The Application of Double Torsion Testing to Unidirectionally Reinforced Composite Materials

To characterize the intralaminar fracture behavior of a unidirectional carbon fiber/epoxy resin composite material, two distinct sets of experiments were performed. First, the tensile mechanical properties of the lamina were determined by testing specimens with different fiber orientation at varying rates of deformation. Then, the Double Torsion technique was applied to characterize the fracture resistance of the material. The strain energy release rate vs. crack speed curve so derived is in agreement with measurements conducted by using the Double Cantilever Beam and Compact Tension techniques. The results of the research indicate that Double Torsion is an attractive technique for studying the time-dependent fracture of composite materials.