Hybrid experimental-numerical approach for determining strain energy release rates

Abstract

A new approach is presented for determining strain energy release rates using a hybrid experimental-numerical method. The deformation around a crack in a body under load is measured by moire interferometry and a finite element procedure is used to convert the displacement into crack closure parameters to calculate strain energy release rates. A titanium specimen with a single edged crack under Mode I fracture has been used to demonstrate the approach. The stress intensity factor K I was first calculated using the commonly used crack tip opening displacement method. The strain energy release rate G I was then calculated using the hybrid experimental-numerical approach. The experimental values of K I and G I were compared with the published results to assess the accuracy of the experimental method. The experimental technique reveals the importance of residual stresses.