Dynamic Response of Sandwich Beam with Flexible Porous Core Under Moving Mass

The dynamic behavior of a sandwich beam with a porous core and carbon nanotube-reinforced polymer facesheets subjected to a moving mass on simple supports was investigated using the quasi-3D theory of shear deformation. The system of equations was determined using the energy technique. In order to solve the equations of motion, the analytical Navier’s approach in the space domain and the numerical Newmark’s method in the time domain were employed. Additionally, the natural frequencies of the free vibrations of beam were studied and evaluated. To validate the accuracy of the results obtained, comparisons were made with existing responses for specific circumstances reported in the literature. The effect of various parameters such as carbon nanotube volume percentage, porosity coefficient and distribution pattern, ratio of geometric and dimensional parameters, speed of moving mass, and facesheet-to-core thickness ratio on the dynamic response, critical speed of moving mass, and natural frequency of the sandwich beam with a porous core and nanocomposite surfaces were investigated. The results showed that by increasing the core porosity, the natural frequencies and critical speeds were increased. Because the intrinsic holes in the core structure get bigger, the stiffness and mass of the beam decrease. However, the effect of the mass reduction is greater than the effect of the stiffness reduction, so the frequency and critical speed of the system are increased.