Thermo-Mechanical Coupled Buckling Of Composite Sandwich Plate And Its Active Control

The sandwich plates are inevitably subjected to thermal and mechanical loads during use,so it is necessary to investigate the buckling behavior of sandwich plates under various loads.Many scholars have studied the thermal buckling of sandwich plates under different temperature distributions in the horizontal direction,and discussed the effects of different temperature distributions on the thermal buckling of sandwich plates.In order to increase the critical buckling load of the sandwich plate under thermal and mechanical loads,the piezoelectric actuator can be attached to the laminate plate to increase the critical buckling load using the stiffness provided by the voltage.Based on these analyses,the thermo-mechanical buckling behavior of sandwich plates is analyzed,and the active control of thermo-mechanical buckling of sandwich plates is studied.Based on the theory of enhanced shear deformation,the governing equations of sandwich plates are derived.The Rayleigh-Ritz method is used to solve the critical thermal buckling temperature and the critical buckling load of sandwich plates.Considering the uniform,linear and nonlinear changes of temperature along the thickness direction,the effects of temperature function index,boundary conditions,length-thickness ratio,aspect ratio,face thickness and total thickness and fiber angle on critical thermal buckling temperature and critical buckling load of sandwich plates were investigated.It is well known that the increase in temperature can reduce the critical buckling load of the sandwich plates.In order to keep the critical buckling load constant with the temperature rises,the fiber-reinforced piezoelectric actuator is bonded to the upper and lower surfaces of the laminate plate to realize the active control of thermo-mechanical buckling.Using the temperature feedback control method,the voltage across the piezoelectric actuator can be expressed as the product of the buckling control gain and temperature,so that the magnitude of the voltage can be controlled by adjusting the magnitude of the buckling control gain.Therefore,the equivalent stiffness generated by the inverse piezoelectric effect of the piezoelectric layer can be utilized to compensate for the equivalent stiffness of the sandwich plate due to the thermal effect,so that the occurrence of structural buckling can be controlled.When the critical buckling load of the sandwich plate remains unchanged as the temperature rises,the buckling control gain k at this time is called the critical buckling control gain.The effects of geometric parameters,fiber angle,paving patterns,boundary conditions,temperature sensitivity index and piezoelectric layer position on the critical buckling control gain are discussed.