Buckling Failure Analysis And Parameter Optimization Design Of Flexible Thin-walled Cantilever Beam With Closed Section

In recent years,closed-section flexible thin-walled cantilever beams have been widely used in important engineering fields such as construction,aviation and shipping.In practical engineering applications,closed-section flexible thin-walled cantilever beams are often affected by the external environment and cause buckling failure of the structure,reducing the structural reliability,and may seriously cause a series of safety problems.In this paper,Rayleigh-Ritz energy method and finite element method are used to analyze the buckling failure of closed-section flexible thin-walled cantilever beams.The full-factor method,satisfaction function method and ANSYS technology are used to optimize the parameters of closed-section flexible thin-walled cantilever beams,improve the reliability of the structure to prevent structural buckling failure.Its main research work is as follows:(1)For the assumption that the closed section flexible thin-walled cantilever beam does not meet the constant shear flow in the middle plane,the previous simplified modeling method is no longer suitable for the buckling failure analysis of the closed section flexible thin-walled cantilever beam.A linear buckling analysis method based on Rayleigh-Ritz energy method.Firstly,the Rayleigh-Ritz method was used to fit the deflection function approaching the true infinite degree of freedom.Then the potential energy resident principle was introduced.The linear buckling critical load equation was derived.Finally,the linear buckling analysis of the closed-section flexible thin-walled cantilever was combined with ANSYS simulation technology.It is verified that the model is suitable for linear buckling analysis of the structure,and the analytical solution of the buckling failure load,the failure form of the structure,and the buckling mode are obtained.This will pave the way for the subsequent nonlinear buckling analysis of a closed section flexible thin-walled cantilever beam.(2)For the closed section flexible thin-walled cantilever beam under the influence of many factors in the actual operating conditions,its buckling towards the direction of nonlinear buckling and post-buckling development,how to simultaneously consider the track after the buckling path,points A nonlinear buckling analysis method based on the finite element method was proposed to solve the problems of the buckling of fork points and extreme points,the nonlinearity of structural materials and geometric nonlinearity,and the effect of initial defects on the buckling results of structures.Firstly,the improved arc length method is used to solve the non-convergence of the iterative process;then the “uniform defect mode method” and the classical bilinear follower enhanced constitutive model are used to add geometric defects and material nonlinearities to the structure;The finite element method considers the nonlinear buckling of flexible thin-walled cantilever beam with closed and cross-sections containing both defect and non-defect under both material and geometric nonlinear conditions,and effectively analyzes the failure of the structure in actual engineering.This will lay the foundation for the subsequent optimization of the parameters of closed-section flexible thin-walled cantilever beams.(3)For the closed section flexible thin-walled cantilever beam in the process of parameter optimization design is difficult to construct response optimization design model,conventional optimization algorithm is difficult to make global parameters optimal and response variable output error is large,making it difficult to improve the reliability of the structure,A new method of parameter optimization design based on full factor method,satisfaction function method and ANSYS technology is proposed.Firstly,the whole factor method was used to design the test.Then the ANSYS technology was used to solve the problem of large error in the output of the response variable in the previous analysis.The response optimization design model was constructed.Finally,the satisfaction function was transformed into the satisfaction function by the satisfaction function method.The simplification problem with the largest value obtained a solution that satisfies the optimization design under constraint conditions.By optimizing the parameters of the closed section flexible thin-walled cantilever beam,the optimal parameters are obtained,the reliability of the structure is improved,and a new idea is provided for the optimization design of the parameters of the structure,which has greater application value.