Bending and Buckling of Circular Sandwich Plates with a Hardened Core

Hard-core sandwich plates are widely used in the field of aviation, aerospace, transportation, and construction thanks to their superior mechanical properties such as sound absorption, heat insulation, shock absorption, and so on. As an important form, the circular sandwich is very common in the field of engineering. Thus, theoretical analysis and numerical simulation of bending and buckling for isotropic circular sandwich plates with a hard core (SP-HC) are conducted in this study. Firstly, the revised Reissner’s theory was used to derive the bending equations of isotropic circular SP-HC for the first time. Then, the analytic solutions to bending deformation for circular and annular sandwich SP-HCs under some loads and boundary conditions were obtained through the decoupled simplification. Secondly, an analytic solution to bending deformation for a simply supported annular SP-HC under uniformly distributed bending moment and shear force along the inner edge was given. Finally, the differential equations of buckling for circular SP-HCs in polar coordinates were derived to obtain the critical loads of overall instability of SP-HC under simply supported and fixed-end supported boundary conditions. Meanwhile, the numerical simulations using Nastran software were conducted to compare with the theoretical analyses using Reissner’s theory and the derived models in this study. The theoretical and numerical results showed that the present formula proposed in this study can be suitable to both SP-HC and SP-SC. The efforts can provide valuable information for safe and stable application of multi-functional composite material of SP-HC.

Vibration analysis of magnetorheological fluid circular sandwich plates with magnetostrictive facesheets exposed to monotonic magnetic field located on visco-Pasternak substrate

Magnetorheological fluids are materials that react to the applied magnetic field and are converted to the quasi-solid phase from the liquid one. Their applications in control and suppression of vibration have interested scientists nowadays. The present study is focused on the vibrational behavior of magnetorheological fluid circular plates that are embedded with magnetostrictive face layers. Magnetostrictive materials are also playing an important role in vibration control and are used widely in smart devices such as sensors and actuators. The structure is exposed to the transverse monotonic magnetic field and is located on the visco-Pasternak elastic substrate. Using Hamilton’s principle and based on classical plate theory, the motion equations and boundary conditions are extracted, and the generalized differential quadrature method is selected to solve them. Three different types of magnetorheological fluids are considered, and their effect on the results is discussed. The outcomes of this study can be used to design more capable and precise dampers, smart structures, and devices.