Elastic Lateral Buckling And Application Of Double Span Continuous Beams

The stability of the performance of steel structures is a particularly important factor to determine their bearing capacity, stability theory and design methods to be perfected. In recent decades since the steel to play in the study of the potential stability and improve the stability of the theoretical aspects of computing, both at home and abroad have made great progress. Steel structures such as perfect elastic-plastic stability theory, research has geometric defects and residual stress of the steel structure of the actual mechanical behavior and its ultimate load, using numerical methods to solve such problems has made a lot of research results. At the same time for theoretical analysis to test the stability of performance, as well as theoretical research results of the use of charts or deepen the express purpose of calculating the formula, thus the stability theory of elastic-plastic design of steel structures used in resolving the issue have achieved fruitful results.The main contents of this paper is to propose a new continuous beam stability theory, to improve and develop the existing theories, which is based on continuous model, using the energy variational method give some complex analytical solution of the problem, at the same time give the corresponding high accuracy of numerical solution. Compared with the finite element model, analytical methods of this paper are fast and effective, the data results are reliable, and establish the foundation formula for the utility project.The main work includes the analysis of cross-section's geometric parameters, especially the torsional stiffness parameter K for the post-lateral torsional buckling of steel beams to carry out parametric analysis to provide a basis for later analysis. Introduce finite element model of approach and for single-span simply supported beam give concentrated load and uniformly distributed load under the FEM solution and theoretical solution of the comparison, in order to provide a basis for follow-up study.Separately based on the integrity of the total potential energy expression and simplify the expression of total potential energy give the corresponding single-span simply supported beam lateral torsional buckling of some of the trigonometric functions to answer questions and high-precision numerical solution, and the introduction of dimensionless parameters to the principle of no loss of accuracy , using the concept of state-space implementation of the original quadratic eigenvalue problem into a state vector for the eigenvector of a generalized eigenvalue problem. And for uniformly distributed load under biaxial symmetry, such as cross-section dual-span continuous beam lateral torsional buckling problem give high-precision numerical solution, by calculating the return of a substantial and reliable formula for calculating the critical buckling moment. And select the eight kinds of Chinese-made H-shaped steel section, eight kinds of American Standard W-beam cross-section series, 12 kinds of self-designed cross-section set up the FEM model of continuous beam by finite element analysis to verify this article under uniformly distributed load, such as two-span continuous beam critical buckling bending moment calculation formula, and made a number of new problems.