Abstract For damage detection of railway tracks, a two-axle test vehicle is better than a single-axle vehicle due to its capability of self standing and stability. This paper presents a new, comprehensive theoretical framework for a two-axle test vehicle moving over railway tracks modeled as a simply supported beam with elastic foundation. Firstly, closed-form solutions for both the vehicle and rail responses of the system were derived, along with those for the two contact points by a back calculation procedure. Secondly, the driving component of the contact-point response was processed by the Hilbert transform to yield the Instantaneous Amplitude Squared (IAS) for damage detection. Then, the efficacy of the proposed technique was numerically validated by the Finite Element Method (FEM). Particularly, the sensitivity of the proposed technique was investigated against various factors, including the damage severity, multi damages, vehicle speed, track unevenness, track damping, and measurement noise. The result shows that the IAS of the driving component of the contact point response of the railway track is a good damage indicator in that it is of low frequencies and narrow band, while its modal amplitude is sensitive to the stiffness loss in rail supports.

中文翻译：

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用于铁路轨道损坏检测的两轴试验车建模为具有弹性基础的简支梁

摘要 在铁路轨道损伤检测中，双轴试验车具有自立性和稳定性，优于单轴试验车。本文提出了一种新的、综合的理论框架，用于在铁路轨道上行驶的两轴试验车，建模为具有弹性基础的简支梁。首先，通过反向计算程序推导出系统车辆和轨道响应的封闭形式解，以及两个接触点的封闭形式解。其次，接触点响应的驱动分量由希尔伯特变换处理以产生用于损伤检测的瞬时幅度平方（IAS）。然后，所提出的技术的功效通过有限元方法（FEM）进行了数值验证。特别，针对各种因素研究了所提出技术的敏感性，包括损坏严重程度、多重损坏、车辆速度、轨道不平度、轨道阻尼和测量噪声。结果表明，铁路轨道接触点响应驱动分量的IAS频率低、频带窄，是一个很好的损伤指标，而其模态振幅对钢轨支架刚度损失敏感。