Shear Post-Buckling Behavior of Glare Modeling Fiberglass Damage

The significant capability of Glare (Glass Reinforced Aluminum) to carry loads beyond the elastic range indicates that Glare panels could be proficiently exploited to work in post-buckling conditions. The paper aims at investigating by experiments and finite element analyses the shear post-buckling behavior of a Glare panel up to the failure load. Preliminary evaluation referred to the tensile response of Glare shows that an overestimation of the ultimate loads is obtained even when the plasticity of the light alloy layers is included. In fact, the multiple damage mechanisms occurring at high strain levels in fiberglass layers seem to play a not negligible role in the Glare response. Accordingly, a continuous damage law already proposed and validated, is herein used to model and investigate a shear buckling experiment using a Wagner's web with Glare panels beyond the critical load. The load vs. displacement curve, the budding shapes detected with Moire's fringes and the data acquired by means of strain gauges on the panel are reported. The panels exhibit an appreciable load carrying capability well beyond the onset of buckling. Numerical and experimental results appear comparable when both the metal plasticity and the damage of composite layers are considered. On the contrary, the adoption of a perfectly elastic response for the fiberglass plies leads to overestimate the capability of the structure undergoing Far beyond the first buckling load.