The assessment of energy absorption capability of aluminum/epoxy-glass fibers laminates after exposer to the thermal cycling

In the real conditions the composite structures set into the various environment conditions like thermal cycling. The aim of this work is to investigate the effect performing the thermal cycling on the absorbed energy capability of fibers metal laminates with aluminum skin and glass fibers/epoxy composites core with the various stacking sequence of glass fibers. For this reason, in the first step, the FMLs with two unidirectional configurations (0 /0 /0 /0 ، and 90 /90 /90 /90) and two bi-directional configurations (+45 /-45 /-45 /+45 and 0 /90 /90 /0) were fabricated. Then, the samples were aged by 0, 1, 10, 30, 50 and 90 thermal cycles. Each thermal cycle was heating the samples up to 100 C for 15 min, maintaining in this temperature for 5 min, and cooling them down to the ambient temperature for 15 min. After that, measuring the absorbed energy and characterizing the mechanisms were investigated by Charpy impact test, macrostructural method and microscopic analysis. The obtained results showed, up to 10 thermal cycles in the FMLs with unidirectional configurations, the absorbed energy capability has improved. After that, it had the reducing trend. The minimum and maximum sensitivity of absorbed energy capability in the thermal cycling were seen into the samples with the configurations of +45 /-45 /-45 /+45 and 0 /90 /90 /0 , respectively. The macrostructural investigation was showed, the delamination between fibers plies was the main failure mechanism in the FMLs, after performing 90 thermal cycles. By using the microscopic analysis was found that the thermal cycling caused to reduce the adhesion between glass fibers and epoxy matrix into the FML.