the bearing capacity of the beam-column element and the calculation program based on the yield surface of the fiber model.For the two types of components,Q460 and Q690 high-strength h-beam,the calculation results of beam-column element method are compared with the test results of existing scholars,and the comparison results show that the method has good accuracy and reliability.In order to further optimize the calculation program,this paper also discusses the rotation characteristics of beam-column elements and deduces the transformation matrix of element coordinates.Several common nonlinear methods and natural deformation method for unbalanced force calculation are summarized.Through the beam-column element method deduced in this paper and the comparison of test data,it can be seen that the calculation method of high strength steel bearing capacity proposed in this paper has a good applicability,it can well consider the impact of residual stress,and has a high calculation efficiency.Using this method in engineering design can eliminate the influence of the uncertain factors existing in the traditional design method,which has important practical significance.