Low-Velocity Impact Analysis of a Viscoelastic Composite Plate with Flexible Layers Based on a Layerwise Theory and a Novel Energy Formulation

In the present paper, responses of a multilayer viscoelastic composite plate against a low-velocity impact by a rigid spherical indenter is investigated. In this regard, a novel energy formulation that is suitable for impact analysis and accounts for the potential energy due to indentation is proposed and employed, for the first time. First, Hertz contact law is refined to include effect of the lower layers on the stiffness of the contact region. Voltra hierarchical integral is employed for modeling the viscoelastic material and a layerwise theory capable of considering the transverse flexibility of the layers is used to accurately model the plate behavior. To solve the governing integro-differential equations, the finite element method, trapezoidal integration method, and Newmark numerical time integration method are used. In the results section, effects of the various viscoelasticity parameters and the indenter velocity on the time histories of the contact force, indentation, and lateral deflection of the plate are investigated. Results show that due to the damping nature of the viscoelastic materials, the plate rigidity and contact force increase whereas the maximum lateral deflection and the indentation decrease. Furthermore, higher contact forces do not necessarily indicates higher indentations.