Gomes Vítor M G, Lesiuk Grzegorz, Correia José A F O, de Jesus Abílio M P
FEUP, Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, 4200-465 Porto, Portugal.
Wroclaw University of Science and Technology, Wybrzeże Stanisława Wyspiańskiego 27, 50-370 Wrocław, Poland.
Materials (Basel). 2024 Apr 16;17(8):1831. doi: 10.3390/ma17081831.
Leaf springs are critical components for the railway vehicle safety in which they are installed. Although these components are produced in high-strength alloyed steel and designed to operate under cyclic loading conditions in the high-cyclic fatigue region, their failure is still possible, which can lead to economic and human catastrophes. The aim of this document was to precisely characterise the mechanical crack growth behaviour of the chromium-vanadium alloyed steel representative of leaf springs under cyclic conditions, that is, the crack propagation in mode I. The common fatigue crack growth prediction models (Paris and Walker) considering the effect of stress ratio and parameters such as propagation threshold, critical stress intensity factor and crack closure ratio were also determined using statistical methods, which resulted in good approximations with respect to the experimental results. Lastly, the fracture surfaces under the different test conditions were analysed using SEM, with no significant differences to declare. As a result of this research work, it is expected that the developed properties and fatigue crack growth prediction models can assist design and maintenance engineers in understanding fatigue behaviour in the initiation and propagation phase of cracks in leaf springs for railway freight wagons.
板簧是其安装所在铁路车辆安全的关键部件。尽管这些部件由高强度合金钢制成，并设计为在高周疲劳区域的循环载荷条件下运行，但它们仍有可能失效，这可能导致经济和人员灾难。本文的目的是精确表征板簧所代表的铬钒合金钢在循环条件下的机械裂纹扩展行为，即I型裂纹扩展。还使用统计方法确定了考虑应力比影响以及诸如扩展阈值、临界应力强度因子和裂纹闭合比等参数的常见疲劳裂纹扩展预测模型（Paris模型和Walker模型），其结果与实验结果具有良好的近似性。最后，使用扫描电子显微镜（SEM）分析了不同测试条件下的断口，未发现显著差异。作为这项研究工作的成果，预计所开发的性能和疲劳裂纹扩展预测模型能够帮助设计和维护工程师理解铁路货车板簧裂纹萌生和扩展阶段的疲劳行为。
