Issue 41

F. Berto et alii, Frattura ed Integrità Strutturale, 41 (2017) 260-268; DOI: 10.3221/IGF-ESIS.41.35 260 Focused on Crack Tip Fields Review of the Influence of non-singular higher order terms on the stress field of thin welded lap joints and small inclined cracks in plates F. Berto Norwegian University of Science and Technology - NTNU, Department of Mechanical and Industrial Engineering, Trondheim, 7491, Norway filippo.berto@ntnu.no M.R. Ayatollahi Fatigue and Fracture Lab., Centre of Excellence in Experimental Solid Mechanic and Dynamics, School of Mechanical Engineering, Iran University of Science and Technology, Narmak, 16846, Tehran, Iran. S. Vantatori, A. Carpinteri Dept. of Civil-Environmental Engineering and Architecture, University of Parma, Parco Area delle Scienze 181/A 43124 Parma, Italy A BSTRACT . In stress analysis of cracked plates, alongside the stress intensity factor which quantifies the singular stress component perpendicular to the crack plane, the role played in crack growth by the constant term parallel to the crack plane, called the T-stress, has been widely investigated by many researchers. There are, however, cases of practical interest where the influence on the stress field of the higher order terms in the series expansion for the crack tip stress field, is not negligible. The main aim of the present investigation is to present and apply a set of equations able to describe more accurately the stress components for those cases where the mode I and mode II stress intensity factors used in combination with the T-stress are unable to characterise with sufficient precision the complete stress field ahead the crack tip. The starting point is represented by the Williams’ solution (Williams, 1957) where stresses as expressed in terms of a power series. An example is investigated of a thin-thickness welded lap joint characterized by various joint width to thickness ratios, in the range of d/t ranging from 0.5 to 5. The present paper indicates that the local stresses as well as the strain energy averaged over a control volume which embraces the slip tip, can be evaluated with satisfactory precision only by taking into account a further four terms besides K I , K II and T-stress. K EYWORDS . Crack; Stress intensity factors; T -stress; Higher order terms; strain energy. Citation: Berto, F., Ayatollahi, M.R., Vantadori, S., Carpinteri, A., Review of the Influence of non-singular higher order terms on the stress field of thin welded lap joints and small inclined cracks in plates, Frattura ed Integrità Strutturale, 41 (2017) 260-268. 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.