Abstract
Stress concentration factors (SCFs) at weld toes and weld roots as required for the effective notch stress concept (see [1, 2]) are usually computed using finite element analysis (FEA) which requires a certain amount of effort for model generation, the solving process, and postprocessing. Regression functions of many FEAs within given parameter bounds provide the possibility of a fast prediction of SCFs. This paper provides new and accurate regression formulae for the estimation of notch stresses at idealized weld geometries on the basis of multiple linear-elastic FEAs for the transverse stiffener (non-load carrying T-joint) under tension and bending of the load carrying slab. Regression of sampled finite element results has been performed using (a) second-order polynomial regression with coupling terms (PRC) and (b) artificial neural networks (ANN). The presented formulae are compared with several existing estimations of stress concentration factors. The new methods appear to show a higher quality of prognosis as well as apply to significant larger ranges of the geometrical parameters of the weld joint. The formulae presented here for the transverse stiffener add another welded joint to a series of similar surrogate models presented from Munich University of Applied Sciences in earlier publications and made available for use by the web-based tool SCF-Predictor.
Highlights
The effective notch stress approach according to IIW recommendations [1] is based on the idealization of weld toes and weld roots using a fictitious radius ρ = 1 mm
There have been several investigations on the effective notch stress approach using these three distinct radii to design against fatigue of welded joints made of different materials such as magnesium alloys [4, 5]
Existing estimations of SCFs at the weld toe of transverse non-load carrying stiffeners have been compared to two new estimations using polynomial regression with coupling terms (PRC) and artificial neural networks (ANN)
Summary
A comparison of the effective notch stress approach using the three radii with the well-known structural and nominal stress approaches can be found in [6] Sizing recommendations of this radius are based on the thickness of the weld leg length and sheet thickness based on accuracy and computational efficiency, as can be seen in [2]. Depending on the selected size of the radius and group of material, FAT classes have been derived by backward calculations from experimentally obtained life data using this concept conforming modeling rule for the fictitious radius ρ This way, the theoretical notch factor Kt represents already the fatigue notch factor Kf. The notch stress concept as described in [1, 2] has been originally proposed by Seeger et al [7] which was motivated on early works of Radaj [8] and Neuber [9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
