Title: A J-integral-based approach to predict the fatigue strength of components weakened by sharp V-shaped notches

Authors: P. Lazzarin, R. Zambardi, P. Livieri

Addresses: Department of Management and Engineering, University of Padova, Stradella S. Nicola 3, 36100 Vicenza, Italy. Department of Management and Engineering, University of Padova, Stradella S. Nicola 3, 36100 Vicenza, Italy. Department of Engineering, University of Ferrara, Via Saragat 1, 44100 Ferrara, Italy

Abstract: In the present paper, Rice|s J-integral is applied to sharp V-shaped notches subjected to mixed mode loading. The material is thought of as obeying a linear elastic or a power hardening law. J, which is no longer an invariant, as it was in the crack-case, is analytically given as a function of the relevant Mode I-II Notch Stress Intensity Factors (N-SIFs). As soon as a convenient choice of the integration path is made, J is demonstrated to be able to summarise the fatigue properties of steel and aluminium welded joints of different geometry. By imposing the coincidence between elastic and plastic J-integral values, both the degree of singularity and the plastic N-SIF value are evaluated on the basis of the relevant linear elastic values. When N-SIF|s are unknown, a general method suitable for determining J is reported. Finally, a new operator, JL, has been defined for sharp V-shaped notches. It is an invariant in the ambit of validity of the asymptotic stress distributions and in the presence of Mode I loading. In the linear elastic case, JL coincides with Rice|s J-integral when the notch opening angle is null (i.e. when the notch becomes a crack).

Keywords: fatigue; welded joint; V-notch; J-integral; notch stress intensity factor; elasticity; plasticity.

DOI: 10.1504/IJCAT.2002.000296

International Journal of Computer Applications in Technology, 2002 Vol.15 No.4/5, pp.202-210

Published online: 15 Jul 2003 *

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