本文選題：結構健康監(jiān)測　切入點：振動測量　出處：《南京大學》2014年碩士論文　論文類型：學位論文

【摘要】：近年來,大型橋梁坍塌事故頻繁發(fā)生,導致巨大的生命、財產損失。橋梁在運營期間自身結構不可避免的出現損傷、老化的情況。在重型車輛長期作用下,內部應力可能嚴重受損,造成一定的交通隱患。隨著物聯網技術的發(fā)展,無線傳感器網絡技術越來越多的被應用到橋梁結構健康監(jiān)測中。如今越來越多的大型橋梁都配備了結構健康監(jiān)測系統。其中對大部分橋梁的結構健康監(jiān)測都包含了對其振動狀況的監(jiān)測,通過對橋梁結構振動信息的采集、分析來計算橋梁的振動模態(tài),測定橋梁結構的損傷、老化情況。 但是,橋梁結構本身存在著振幅小、固有頻率低的特點。而橋梁監(jiān)測現場往往環(huán)境惡劣,不僅要經歷天氣環(huán)境的變化,還要遭受復雜的電磁干擾�，F有基于振動信息采集的結構健康監(jiān)測系統往往在噪聲性能上存在不足,大量橋梁振動信息被淹沒在噪聲中,降低了數據準確性,影響了最終的模態(tài)分析。此外,由于大型橋梁跨度大,由通信距離過長而帶來一系列通信質量的問題,也降低了監(jiān)測結果的可靠性。 本文基于以往橋梁結構健康監(jiān)測的實踐經驗,提出并實現了一套應用于橋梁結構健康監(jiān)測領域的低噪聲振動采集系統。從傳感器選型、采集模塊設計、電路設計、電源模塊等多角度,融入了低噪聲的設計理念。使得新的振動采集系統在數據準確性方面相較于以往系統有著顯著提升。 本文提出的振動采集系統,由傳感采集模塊、控制處理模塊、通信模塊和電源模塊組成。其傳感采集模塊采用了更低噪聲、更高靈敏度的加速度傳感器,提高了數據采集的準確性。控制處理模塊利用了IRIS平臺強大的處理性能和可靠的環(huán)境適應性。通信模塊采用的Zigbee通信協議具備功耗低,靈活性強的優(yōu)勢,并通過通信距離擴展器的設計延長了無線通信距離,增強了數據通信的可靠性。電源模塊的設計兼顧了電壓穩(wěn)定和低噪聲,保障系統供能穩(wěn)定、潔凈。 低噪聲振動采集系統的軟件設計更多的考慮到橋梁結構監(jiān)測的實際應用,采用輪詢的方式進行傳輸控制。軟件設計中考慮到在執(zhí)行監(jiān)測任務時,諸多采集系統的時間同步。數據通信中采用確認重傳機制來進行差錯控制,提高數據通信的可靠性。 通過標準振動實驗驗證了系統對振動測量的準確性；與以往振動采集系統的對比,顯示了系統在低噪聲性能方面較以往系統有著顯著提升。在橋梁現場的振動采集實驗,采集到的數據真實有效,反應了系統能夠適應橋梁結構健康監(jiān)測的實際應用。
[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.
【學位授予單位】：南京大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U446

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相關期刊論文 前8條

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本文編號：1639961