Experimental investigation of the influence of substrates’ fibers orientations on the impact response of composite double-lap joints

The main concern of this work is the mechanical characterization of the double-lap composite bonded assemblies under impact shear loads. The assemblies were made of unidirectional PEEK/Carbon composites and a brittle epoxy adhesive. The impact shear strength and failure strain were measured experimentally by the Split Hopkinson Pressure Bar apparatus, taking into account the set-up accuracy correction by finite element methods. The composite joints shear strength and strain at failure are sensitive to the loading rate and the substrates’ fibers orientation. The highest shear strength is recorded when the substrates fibers are oriented in the same direction as the impact loading. Moreover, the lowest shear strength is observed when the substrates fibers are oriented perpendicular to the impact loading. However, the loading rate and the substrates fibers orientation have opposite effects on the shear strain at failure.