Characterization of the Mechanical Behaviour of Carbon Fiber Composite Laminate under Low Velocity Impact

Abstract

The main purpose of the present investigation was to determine the damages generated by the low velocities with the help of the experimental method (Impact by a drop test) and the finite element method. The commercial transient finite element package LS-dyna used to model the effect of slug impactor and circular notch induced damage in composite material subjected to low velocity impact. The studied composite material was T800S/M21 made of carbon/epoxy. The effect of circular notch was examined. The composite material was subjected to stainless steel slug impactor in the transverse direction dropping the composite laminate at the center with three different velocities (2.85 m/s, 3.47 m/s and 4.17 m/s). The analysis was carried out using the model MAT59 for laminate and a rigid body model MAT20 for the slug impactor. The automatic_surface to_surface has been used to model the contact between the impactor and the laminate and the contact_automatic_surface_to_surface_tiebreak to simulate delamination between layers. A good agreement had been shown between the finite element results and the experimental values obtained from the drop tower test. The impact load, impact energy, displacements and the maximal were reported as function of the impact time. The delamination area and the layer impact energy were represented as function of layer orientations. By increasing the impact velocity, the displacement, the delamination area, the contact load and the impact energy increases respectively. The circular notch had an effect on the displacement values; this values increases in respect of the impact velocities. At the reverse, the contact load decreases respectively in function of the velocities.The main purpose of the present investigation was to determine the damages generated by the low velocities with the help of the experimental method (Impact by a drop test) and the finite element method. The commercial transient finite element package LS-dyna used to model the effect of slug impactor and circular notch induced damage in composite material subjected to low velocity impact. The studied composite material was T800S/M21 made of carbon/epoxy. The effect of circular notch was examined. The composite material was subjected to stainless steel slug impactor in the transverse direction dropping the composite laminate at the center with three different velocities (2.85 m/s, 3.47 m/s and 4.17 m/s). The analysis was carried out using the model MAT59 for laminate and a rigid body model MAT20 for the slug impactor. The automatic_surface to_surface has been used to model the contact between the impactor and the laminate and the contact_automatic_surface_to_surface_tiebreak to simulate delamination between layers. A good agreement had been shown between the finite element results and the experimental values obtained from the drop tower test. The impact load, impact energy, displacements and the maximal were reported as function of the impact time. The delamination area and the layer impact energy were represented as function of layer orientations. By increasing the impact velocity, the displacement, the delamination area, the contact load and the impact energy increases respectively. The circular notch had an effect on the displacement values; this values increases in respect of the impact velocities. At the reverse, the contact load decreases respectively in function of the velocities.