铁路桥梁动挠度惯性测量方法

Inertial Measurement Method for Railway Bridge Dynamic Deflection

铁路桥梁动挠度测量一直是困扰工程界的难题。传统的相对式测量方法需要在测量现场找到静止不动的基准点，难以实现。用地震式传感器测量动挠度，传感器的有限低频效应导致输出信号的畸变。本文提出一种结合信号恢复处理，用地震式低频振动传感器测量桥梁动挠度的新方法。利用信号恢复技术，补偿因地震式低频振动传感器频率特性而畸变的输出信号。本文深入讨论系统存在零点时的恢复方法以及噪声下信号恢复处理的不适定性问题。利用桥梁动挠度的部分先验知识，外推信噪比差的部分低频谱线，反演原始信号。本文的研究为列车激励下桥梁空间振动形态的测量提供了便捷有效的手段。

Railway Bridge Dynamic Deflection (BDD)is an important parameter for bridge quality evaluation. BDD influences the security and stability of a train in motion. However, measurement of BDD remains an unresolved problem up to now. On one hand, it is difficult to find a stationary reference plane in testing site for a re lative measurement system. On the other hand, the BDD signal will be distorted when measured with a seismic transducer due to the limited low frequency response effect of seismic transducer. In this paper, the authors put forward a new method for measurement of BDD with seismic low frequency vibration transducer (called DP). Signal recovery technique is adopted to compensate DP's output which is distorted by DP's frequency response characteristics. And part known of knowledge of BDD is furtherly incorporated in reconstruction of some low frequency spectral lines which are contaminated seriously by low frequency noise. Then the real measured signal is acquired. The work in this paper provides a convenient and effective method for measurement of BDD, which lays the foundation for measurement and research of bridge spatial vibration excited by a train passing by.