Study On Algorithm Of Post-buckling Load And Deformation For Bar Structures With Large Deflection

Stability has always been the focus of engineering structure research.Slender bar structures having been widely used in engineering because of their own performance and characteristics,such as machinery,aerospace,shipping,automobile industry and other fields.In the theory of small deflection,the critical load is often used as the criterion of instability for bar structures.In the theory of large deflection,when the axial load is bigger than the critical load,some bars still have load carrying capacity and a stable post-buckling equilibrium stage.Therefore,there is of great practical significance to study the mechanical properties of post buckling for bar structures.In this paper,the influence of geometric nonlinearity is considered,the mechanical theory and the mathematical theory are combined,the objective function models of post buckling load for bar structures with fixed-free,simply supported at both ends and fixed-simply supported are established.The optimization methods and MATLAB programming language are combined,an optimization algorithm is proposed to calculate the buckling load and deformation of bar structures.The research objects are a cantilever beam with constant section,a simply supported beam with constant section and a statically indeterminate beam with constant section,the post buckling load and deformation are calculated by the optimization algorithm.The results of the optimization algorithm and references are compared,the correctness of the optimization algorithm is verified.For the examples of bar structures with constant section,the influence of section shape and boundary conditions on post-buckling load are studied,the relationship between load and maximum deflection and maximum horizontal displacement in post-buckling stage are discussed.The research objects are a cantilever beam with variable section,a simply supported beam with variable section and a statically indeterminate beam with variable section,the post buckling load and deformation are calculated by the optimization algorithm.The results of the optimization algorithm and ANSYS simulated are compared,it is verified that the optimization algorithm is also suitable for calculating the post buckling load and deformation of the bar structures with variable section.For the examples of bar structures with variable section,the influence of wedge rate on post-buckling behavior is studied.For bar structures,the post buckling load and deformation can be calculated fast and accurately by the optimization algorithm,which provides a reference for the study of post buckling behavior and has important theoretical and engineering significance.