Evaluation of the Higher Order Terms of the Wedge-Splitting Specimen Based on the SBFEM

The scaled boundary finite element method (abbr. SBFEM) is a semi-analytical method developed by Wolf and Song. The analytical advantage of the solution in the radial direction allows SBFEM converge to the Williams expansion. The coefficients of the Williams expansion, including the stress intensity factor, the T-stress, and higher order terms can be calculated directly without further processing. In the paper the coefficients of higher order terms of the crack tip asymptotic field of typical wedge splitting specimens with two different loading arrangements are evaluated using SBFEM. Numerical results show the method has high accuracy and effectiveness. The results have certain significance on determining crack stability of the wedge-splitting specimen.

Deterministic Prediction of Stress Corrosion Crack Growth Rates in High Temperature Water by Combination of Interface Oxidation Kinetics and Crack Tip Asymptotic Field

Proper disposition of the environmentally assisted crack growth rate in terms of key engineering parameters is crucial for safe and economic long term operation of light water reactors. Accurately predicting stress corrosion crack growth rate requires the quantification of crack tip mechanics, crack tip oxidation kinetics and their interactions. Crack tip strain rate has been categorized as a fundamental parameter for stress corrosion cracking of austenitic alloys in light water reactor environments. Continuum mechanics is applied to quantify crack tip strain rate based on the crack tip asymptotic field. A general oxidation kinetics formulation is proposed based on solid state mass transport theory. Stress corrosion crack growth rates of austenitic alloys in high temperature water environments are formulated as a function of various engineering parameters by combination of interface oxidation kinetics and the crack tip asymptotic field. Recent experimental results of stress corrosion crack growth rates in simulated boiling water reactor and pressurized water reactor environments are analyzed and reflected in the model development and application. The importance of surface integrity on plant safety is emphasized. The plant material aging management methodology is applied to the recent cracking issues in light water reactors.