Issue 46

W. Song et alii, Frattura ed Integrità Strutturale, 46 (2018) 94-101; DOI: 10.3221/IGF-ESIS.46.10 94 Developments in the fracture and fatigue assessment of materials and structures High cycle fatigue assessment of steel load-carrying cruciform welded joints: an overview of recent results Wei Song, Xuesong Liu State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China. swingways@hotmail.com, liuxuesong@hit.edu.cn A BSTRACT . In this paper, high cycle fatigue failure behavior of steel Load- carrying Cruciform Welded Joints (LCWJ) is assessed by means of local approaches. Different analytical solutions for weld toe and weld root are extended and applied to illustrate the effects of LCWJ geometry under cycle tension and bending based on Notch Stress Intensity Factors (NSIFs). The extended analytical solutions are validated by comparing finite element data from several simulations in terms of LCWJ models, resulting in a good agreement. A bulk of experimental data taken from tests and the literature is calculated by the proposed solutions as the forms of SED, NSIF and Peak Stress Method (PSM). The results show that the NSIF-based analytical solutions for steel LCWJ are effective for high cycle fatigue failure analyses. K EYWORDS . Analytical solutions; Strain energy density; Load-carrying cruciform joints; Tension and bending. Citation: Song, W., Liu, X., High cycle fatigue assessment of steel load-carrying cruciform welded joints: an overview of recent results, Frattura ed Integrità Strutturale, 46 (2018) 94- 101. Received: 24.04.2018 Accepted: 06.07.2018 Published: 01.10.2018 Copyright: © 2018 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 s one of the most typical connection types in shipbuilding or ocean engineering structures, the Load-carrying Cruciform Welded Joints (LCWJ) is widely used. Numerous advanced local approaches have been proposed to characterize the fatigue life of welded joints, such as notch stress [1], hot spot stress [2], equivalent structural stress method [3], NSIF method [4, 5], SED method [6-10], PSM [11, 12], fracture mechanics method [13], and other method [14]. Due to large numbers of complicated FE models are required to be created, it is cumbersome and time-consuming process for serving the needed results. To simplify this procedure of creating models, an analytical formulation based on NSIFs is extended to calculate the fatigue life indicator of local approaches considering different joints geometry and cyclic loading modes. The fatigue life of the weld toe failure in LCWJ tends to take longer than weld root failure due to the discrepancy of crack locations. Zong et. al [15] discussed the effects of initial crack size and crack mode fatigue performance in LCWJ by fracture mechanics approach. In addition, Singh et. al [16] investigated the high cycle fatigue life variation of AISI 304L steel LCWJ considering lack of penetration sizes. Effective Traction Stress (ETS) and Equivalent Effective Traction Stress (EETS), which were based on structural mechanics theory, were employed to illustrate the weld toe and weld root failures as fillet A