Fatigue probability model for AWJ-cut steel including surface roughness and residual stress

• Published in: Journal of constructional steel research Vol. 179; p. 106537
• Main Authors: Hultgren, Gustav, Mansour, Rami, Barsoum, Zuheir, Olsson, Mårten
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2021
• Subjects: Abrasive waterjet cutting; High strength steel; Probabilistic fatigue model; Residual stress; Surface roughness; Probabilistic fatigue model; Surface roughness; Residual stress; High strength steel; Abrasive waterjet cutting
• ISSN: 0143-974X; 1873-5983; 1873-5983
• DOI: 10.1016/j.jcsr.2021.106537

An analytical model for the fatigue probability of abrasive waterjet cut high strength steel as a function of surface roughness, surface residual stress, tensile strength and number of cycles to failure is presented. Based on the model, which is valid in the finite and infinite-life high cycle fatigue regime, the influence of the aforementioned parameters on the fatigue strength at different probability levels is studied. For validation, fatigue tests are performed on abrasive waterjet-cut dog-bone specimens manufactured from high-strength steel with a yield strength of 700 MPa. Residual stresses are measured parallel to the loading direction at the inlet, middle and outlet of the cut surface. Surface roughnesses are measured with laser line triangulation as well as a traditional contact stylus method, showing good agreement between both measurement techniques. The proposed probabilistic model shows good agreement with the experimental results with less than 4% error in the predicted mean fatigue limit. Furthermore, the applicability of the presented analytical expression in a probabilistic design framework is demonstrated. An engineering example is introduced demonstrating the implementation of the model in a finite-element simulation, accounting for both multiaxial loading and the statistical size effect. [Display omitted] •Experimental investigation of the fatigue performance and surface properties of abrasive waterjet cut high strength steel.•Probability of failure model valid in both finite and infinite-life High Cycle Fatigue regime.•Model of the influence of surface roughness, residual stress and tensile strength on the fatigue failure probability.•Finite-element implementation of weakest-link probability assessment of engineering steel structures.•Novel fatigue design guidelines for abrasive waterjet cut steel structures.