Abstract In the present study, the behavior of circular plate made of fiber-metal laminates with curvilinear fiber subjected to low velocity impact is investigated using an analytical method. The plate response is eva‎luated for composite layers made of glass-epoxy that placed between two layers of Aluminum 2024-T3. Differential equations of motion are formulated using the spring-mass model and appropriate initial conditions for loading and unloading stages. In order to obtain analytical expressions for the load-indentation curve the deformation of aluminum were idealized as rigid-perfectly plastic and the composite layers as linear elastic. Using the principle of minimum total potential energy, applying the Von Karman strain and by neglecting the contribution of the in-plane displacements and bending strain energy, the nonlinear relationship between the contact force and deflection is derived. Also, a method for calculating the average stiffness of the plate with different layups is developed and employed to estimate the internal damage due to delamination. The equations are coded in MATLAB software and the impact load, velocity and kinetic energy of the impactor are calculated as a function of its position and time histories. The effect of layup and geometric parameters of the plate and the velocity and mass of the impactor on the plate response is investigated. Different functions are examined to describe the shape of the deformed plate under loading and the results are compared with the experimental data for validation purpose. Furthermore, an investigation of the possible performance improvements of a composite plate under impact loading through the use of the variable stiffness concept with curvilinear fiber is presented. The analytical results indicate a change in the stress distribution according to the curved fiber path within the variable stiffness laminates. However, the maximum deflection and the contact force of variable stiffness laminates are similar to the conventional, constant stiffness ones.

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