Photoelastic Study of the Interaction between a Plane Stress Wave and a Rigid Circular Inclusion

In the research programme described in this paper an experimental solution was obtained for the stress distribution around a rigid circular inclusion in a large plate during passage of a plane stress wave. The stress wave was generated by passing an air shock of fast rise and slow decay along an edge of the plate with a shock tube. The experimental methods used for the study were dynamic photoelasticity complemented with the moiré method of strain analysis. A transparent, low-modulus, birefringent, urethane rubber was used as the model material.

Transient free-field stresses were determined in the plate, at the inclusion location, before the inclusion was inserted. The magnitudes of these stresses at various times during passage of the stress wave were introduced into the static theoretical solution of Goodier to obtain what is referred to as equivalent ‘static’ stress distributions on the boundary of the inclusion. These distributions were then compared with the dynamic distributions obtained directly from photoelastic data at the corresponding times. The results of the study indicate that the static solution can be used to estimate the dynamic distributions if the free-field stresses are known. This finding is in agreement with previously reported analytical and experimental results for the case of an open hole.