Experimental techniques for fracture instability toughness determination of unidirectional fibre metal laminates.

The aim of this work is to propose procedures for the measurement of the fracture toughness of fibre metal laminates (FMLs) reinforced with unidirectional fibres of aramid or glass. Experimental techniques for fracture toughness evaluation by using Compact (C(T)) and Single-Edge Bend (SE(B)) specimens obeying ASTM standards are introduced. Procedures from the standard for thick metallic materials were modified in order to overcome problems, which can arise when testing FMLs - that is, specimen buckling, indentations and crack growth in planes other than the plane of the fatigue precrack or notch. The methodology proposed was experimentally tested leading to satisfactory results.