Numerical and experimental study of carbon / epoxy composite laminate response to low velocity impact

Nowadays, low-velocity impact resistance and damage tolerance have become very important in the design of composite structures, especially in the aerospace industry, and have led researchers to evaluate the low velocity impact response in the design of composites. In this research, a numerical model for low velocity impact (LVI) of carbon /epoxy composite laminate is proposed. This 3D damage model is based on continuum damage mechanics with subroutine development (UMAT) in Abaqus/Explicit. In this model, the interlaminar and intralaminar damage is considered and the nonlinear shear behavior is applied to consider the plasticity in the matrix. To evaluate the results obtained from the numerical model, impact testing was performed at three levels of impact energy (10 J, 15 J and 20 J). In addition, in order to verify the failure mechanisms and the amount of damage caused by the impact, delamination area was measured using radiology technique. By comparing the response of the impact behavior, a good correlation was obtained between the experimental test results and the simulation, which shows that the failure model used is well able to predict the behavior of the composite in this process.