FEA Stress Determination for Weld Fatigue using Hot-Spot Stress Method: Benchmarking and Rail Application
SAE-PP-00394
05/05/2024
- Content
- Welded joints in rail steel structures are typically assessed for fatigue using two different stress range approaches: nominal stress range and hot-spot stress range when using SN methods. The nominal stress range is a traditionally simplified method that provides a conservative estimation but lacks accuracy in considering stress concentrations. On the other hand, the hot-spot stress range method is a more advanced and refined approach that offers a more precise evaluation of stress concentration, making it suitable for complex geometries. In 2015, the British standard BS7608-2015 on Guide to Fatigue Design and Assessment of Steel Products incorporated the hot-spot method for evaluating weld joints, especially when using numerical methods as Finite Element Analysis (FEA). The weld classes are now categorically defined for both nominal and hot-spot approaches in new introductions, whereas earlier, it was based on the nominal stress approach only. Choosing the appropriate stress range method depends on various factors, including the weld joint's geometry, stress orientations, loading conditions, the desired level of accuracy, and primarily the available SN curve data for predicting fatigue damage. The work presented in this paper explores the hot-spot stress range approach for determining stress ranges in weld fatigue assessment for Rail Track Maintenance Equipment. The identified welds were evaluated and compared for fatigue stress ranges using IIW and BS7608 guidelines for the hot-spot stress approach. The effect of various mesh types and finite element (FE) modeling on peak and structural stress was studied and presented. Subsequently, the hot-spot approach was applied to assess the weld fatigue in rail equipment, and the results were compared with those obtained using the nominal stress approach.
- Citation
- Patil, D., "FEA Stress Determination for Weld Fatigue using Hot-Spot Stress Method: Benchmarking and Rail Application," SAE MobilityRxiv™ Preprint, submitted May 5, 2024, https://doi.org/10.47953/SAE-PP-00394.