Elastoplastic Analysis of Notch-Tip Fields in Strain Hardening Materials

Abstract : The elastic-plastic fields near a notch tip in strain hardening materials are investigated and modelled for a wide range of notch configuration, geometry, and load levels. Two engineering methods that are commonly employed for determining the elastic-plastic response at a notch tip are first assessed, and the results indicate that Neuber's rule and its various extensions tend to overestimate the plastic strain at the notch-tip, and underestimate the plastic strain away from the notch-tip. By contrast, the ESED method tends to underestimate the plastic strain at the notch-tip and its accuracy deteriorates as the load level increases. It is found that both methods are unable to provide satisfactory predictions of the stress-strain distribution ahead of a notch tip. To this end, an engineering approach is developed to characterize the stress strain distribution in the notch-tip plastic zone, taking into account of the in-plane and through-thickness constraints near the notch root. Predictions are compared with finite element results, showing a good correlation for all the cases investigated.

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