Issue 41

A.S. Chernyatin et alii, Frattura ed Integrità Strutturale, 41 (2017) 293-298; DOI: 10.3221/IGF-ESIS.41.39 293 Focused on Crack Tip Fields The effect of residual stress on the nonsingular T-stresses A.S. Chernyatin, Yu.G. Matvienko, I.A. Razumovsky Mechanical Engineering Research Institute of the Russian Academy of Sciences, Moscow, Russia cas@inbox.ru , http://orcid.org/0000-0002-2708-8132 matvienko7@yahoo.com, http://orcid.org/0000-0003-2367-0966/ murza45@gmail.com A BSTRACT . The effect of residual stresses on surface fatigue crack propagation and fracture mechanics parameters of intersecting orthogonal cracks is discussed. Mutual influence of intersecting cracks and biaxiality affects the nonsingular parameters T xx and T zz . At the same time, the effect on the stress intensity factor is negligible. Two-parameter fracture mechanics is employed for an analysis of fatigue crack propagation taking into account residual stresses. The final configuration of the crack front is close to the semi-elliptical configuration. K EYWORDS . Residual Stress; Fatigue Surface Crack; T-stresses; Intersecting Cracks; Finite Element Simulation. Citation: Chernyatin, A.S., Matvienko, Yu.G., Razumovsky, I.A., The effect of residual stress on the nonsingular T-stresses, Frattura ed Integrità Strutturale, 41 (2017) 293-298. Received: 28.02.2017 Accepted: 03.05.2017 Published: 01.07.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION n analysis of propagation of surface cracks is considered in a number of publications [1-5], where the results of the experimental and numerical analysis of a flat semi-elliptical crack growth under cyclic loading are presented. The Paris formula or some subsequent modifications is used for calculations of fatigue crack increment. For assessment of the crack front configuration, the principle of self-similarity is used in most investigations. In this paper, the numerical method and the appropriate program realization are presented for the analysis of the surface crack growth in weld joint of a pipeline, including the calculation of changes in the crack front configuration due to action of the active cyclic loading, influence of no uniformly distributed residual stresses and the T-stress. It should be noted that the results of the mutual influence of intersecting perpendicular cracks on the parameters of fracture mechanics are not enough presented in the literature [6]. It is clear that the effect of the T-stress can be significant and the two-parameter fracture mechanics should be employed. The analysis of mutual influence intersecting cracks on the values and distribution of singular (the stress intensity factor) and nonsingular (the T-stress) components of the stress field along the crack fronts of intersecting cracks are also presented. A