Fatigue Test Geometries Used for Girth Welds and Assessment of Residual Stress: State of the Art

Abstract Fatigue testing of girth welds in large tubes plays a crucial role in ensuring the structural integrity and safety of various structures such as oil and gas pipelines, raisers, monopiles, and wind turbines towers. The selection of appropriate test sample geometry and the influence of sample preparation is of utmost importance as it directly influences the accuracy and reliability of the fatigue test results. This review article highlights the significance of fatigue testing of girth welds and the importance of choosing the correct test sample geometry. Another critical aspect highlighted is the assessment of stress concentrations, along with the evaluation of the effects of residual stresses in fatigue testing of girth welds and welds done in close proximity. The choice of sample geometry should be representative of the actual structures being tested and should consider factors such as pipe diameter, wall thickness, weld bead profile, and potential stress concentrations. Improper selection of sample geometry can result in inaccurate fatigue life predictions and limit the practical application of test results. By conducting a literature survey on the geometry for fatigue test specimens of girth welds from large tubes, this study aims to provide insights into the significance of varying sample geometries when testing girth welds and their effects on residual stress and fatigue performance. The survey will include a comprehensive analysis of existing research, guidelines, methods, and standards related to fatigue testing of girth welds. The selection of correct test sample geometry and test method is a key factor in obtaining reliable and accurate fatigue test results. This article highlights the importance and challenges of fatigue testing of girth welds and emphasizes the significance of choosing the appropriate test sample geometry. This is conducted in form of a literature survey to further explore this crucial aspect of girth weld fatigue testing. A framework for future research and testing on girth welds, including welds performed at close proximity, and further assessment of residual stresses is also presented.