Weld Fatigue Assessment of Rail Track Maintenance Machinery: Regulatory Compliance and Practical Insights
SAE-PP-00358
09/26/2023
- Content
- The use of appropriate loads and regulations is of great importance in weld fatigue assessment of rail on-track maintenance equipment and similar vehicles for optimized design. The regulations and available loads however are often generalized for several categories which proves to be overly conservative for some specific categories of machines. The work presented in this paper is about the strength and weld fatigue assessment of self-propelled rail on-track maintenance machines or similar equipment. It outlines the methodology and challenges associated with utilizing existing regulatory loads for weld fatigue assessment, specifically employing the endurance limit approach, also known as the infinite life approach. In cases where an endurance limit is undefined, particularly for welds, the fatigue strength limit at expected life cycles can be employed within the endurance limit approach. Availability of track-induced fatigue load data for the cumulative damage approach in track maintenance machines is often limited. Consequently, the Finite Element Analysis (FEA) based validation of rail TME often resorts to the infinite life approach rather than cumulative damage approach for track induced travel loads, resulting in overly conservative designs. This work compares the EN (European Norm) and AAR (Association of American Railroads) approaches in using specified loads in FEA-based weld fatigue assessment concerning track-induced vertical fatigue loads. It explains how the choice of available regulatory load affects the fatigue life predictions in self-propelled TME, highlighting the necessity for the regulatory loads that closely represent the endurance limit approach or loads suitable for the cumulative damage approach in the context of rail track maintenance machines. The EN and AAR regulations play a pivotal role in determining the applicable loads and acceptance criteria within this study. Additionally, the BS7608 regulation is used to determine weld class and predict weld fatigue damage. The study employs both nominal and Hot-Spot stress approaches to investigate and calculate fatigue damage.
- Citation
- Patil, D., and Petersen, M., "Weld Fatigue Assessment of Rail Track Maintenance Machinery: Regulatory Compliance and Practical Insights," SAE MobilityRxiv™ Preprint, submitted September 26, 2023, https://doi.org/10.47953/SAE-PP-00358.