Explicit Buckling Analysis Of Rotationally Restrained Plates On Rigid Or Elastic Base Under Pressure And Shear Loading Conditions

In recent years,steel-concrete composite beam,as a new structure which combines steel and concrete to form double combination effect,has been vigorously developed in practical engineering application,and has realized the complementary advantages of concrete and steel.However,the middle bearing area of continuous composite beam is in the working state of large negative bending moment,so the steel beam is prone to local buckling under compressive stress,which affects its durability and reduces the bearing capacity.By pouring concrete in the belly of the steel beam to restrict one side of the web,the engineering practice shows that this can significantly improve the local bending capacity near the support.The stability of steel web restrained by concrete is still attributed to the problem of the stability of plate.From the point of view of theoretical analysis,this paper studies the elastic buckling behavior of elastic homogeneous rectangular thin plate on elastic rigid base under various boundary conditions and load conditions based on Kirchhoff hypothesis.Combined with the results of finite element analysis and web buckling test in negative moment region of a semi-filled steel box concrete composite beam,the accuracy of theoretical calculation is verified.The conclusion is obtained as follows:(1)In this paper,the appropriate functions of deflection are proposed.By using the Ritz energy method,the buckling problems of a rectangular plate with two-sided elastic rotational constraints on elastic or rigid base under uniform shear,linear compression and both compression and shear are theoretically derived,and the theoretical analytical solution of the critical buckling coefficient is obtained.The detailed parameter analysis is also carried out,which is consistent with the actual engineering situation,and has great practicability and applicability.(2)The ANSYS parametric design language APDL is used to compile the command flow program for modeling and eigenvalue buckling analysis.The finite element models of rectangular plates with different boundary conditions under shear and linear compression are established.The comparison between the finite element results and the theoretical results shows that they are in good agreement,and the trend of the finite element results curve and the theoretical curve is consistent,which proves the reliability and accuracy of the theoretical results in this paper.(3)By using the correlation stability checking formula,the buckling formula of plate on rigid base under bending shear stress is obtained.By comparing with the web buckling test results of a semi-filled steel box concrete composite beam in negative moment region,the result shows that the semi-filled concrete served as rigid base can be simplified as elastic base with stiffness coefficient slightly lower than 5.(4)For the buckling analysis of rectangular plates on elastic base with more complex elastic rotation constraint boundary under the combined action of uniform shear and linear pressure,the ANSYS finite element model is established,which has high universality.Many model control parameters are defined to facilitate model parametric design.It provides an idea for buckling analysis of more complicated thin plates with theoretical analysis limited.