Application of Response Surface Method in Probabilistic Fatigue Crack Propagation Life Assessment using 3D FEA

摘要

Fatigue crack growth life assessment is an important task in damage tolerant design practices. Being able to assess variability of crack propagation path and remaining useful life requires both deterministic and probabilistic modeling capabilities. Three-dimensional fatigue crack growth finite element modeling and Radial Basis Function based Response Surface modeling is shown to be an accurate and efficient route to predict crack propagation path in uncertainty quantification studies. A mixed-mode fatigue crack growth experimental measurement from literature is used for validation purposes and for quantifying crack path sensitivity due to off-nominal specimen geometry. Two sets of deterministic 3D crack propagation simulations are performed to relate geometric deviations to crack path predictions: first set is used to calibrate the response surface model while the second for verification purposes. Once verification requirements are satisfied, the response surface model can be employed in Monte Carlo type probabilistic simulations.