Scaling Effects in the Low Velocity Impact Response of Fiber-Metal Laminates

Abstract

Scaling effects in the low velocity impact response of a polypropylene-based fiber-metal laminate (FML) structure have been investigated. The FML was based on a 2024 aluminum alloy, a self-reinforced polypropylene composite and a polypropylene film acting as an interlayer adhesive. The study focuses on the assessing the possibility of using scale model tests for predicting the full scale low velocity impact response of FMLs based on [Al_n, 0°/90°_n]_s and [Al, 0°/90°]_ns configurations. These two systems were used to scale four different sample sizes (n = 1/4, 1/2, 3/4 and full scale). The impact load-displacement traces were normalized and found to collapse onto a single curve, suggesting that the laminates obey a scaling law. Attention also focused on characterizing the resulting damage in these multi-layered systems, where it was shown that the deformation modes and failure mechanisms were similar in all four scaled sizes. Other parameters such as the maximum impact force and the time to maximum load showed little sensitivity to scale size. This evidence suggests that data collected from tests on small FML plates can be used to predict the low velocity impact response of larger, more representative structures.