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Fatigue Crack Propagation under Complex Loading in Arbitrary 2D Geometries Pages: 26 Published: Jan 2002
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View License Agreement Source: STP1411-EB Abstract A reliable and cost effective two-phase methodology is proposed and implemented in two pieces of software to predict fatigue crack propagation in generic two-dimensional structural components under complex loading. First, the fatigue crack path and its stress intensity factor are calculated in a specialized finite-element software, using small crack increments. At each crack propagation step, the mesh is automatically redefined based on a self-adaptive strategy that takes into account the estimation of the previous step stress analysis numerical errors. Numerical methods are used to calculate the crack propagation path, based on the computation of the crack incremental direction, and the stress-intensity factors , from the finite element response. An application example presents a comparison between numerical simulation results and those measured in physical experiments. Then, an analytical expression is adjusted to the calculated values, where is the length along the crack path. This expression is used as an input to a powerful general purpose fatigue design software based in the local approach, developed to predict both initiation and propagation fatigue lives under complex loading by all classical design methods, including the , the and the (for welded structures) to deal with crack initiation, and the to treat propagation problems. In particular, its crack propagation module accepts any expression and any rule, using a or a cycle-by-cycle propagation method to deal with one and two-dimensional crack propagation under complex loading. If requested, this latter method may include overload-induced crack retardation effects.
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