Nonlinear Buckling Of Circular Arch Under Temperature Gradient And External Load

Steel arch structure is widely used in civil engineering,aerospace engineering,mechanical engineering and other fields because of its unique advantages.However,the thermal expansion coefficient of steel is large,which is greatly affected by the change of external temperature,so the steel arch structure is prone to buckling failure in high temperature environment.Therefore,it is of great practical significance to study the nonlinear buckling behavior of steel arch structure under external load and temperature gradient.In order to improve the research on the buckling of the arch under the temperature gradient,this paper takes the arc arch as the research object,the two ends fixed as the constraint conditions,uses the energy variation principle as the theoretical derivation method,and combines with the finite element simulation calculation,respectively studies the buckling behavior of the arch under the central concentrated load,the central concentrated load at any position,and the uniform load.It includes the following main contents:(1)Based on the principle of energy variation,the expressions of the nonlinear equilibrium equation and the axial bending moment of the circular arc arch structure under the combined action of the concentrated load on the arch crown,the concentrated load at any position,the uniform load and the temperature gradient are derived.The analytical solution of the buckling load of the arch under three conditions and the expression of the critical geometric parameters which distinguish the extreme point buckling and the bifurcation buckling mode are derived.(2)By setting different temperature gradients and geometric parameters,the variation laws of buckling load with temperature gradients and geometric parameters under the action of central concentrated load,concentrated load at any position and uniform load are obtained respectively,and the variation laws of radial displacement and bending moment with temperature under the action of uniform load and central concentrated load are also found respectively.(3)By setting different temperature gradients,geometric parameters and load positions,the buckling equilibrium paths of the arch under the central concentrated load,arbitrary concentrated load and uniform load are obtained by using the theoretical numerical calculation method.The effects of temperature gradients,geometric parameters and load position parameters on the buckling equilibrium paths are described respectively.