Polymer–Metal Laminates for Fire-Resistant Lightweight Structures: Behaviour, Mechanism, and Design

Lightweight structural materials in aerospace are often vulnerable to degradation when exposed to thermal loads; this can lead to catastrophic loss of structural integrity. Existing passive fire protection methods add weight or fail to maintain strength under simultaneous thermal and mechanical loads. This study investigates and expands on the previous understanding of polymer–metal laminates (PMLs) for the enhancement of fire structural survivability for lightweight load-bearing structures. Novel PML designs, featuring stainless steel 304, aluminium and copper foil combinations, were manufactured onto aluminium substrates and later subjected to a combined thermo-mechanical load. The results demonstrated that integrating stainless steel 304 front layers into 10-ply laminate configurations enhanced the substrate’s fire structural survivability. Compared to front-facing aluminium laminate layers, the stainless steel 304 front layers improved the substrate’s thermal flux exposure time under a tensile force by 122%. Even after accounting for the increased weight, it was determined that two front-facing stainless steel 304 layers provided a normalised performance gain of 64%. These findings demonstrate the potential for fire structural survivability enhancements within aerospace environments using multi-metAl–PML configurations.