低噪声振动采集系统实现及其在桥梁结构健康监测中的应用研究

发布时间：2018-03-20 16:45

本文选题：结构健康监测　切入点：振动测量　出处：《南京大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来,大型桥梁坍塌事故频繁发生,导致巨大的生命、财产损失。桥梁在运营期间自身结构不可避免的出现损伤、老化的情况。在重型车辆长期作用下,内部应力可能严重受损,造成一定的交通隐患。随着物联网技术的发展,无线传感器网络技术越来越多的被应用到桥梁结构健康监测中。如今越来越多的大型桥梁都配备了结构健康监测系统。其中对大部分桥梁的结构健康监测都包含了对其振动状况的监测,通过对桥梁结构振动信息的采集、分析来计算桥梁的振动模态,测定桥梁结构的损伤、老化情况。但是,桥梁结构本身存在着振幅小、固有频率低的特点。而桥梁监测现场往往环境恶劣,不仅要经历天气环境的变化,还要遭受复杂的电磁干扰。现有基于振动信息采集的结构健康监测系统往往在噪声性能上存在不足,大量桥梁振动信息被淹没在噪声中,降低了数据准确性,影响了最终的模态分析。此外,由于大型桥梁跨度大,由通信距离过长而带来一系列通信质量的问题,也降低了监测结果的可靠性。本文基于以往桥梁结构健康监测的实践经验,提出并实现了一套应用于桥梁结构健康监测领域的低噪声振动采集系统。从传感器选型、采集模块设计、电路设计、电源模块等多角度,融入了低噪声的设计理念。使得新的振动采集系统在数据准确性方面相较于以往系统有着显著提升。本文提出的振动采集系统,由传感采集模块、控制处理模块、通信模块和电源模块组成。其传感采集模块采用了更低噪声、更高灵敏度的加速度传感器,提高了数据采集的准确性。控制处理模块利用了IRIS平台强大的处理性能和可靠的环境适应性。通信模块采用的Zigbee通信协议具备功耗低,灵活性强的优势,并通过通信距离扩展器的设计延长了无线通信距离,增强了数据通信的可靠性。电源模块的设计兼顾了电压稳定和低噪声,保障系统供能稳定、洁净。低噪声振动采集系统的软件设计更多的考虑到桥梁结构监测的实际应用,采用轮询的方式进行传输控制。软件设计中考虑到在执行监测任务时,诸多采集系统的时间同步。数据通信中采用确认重传机制来进行差错控制,提高数据通信的可靠性。通过标准振动实验验证了系统对振动测量的准确性；与以往振动采集系统的对比,显示了系统在低噪声性能方面较以往系统有着显著提升。在桥梁现场的振动采集实验,采集到的数据真实有效,反应了系统能够适应桥梁结构健康监测的实际应用。
[Abstract]:In recent years, large bridge collapse accidents occur frequently, resulting in huge loss of life and property. Internal stress may be severely damaged, causing certain traffic hazards. With the development of Internet of things technology, Nowadays, more and more large bridges are equipped with structural health monitoring system. Monitoring their vibration, By collecting and analyzing the vibration information of the bridge structure, the vibration modes of the bridge are calculated, and the damage and aging of the bridge structure are measured. However, the bridge structure itself has the characteristics of small amplitude and low natural frequency. The existing structural health monitoring system based on vibration information collection often has some shortcomings in noise performance, and a large number of bridge vibration information is submerged in noise, which reduces the accuracy of data. In addition, a series of communication quality problems are brought about by the long communication distance due to the long span of large bridges, and the reliability of the monitoring results is also reduced. Based on the practical experience of bridge structure health monitoring in the past, a low noise vibration acquisition system is proposed and implemented in the field of bridge structure health monitoring, which includes sensor selection, acquisition module design, circuit design, etc. The design idea of low noise is incorporated into the power module and so on, which makes the new vibration acquisition system have a remarkable improvement in data accuracy compared with the previous system. The vibration acquisition system proposed in this paper consists of sensor acquisition module, control and processing module, communication module and power module. The sensor acquisition module adopts the acceleration sensor with lower noise and higher sensitivity. The accuracy of data acquisition is improved. The control processing module takes advantage of the powerful processing performance and reliable environment adaptability of the IRIS platform. The Zigbee communication protocol used in the communication module has the advantages of low power consumption and strong flexibility. Through the design of the communication distance extender, the wireless communication distance is extended and the reliability of the data communication is enhanced. The design of the power supply module takes into account the voltage stability and low noise, and ensures the stability and cleanliness of the power supply system. In the software design of low noise vibration acquisition system, the practical application of bridge structure monitoring is considered more and more, and transmission control is carried out by means of polling. Time synchronization of many acquisition systems. In data communication, confirmation retransmission mechanism is used to control errors and improve the reliability of data communication. The accuracy of the vibration measurement is verified by the standard vibration experiment, and compared with the previous vibration acquisition system, it is shown that the system has a remarkable improvement in low noise performance compared with the previous system. The collected data are true and effective, which reflects that the system can adapt to the practical application of bridge structure health monitoring.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U446

【参考文献】