基于压电智能骨料的混凝土结构损伤主动监测方法

发布时间：2018-06-07 09:38

本文选题：压电智能骨料 + 波动法　；参考：《大连理工大学》2013年硕士论文

【摘要】：建筑结构地震损伤将造成重大人员伤亡及财产损失,然而现有结构损伤过程监测手段存在价格昂贵、极端条件下存活率低等问题,都无法有效获得地震过程中的结构损伤变化过程。基于以上原因,本文提出了基于压电智能骨料(Smart Aggregate,简称“SA”)的混凝土结构损伤主动监测方法,主要从以下几个方面进行了研究： (1)首先,研究了石基SA的在混凝土介质中所发送和接收信号的重复性。将SA布设在了混凝土梁中,采用两个传感器相互发送与接收的模式研究了在相同传播介质中,不同SA之间的发送与接收信号的一致性,研究表明本文使用的石基SA具有良好的可重复性。 (2)其次,本文通过实验对比了石基SA与文献中常用的水泥基SA两种传感器的性能特性。通过在混凝土构件相同位置成对布置石基与水泥基SA,使它们的波动传播介质相同,再通过对比所接收到的信号证明了本文使用的石基SA主动监测可重复性更好,信噪比更高,更适合作为主动损伤监测的传感器。 (3)再次,提出了混凝土结构小数据量主动损伤监测方法。利用labview程序搭建了混凝土结构小数据量主动损伤监测系统。该系统主要由NI高频信号采集仪、NI信号发生器、功率放大器和SA传感器四个主要组成部分构成。该系统是通过对混凝土梁进行波动扫频分析,从而找出对结构损伤敏感且接收信号较大的频率,并以该频率作为主动发射的频率,在固定的时间间隔内,自动发送和采集毫秒级这一频率的声波。通过实时监测不同时刻波动信号的幅值变化情况,来实现对混凝土结构内部损伤情况的实时监测。以该种方式进行主动损伤监测可大大减少SA所需要接收的数据量,且可实现连续损伤过程的主动监测。 (4)通过构件损伤试验验证了本文提出的小数据量结构损伤监测方法的有效性。针对混凝土梁构件的锯口损伤及压弯柱构件的开裂损伤进行了构件试验研究,建立了接收信号幅值变化与损伤程度的关系,研究表明该小数据量监测方式的可行性与有效性。
[Abstract]:Earthquake damage of building structure will cause heavy casualties and property losses. However, the existing monitoring methods of structural damage process are expensive, and the survival rate is low under extreme conditions. Neither of them can effectively obtain the structural damage change process during earthquake. For the above reasons, this paper presents an active damage monitoring method for concrete structures based on piezoelectric smart aggregate (SA), which is mainly studied from the following aspects: Firstly, the repeatability of the signals transmitted and received in concrete medium by stone based SA is studied. The SA is arranged in the concrete beam and the transmission and reception modes of two sensors are used to study the consistency of the transmission and reception signals between different SA in the same transmission medium. The results show that the stone base SA used in this paper has good reproducibility. Secondly, the performance characteristics of stone based SA and cement based SA are compared experimentally. By arranging stone foundation and cement base SAs in pairs in the same position of concrete members, the wave propagation medium is the same, and the comparison of received signals proves that the stone base SA active monitoring is more reproducible and signal-to-noise ratio is higher. It is more suitable as a sensor for active damage monitoring. Thirdly, an active damage monitoring method for concrete structures with small amount of data is proposed. A small amount of active damage monitoring system for concrete structures is built by using labview program. The system is composed of NI signal generator, power amplifier and SA sensor. By analyzing the wave sweep frequency of concrete beam, the system finds out the frequency which is sensitive to structural damage and receives large signal, and takes this frequency as the frequency of active emission, within a fixed time interval. Automatic transmission and acquisition of millisecond sound waves at this frequency. The real-time monitoring of the internal damage of concrete structures is realized by monitoring the amplitude of the fluctuation signals at different times in real time. Active damage monitoring in this way can greatly reduce the amount of data received by SA and realize active monitoring of continuous damage process. 4) the effectiveness of the method proposed in this paper is verified by the structural damage test. In this paper, the experimental study on the sawing damage of concrete beam members and the cracking damage of the bending column members is carried out, and the relationship between the amplitude change of the received signal and the damage degree is established. The results show that the small data monitoring method is feasible and effective.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375;TU317

【引证文献】