Montalbán Domingo Laura, Zamorano Martín Clara, Palenzuela Avilés Cristina, Real Herráiz Julia I
Institute for Multidisciplinary Mathematics, Polytechnic University of Valencia, Camino de Vera s/n, 46022 Valencia, Spain.
Foundation for the Research and Engineering in Railways, 160 Serrano, 28002 Madrid, Spain.
ScientificWorldJournal. 2014;2014:363547. doi: 10.1155/2014/363547. Epub 2014 Oct 28.
The principal causes of cracking in prestressed concrete sleepers are the dynamic loads induced by track irregularities and imperfections in the wheel-rail contact and the in-phase and out-of-phase track resonances. The most affected points are the mid-span and rail-seat sections of the sleepers. Central and rail-seat crack detection require visual inspections, as legislation establishes, and involve sleepers' renewal even though European Normative considers that thicknesses up to 0.5 mm do not imply an inadequate behaviour of the sleepers. For a better understanding of the phenomenon, the finite element method constitutes a useful tool to assess the effects of cracking from the point of view of structural behaviour in railway track structures. This paper intends to study how the cracks at central or rail-seat section in prestressed concrete sleepers influence the track behaviour under static loading. The track model considers three different sleeper models: uncracked, cracked at central section, and cracked at rail-seat section. These models were calibrated and validated using the frequencies of vibration of the first three bending modes obtained from an experimental modal analysis. The results show the insignificant influence of the central cracks and the notable effects of the rail-seat cracks regarding deflections and stresses.
预应力混凝土轨枕开裂的主要原因是轨道不平顺和轮轨接触缺陷引起的动态载荷以及同相和异相轨道共振。受影响最严重的部位是轨枕的跨中部分和轨座部分。根据法规要求，轨枕中部和轨座的裂纹检测需要进行目视检查，并且即使欧洲规范认为厚度达0.5毫米并不意味着轨枕性能不足，这些部位出现裂纹仍需更换轨枕。为了更好地理解这一现象，有限元方法是从铁路轨道结构的结构行为角度评估裂纹影响的有用工具。本文旨在研究预应力混凝土轨枕中部或轨座部位的裂纹如何影响静态荷载作用下的轨道性能。轨道模型考虑了三种不同的轨枕模型：无裂纹、中部开裂和轨座开裂。这些模型通过从实验模态分析获得的前三阶弯曲模态振动频率进行了校准和验证。结果表明，中部裂纹影响不大，而轨座裂纹对挠度和应力有显著影响。
