Dynamic optical technique applied to define the zone of 3D and transient effects during dynamic crack propagations

Abstract
The aim of this paper is to define the evolution of the out-of-plane displacement fields during a crack propagation on a SEN sample made in a brittle material (PMMA). This problem consists of determining the zones of difference between the theoretical formulation and the experimental out-of-plane displacements. In the literature, this zone is named zone of 3D effects and transient effects. To obtain the information of dynamic displacements around the tip and during crack propagation, Michelson interferometer is used and the interferograms are recorded by an ultra high speed CCD camera. The PMMA plate is a SEN sample and the material behavior is brittle. Comparisons between experimental data and theoretical formulations allow us to size the gap zone. The evolutions are studied according to the applied loading and the crack speed.