Three-dimensional analysis of fatigue crack propagation using X-Ray tomography, digital volume correlation and extended finite element simulations

Fatigue crack propagation is usually analyzed as a one-dimensional problem and the identification of Paris' type propagation law is often performed using standardized samples. The present paper is devoted to the analysis of three dimensional fatigue crack propagation using advanced experimental, imaging, measurement and numerical simulation techniques. Fatigue experiments are performed in situ in a tomograph. The images are analyzed using digital volume correlation to extract displacement fields and crack geometry. Stress intensity factors are evaluated along three-dimensional crack fronts and compared to numerical simulations using measured boundary conditions and detected crack shape. Last, using a single experiment, local da/dN vs. Delta K laws are estimated within a large range of Delta K values. (C) 2012 Published by Elsevier B.V. Selection and/or peer review under responsibility of H.D. Espinosa and F. Hild.