Research On The Judgment And Processing Technology Of Crack Signal Based On Smart Film

With the economic development and the social progress, more and more bridgeshave been built up. However, the safety accidents of bridges are also increasing.During the period of design, construction and operation, bridges are facing variousunsafe factors, which continue to threaten the security of our life and property.Therefore, structural health monitoring for bridges has become a frontier direction ofscience and technology.On the basis of research status of crack monitoring, bionic crack monitoringsystem based on smart film is firstly introduced. Then as the part of crack signaljudgment and processing, the existing problem and its solution of smart film cracksensor are analyzed. Finally, smart film crack sensor is applied to the bridges togetherwith other supporting facilities, aimed to provide an important reference for the safeoperation of the bridges and health assessment.The main contents of this paper are presented as follows:(1) The research background and significance of this paper are firstly analyzed,then the research status of bridge crack monitoring in and abroad, bionic crackmonitoring system based on smart film and the structural design of smart film areintroduced. According to the structure of smart film, the existing problem betweenmagnetic wires of its bus is pointed out, that is, coupling interference.(2) Through coupling interference analysis between magnetic wires of the bus, itcan be found that coupling interference exists during signal detection. And in a certainfrequency range, the voltage of coupling interference increases with the frequency ofdetecting signal. At the same time, whether interference exists is verified under thefrequency of1KHz. It can be seen from the experimental results that the voltage ofcoupling interference increases with the frequency of the input signal. When thevoltage goes beyond a certain value, it will affect the status judgment of magneticwires. However, when the frequency is1KHz, the measured voltage is35.2mV. Thevalue can be ignored because it will hardly affect the judgment.(3) Aimed to solve the interference problem, the secondary processor is improved.That is, low-frequency detecting signal and the custom judgment mechanism are usedto decrease interference. The effectiveness of the improved design is to be verified bythe experiments. And it can be found by the experimental results that the secondary processor can collect data accurately and in time, transmit data to the host computer(the upper computer), and update the display interface of status simulation of magneticwires and the stored data of the background.(4) The improved crack sensor is applied to the practical bridge. The MasangxiYangtze River Bridge and the installation crafts of smart film crack sensors are firstlyintroduced. Then the hardware and software design of crack monitoring system for itstowers are analyzed. Through the long-term monitoring of the bridge, the monitoringresults can be obtained, the effectiveness of smart film crack sensor can be verified,and the research in this paper is proved valuable.To sum up, this paper analyzes the interference problem between the parallelmagnetic wires of the bus and then solves it. The research can be verified valuable bythe results of the practical application to the Masangxi Yangtze River Bridge.