Fracture Behavior of Prestressed Composites Subjected to Shock Loading: A DIC-Based Study

The dynamic fracture behavior of a prestressed orthogonally woven glass fiber-reinforced composite material was experimentally investigated. A shock tube apparatus was used in conjunction with a tensile pre-loading device to apply nominally Mode-I dynamic loading to pre-tensioned, single edge notched specimens. The specimen response was observed with a stereo high speed camera arrangement, and the full-field displacement and strain distributions near the crack tip were extracted using the 3D digital image correlation technique. Critical stress intensity factors for each specimen were determined from the displacement and strain fields using an over-deterministic approach. The magnitude of the pre-load applied to the specimens was shown to influence the crack tip velocity as well as the dynamic stress intensity factor up to the onset of crack propagation. The effect of fiber orientation on both crack tip velocity and dynamic stress intensity factor was also observed.