Tests and numerical simulation on low velocity impact performance of fiber metal laminates

In order to investigate the low velocity impact performance of fiber metal laminates (FML) using the finite element numerical simulation method, a modified continuum damage mechanics (CDM) model was established and the numerical simulation of low velocity drop weight impact test on FML was conducted, the numerical simulation results were compared with the experimental results. The drop weight tests were performed with impact energies of 5.11 J and 10.33 J, respectively. The impact load, displacement and energy history for each test were obtained, thus the dynamic response and the damage pattern of FML were studied. Based on a continuum damage mechanics (CDM) model, the plastic deformation and compression stiffness attenuation of S2-glass/epoxy composite were supplemented as well as fiber tensile failure property, thus a new CDM model was established. The new CDM model was used to describe the constitutive and damage model of the S2-glass/epoxy composite in the FML, and was coded in user material subroutine (VUMAT). The numerical simulation of FML under drop weight impact test was then conducted through ABAQUS/Explicit solver. The results show that the main damage patterns on the rear surface of FML are bulging and cracking when impacted by low energy, and the peak displacement increases with increasing impact energy, while peak impact load increases with increasing impact energy before perforation. The dynamic response of FML is predicted well using finite element analysis when the S2-glass/epoxy composite layers are described by the modified CDM model. It is also found that the fiber tensile failure of the second composite layer is more serious than the first layer's through the finite element numerical simulation results.