Effect of metal layer placement on the damage and energy absorption mechanisms in aluminium/glass fibre laminates

This study focuses on the effect of metal layer distribution in glass fibre reinforced aluminium laminates (GLARE) subjected to low velocity impact. Four GLARE variants specimens were considered in which the metal layers of different thicknesses were placed at various positions in the layup while keeping the same total metal layer thickness. Experiments and Finite element (FE) analysis were performed to understand the behaviour of the GLARE specimens. A user written material subroutine VUMAT which incorporates Hashin failure criteria along with Puck's action plane concept were used to predict the response of the composite layers. The damage was evolved for each failure mode using the exponential damage evolution law. Interface delamination between the layers was initiated by cohesive surface behaviour which includes the friction effect between the plies. It was found that placement of thinner metal layer on top of the laminate and its distribution inside the layup lowers the impact resistance of GLARE. Moreover, the patterns of delamination are also affected by the placement of metal layer within the laminates. It was further shown that the propagation direction of delamination is governed by the fibre direction of lower ply of the interface.