Low-velocity impact response of composite laminates with steel and elastomer protective layer

In the presented study the response of a carbon-glass composite/steel/(elastomer) multi-material structure to low-velocity impact was investigated experimentally. Two different steel layer thicknesses, 0.125 mm and 0.25 mm, as well as the addition of a rubber layer were assessed regarding their influence on internal and external damage, the absorbed energy, force evolution, and deformation.It was found that the doubling of the steel layer thickness stiffens the structure marginally and induces deeper indentations but has no significant influence on the absorbed energy or the damage threshold FDFD. The additional rubber layer increases the damage threshold load. Below this threshold, the response is dominated by global, elastic deformation decreasing internal and external damage and thereby the amount of absorbed energy. Above FDFD, large local deformations around the centre of impact lead to a more critical surface damage which dissipate a part of the energy decreasing the extend of delaminations.