Fatigue class combination model to quantify the influence of multiple weld imperfections on fatigue strength

Journal of Constructional Steel Research, vol. 222, pp. 108930

Abstract

Fabrication-related defects are inherent in every weld, playing a crucial role in steel structures exposed to fatigue. These defects significantly impact the fatigue strength of the welded joint. However, the existing connection between fatigue strength values and the quality level of welded joints has been insufficient. While EN 1090-2, EN 1993-1-9, in combination with EN ISO 5817 specify permissible sizes for weld imperfections for fatigue-stressed joints, the connection lacks a scientific foundation, and true limits remain unknown. To address this gap, a methodology has been developed to determine FAT classes based on the size of weld imperfections. Through fatigue tests on welded details with imperfections and subsequent numerical investigations utilizing local fatigue concepts, a quantitative relationship between fatigue strength and weld imperfection size has been established. This forms the basis for the development of the “Fatigue Class Combination Model” (FCCM), detailed in this paper. This model efficiently considers multiple imperfections in a probabilistic manner within the FAT Class. By implementing this method, the need for time-consuming rework of welds is mitigated in the future, enhancing the verification concept for sufficient safety against fatigue failure with improved cost and resource efficiency.

Authors 2

1. Helen Bartsch corresponding Aachen Institute of Steel Construction

   RWTH Aachen University

   Affiliation as printed

   Institute of Steel Construction, RWTH Aachen University, Germany

2. Markus Feldmann Aachen Institute of Steel Construction

   RWTH Aachen University

   Affiliation as printed

   Institute of Steel Construction, RWTH Aachen University, Germany