Vibration Buckling Of Composite Plates Caused By Stress Waves

Composite plates are widely used in all kinds of engineering and civil fields because of their excellent mechanical properties and excellent designable,and the study of their buckling has always been concerned by a large number of scholars.At present,the research on static buckling of composite plates has been sufficient,but the study of dynamic buckling is still full of challenges.In this paper,the buckling behavior of composite plates under step loading is studied.The main contents are as follows:(1)Based on the Kirchhoff thin plate theory and considering the stress wave effect,the vibration buckling of composite plates under step loading is analyzed.First of all,the vibration buckling control equation of composite plate considering stress wave effect is established by using Hamilton's principle,and the vibration mode function and initial geometric defect function which satisfy the boundary condition are substituted into the vibration buckling control equation of composite plate.According to the buckling condition,the expression of critical buckling load of composite plate under step load under different boundary conditions is derived.The effects of different boundary conditions,laying angle,layer thickness,layer number,modal order value,critical length,initial phase of mode function and initial geometric imperfections on the critical buckling load of composite plates subjected to step load are discussed.The analysis of the numerical example shows that the critical buckling load of the composite plate decreases with the increase of the critical length,the decrease of the laying thickness,the increase of the initial geometric defect coefficient and the decrease of the initial phase of the mode function.In addition,the smaller the angle between the laying angle of each layer and the direction of load is,the greater the critical buckling load is.When the number of symmetrical laying layers reaches seven layers,the critical load tends to be stable.(2)Based on Reddy's high-order shear theory and considering the stress wave effect,,the vibration buckling of moderately thick composite plates under step loading is analyzed.The vibration buckling control equation of the composite medium-thick plate considering the stress wave effect is established by using the Hamilton principle.The vibration mode function and the initial geometric defect function which satisfy the boundary conditions are substituted into the vibration buckling control equation of the composite plate,and the homogeneous linear differential equations including the critical load of vibration buckling of the composite plate are obtained.According to the conditions of buckling,the relationship between the critical length and the critical buckling load of medium-thick composite plates can be obtained by solving the equations.Through the analysis of a numerical example,the relationship between the critical load and the critical length of vibration buckling of medium-thick composite plates is discussed,and the results are compared with the results obtained by the classical thin plate theory.The results show that the relationship between critical buckling load and critical length of medium-thick composite plates under Reddy's high-order shear theory is similar to that obtained by thin plate theory,but under the condition of Reddy's high-order shear theory,the critical buckling load is smaller,and the effect of boundary conditions on the medium-thick composite plate is similar to that of the composite thin plate.