Effect of temperature and humidity on the mechanical properties of fibreglass/aluminium laminates

In the last decades, a new class of laminates, made of alternating layers of polymer matrix composites and metal alloys bonded together, has emerged as candidate for application in aeronautical structures. Among these new materials, often labelled as "fibre/metal laminates" (FMLs), GLARE, containing fibreglass laminae and aluminium alloy sheets, has been most widely studied, thanks to its relatively low cost and excellent fatigue and corrosion resistance [1,2]. Nevertheless, only few experimental data are available in the literature on the sensitivity of GLARE to temperature and humidity, which is a topical question to be answered in airplane construction. In this work, an FML similar to GLARE, fabricated at Alenia Aerospace, Pomigliano d'Arco using FM94 S-2 fibreglass prepreg tape and 2024-T3 aluminium alloy, was subjected to absorption tests under hot-wet conditions for times up to 7300 hrs and then mechanically tested. The mechanical characterization, carried out at temperatures ranging between 20°C and 90°C, consisted of Iosipescu in-plane shear tests and peeling tests. Similar tests were performed on virgin specimens. Some samples were also microscopically examined to assess their failure modes