An experimental investigation into the lightning strike response of Z-pinned composite laminates

Despite their outstanding mechanical performance and lightweight characteristics, carbon fibre reinforced polymer (CFRP) composites also have some limitations, notably: poor delamination resistance and vulnerability to lightning strikes. Z-pinning through-thickness reinforcement (TTR) technology addresses the first of these and this research represents the first investigation on the lightning strike damage response of Z-pinned CFRP composites. Two types of specimens were tested: unpinned and 0.1% carbon-fibre Z-pinned. Experimental results reveal that while Z-pinning enhances through-thickness electrical conductivity, it introduces new complexities. During lightning events, the intense current surge causes the carbon-fibre pins and adjacent resin pockets to decompose, resulting in localised damage, larger delamination areas, and reduced residual strength compared to unpinned laminates. Carbon-fibre Z-pinned laminates, however, dissipate heat more rapidly due to the efficient heat transfer facilitated by the pins. This study offers a novel perspective on the potential advantages and challenges associated with the application of Z-pinning in aircraft structures.