HYBRID EXPERIMENTAL-NUMERICAL APPROACH FOR DETERMINING STRAIN-ENERGY RELEASE RATES

A new approach is presented for determining strain energy release rate s 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 cr ack closure parameters to calculate strain energy release rates. A tit anium specimen with a single edged crack under Mode I fracture has bee n used to demonstrate the approach. The stress intensity factor K(I) w as first calculated using the commonly used crack tip opening displace ment method. The strain energy release rate G(I) was then calculated u sing the hybrid experimental-numerical approach. The experimental valu es of K(I) and G(I) were compared with the published results to assess the accuracy of the experimental method. The experimental technique r eveals the importance of residual stresses.