Plasticity induced crack closure is a leading mechanism to control main aspects of fatigue crack growth (e.g. stress ratio and load interaction effects) in metallic materials. The so-called Strip Yield model has proved to be the most versatile and powerful tool for estimating closure levels but its application to structural steels is not straightforward. This paper addresses the Strip Yield model applicability to a low strength structural steel. First, crack growth tests coupled with closure measurements by the compliance method have been carried out. It has been found that only the local compliance technique yields an adequate evaluation of closure, provided that the processing of the load-strain data accounts for compliance variations for the fully open crack. Subsequently, cyclic deformations near the crack tip have been simulated employing the Strip Yield model in conjunction with a novel method based on Westergaard’s complex potential. The analyses show that several conceptions of a constraint on yielding of the strip elements can be suitable in terms of the closure estimation but the local cyclic deformations are, in general, inadequately described.

Correlation between experiments and strip-Yield model results on fatigue crack growth in a structural steel

BERETTA, STEFANO;CARBONI, MICHELE;
2002-01-01

Abstract

Plasticity induced crack closure is a leading mechanism to control main aspects of fatigue crack growth (e.g. stress ratio and load interaction effects) in metallic materials. The so-called Strip Yield model has proved to be the most versatile and powerful tool for estimating closure levels but its application to structural steels is not straightforward. This paper addresses the Strip Yield model applicability to a low strength structural steel. First, crack growth tests coupled with closure measurements by the compliance method have been carried out. It has been found that only the local compliance technique yields an adequate evaluation of closure, provided that the processing of the load-strain data accounts for compliance variations for the fully open crack. Subsequently, cyclic deformations near the crack tip have been simulated employing the Strip Yield model in conjunction with a novel method based on Westergaard’s complex potential. The analyses show that several conceptions of a constraint on yielding of the strip elements can be suitable in terms of the closure estimation but the local cyclic deformations are, in general, inadequately described.
2002
Proceedings 14th European Confrenece on Fracture (ECF14)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/557507
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