Abstract
Two-dimensional fatigue crack growth from undercuts in longitudinal welds is investigated. The initial crack defects are assumed Poisson distributed with independent identically distributed initial shape parameters along a weld seam with identical material parameters. All the initial defects are exposed to the same stochastic loading.
The individual cracks are described as semi-elliptical surface cracks, and the Paris and Erdogan equation for fatigue crack growth is applied. An empirical equation for the stress intensity factor, given by Newman and Raju, for semi-elliptical surface cracks in a plate loaded in combined bending and tension, modified for the influence of interaction from other cracks, is used together with a magnification factor accounting for the additional stiffness due to the presence of the weld. The crack growth equation (two coupled first-order differential equations) are solved using an ordinary differential equation solver.
A weld seam with specified crack defect intensity is analysed, where the effect of crack coalescence is included. When cracks coalesce, a new crack configuration is defined, having a crack length equal to the sum of the coalesced cracks. A safety margin for exceedance of a critical crack depth is formulated.
The influence of the initial defect intensity on the estimated fatigue failure probability and on the joint density function for the crack geometry of the deepest crack at design life is investigated.
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© 1991 Computational Mechanics Publications
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Hansen, P.F., Cramer, E.H., Madsen, H.O. (1991). Stochastic Two-Dimensional Fatigue Crack Growth Analysis Including the Effect of Crack Coalescence. In: Spanos, P.D., Brebbia, C.A. (eds) Computational Stochastic Mechanics. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-3692-1_38
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DOI: https://doi.org/10.1007/978-94-011-3692-1_38
Publisher Name: Springer, Dordrecht
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