A hybrid experimental-numerical procedure was applied to creep crack growth studies to determine growth rates in IN100 at 732°C. The procedure uses high-precision displacement data together with a finite-clement model of the test specimen, which incorporates a realistic constitutive model of the material behavior. Primary and secondary creep as well as plasticity effects are accurately represented. The differences between experimentally measured displacements and those calculated from the analytical model were attributed to crack growth.

Numerical procedures were developed for tracking experimental displacement values and releasing nodes in the finite-clement model to account for crack growth. Numerical results for crack growth rates correlated well with measurements of crack extension from the fracture surfaces as well as with extrapolated values of growth rate from previous investigations.