Fracture Modes of Composite Plates under Impulsive Tensile Loads

The fracture mode of a bi-phase plane specimen under an external extensive im pulsive load was studied in this paper. The plane stress specimens were made from an orthogonal steel inclusion penetrated into an elastic matrix made of epoxy resin. The external pulse was applied at the free edge of the inclusion while the matrix remained motionless. The fracture mode of the epoxy-matrix consisted of a pair of cracks which started to propagate from the bottom corners of the inclusion and run perpendicularly to the overall direction of the impulsive load. The cracks formed in the plate follow a zig-zag path resulting in an overall sigmoid shape. This means that the stress conditions of the propagating crack-tips are not of uniaxial tension.