Rail Neutral Temperature In-Situ Evaluation
| 项目名称： | Rail Neutral Temperature In-Situ Evaluation |
| 摘要： | Continuous welded rails (CWR) are rails that are welded together to become long continuous members that are fixed at both ends. When the ambient temperature significantly increases or decreases from the rail neutral temperature (RNT), the temperature at which the rails experience zero stress, the metal can expand and cause the rails to buckle, or contract and cause the rails to fracture. These effects can, in a worst-case scenario, result in train derailment. However, even installing CWR at a median ambient temperature does not guarantee that a rail will not buckle or fracture in the future, and it is sometimes necessary to reinstall the entire rail. A means of preventing these faults is to measure RNT and longitudinal rail stress of CWR to determine if the reinstallation of the entire rail is warranted to increase safety. Several methods for measuring RNT and longitudinal stress exist, but they each have various pitfalls. RNT is traditionally determined by cutting the rail, measuring the gap, performing calculations, and rewelding the rail; but this method is destructive and labor intensive. Nondestructive methods exist; but they can be costly, are not always accurate, and may require contact with the rail. The technique being created is a nondestructive and noncontact method of measuring RNT and longitudinal stress. This technique uses a pulse laser to generate Rayleigh waves, which can be used to determine the longitudinal stress on the rails, and the RNT can be calculated using the relationship between the longitudinal stress, ambient temperature, and material properties. Rayleigh wave polarization is more sensitive and more robust than Rayleigh wave speed; thus it results in more accurate and more precise measurements. |
| 状态： | Active |
| 资金： | $159,564 |
| 资助组织： | Texas A&M University, College Station<==>Research and Innovative Technology Administration |
| 执行机构： | Texas A&M University, College Station |
| 开始时间： | 20140101 |
| 预计完成日期： | 20161231 |
| 主题领域： | Maintenance and Preservation；Railroads |
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