摘要
采用人工通电加速腐蚀的方法模拟混凝土梁内预应力钢筋的自然断裂过程从而获得真实的断丝声发射信号,应用高频声发射传感器和分布式光纤监测系统从水下采集预应力钢筋断裂时产生的声信号,分析信号的时频域特征和时域统计特征参数,结果表明:断丝信号的超声波段在水中传播时发生频散,应采用20 kHz以下的时域统计特征识别断丝信号;铠装光缆可以接收到在水中传播的断丝信号,其在时频图上表现为一条竖直的条带,并且能量主要集中分布于100~200 Hz。采用时域统计特征参数分析光纤监测信号时,需要设定较小的门槛值截取信号进行分析;对于光纤水声监测工况来说,峰值指标的信噪比较低,裕度和峭度指标更适合于用来识别断丝信号。该研究为开发预应力混凝土结构断丝水下声光纤监测系统奠定了基础。
Here,the method of artificial electrifying to accelerate corrosion was used to simulate natural fracture process of prestressed steel bars in concrete beam to obtain real acoustic emission signals of broken wires.High frequency acoustic emission sensors and distributed optical fiber monitoring system were used to collect acoustic signals generated by fracture of prestressed steel bars in underwater,and time-frequency domain characteristics and time-domain statistical feature parameters of signals were analyzed.The results showed that ultrasonic wave band of broken wire signal undergoes frequency dispersion when propagating in water,time domain statistical features below 20 kHz should be used to identify broken wire signals;armored optical cables can receive broken wire signals propagating in water,they appear as a vertical band on time-frequency map,and energy is mainly concentrated within the range of 100~200 Hz;when using time-domain statistical feature parameters to analyze optical fiber monitoring signals,it is necessary to set a smaller threshold value to intercept signals for analysis;for optical fiber underwater sound monitoring working conditions,signal-to-noise ratio of peak value index is lower,margin and kurtosis indexes are more suitable for identifying broken wire signals;the study lays a foundation for development of an underwater sound optical fiber monitoring system to detect broken wires in prestressed concrete structures.
作者
商峰
宋文杰
韩金生
杨波
付垚
徐龙海
SHANG Feng;SONG Wenjie;HAN Jinsheng;YANG Bo;FU Yao;XU Longhai(State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100038,China;School of Civil Engineering and Architecture,Shandong University of Science and Technology,Qingdao 266590,China;Physical Acoustics Corp.Beijing Office,Beijing 100029,China;Allian Stream Photonics Technology Co.,Ltd.,Wuxi 214000,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2024年第3期305-310,共6页
Journal of Vibration and Shock
基金
国家重点研发计划(2018YFC0406903)
国家自然科学基金(51578544)
中国水利水电科学研究院科研专项(SS0145B122017)。
关键词
断丝监测
声发射
分布式光纤
水声探测
broken wire monitoring
acoustic emission
distributed optical fiber
underwater sound detection
