Design Of RFID Sensor Network And Application In Structural Health Monitoring

In recent years,with the improvement of scientific and technological level and the national strength enhanced,basic facilities construction and modernization of propulsion became an important direction,the modernization work greatly in pursuit of monitoring the life cycle of equipment.The monitoring of equipment is a severe challenge to traditional nondestructive testing,because of its heavy inspection equipment,data distortion in a complex environment,and to meet the requirements of accuracy.Combing with structural health monitoring technology will become an effective solution.The high cost of using active sensor and the environmental risks of solving the batteries in structural health monitoring put forward a new solution to become imperative measures.Radio frequency identification technology(RFID)tags is passive,and wireless communication and so on characteristics of the RFID system,make the RFID sensor technology become the potential research direction.This paper study the RFID tag array sensing technology in structural health monitoring and the application of nondestructive testing field.The stress distribution in all position of specimen can be monitored and can get higher robustness of monitoring programme by the RFID system.This paper mainly introduces the work from the following aspects:(1)This article first introduces the application of nondestructive testing and structure health monitoring,discuss the advantages and disadvantages of the traditional nondestructive testing technology,then discuss the advantages and disadvantages of active sensors in the structure of the monitoring,put forward the RFID sensor technology can be used as the combination of nondestructive testing technology and structure of health monitoring technology application to adapt to the complex working environment.In the end,the origin of RFID is introduced,the research status,the application fields and prospects.(2)The paper introduces the use of RFID sensing technology in the metal crack detection method,then introduces the experimental equipment and the method to set up the experimental system used in the work,including the use of FreeRTOS system,and puts forward a set of frequency sweep technology to get the power to active tags.In turn,increase the frequency of time-frequency analysis algorithm to extract the RSSI with the power to active tags in average frequency as a ratio as a characteristic value to establish relationship with the depth of the defect,and the conclusion.(3)The paper introduces the tag array sensing technology to evaluate the bending stress of composite materials.Firstly,the layout of the tag array is analyzed,and the appropriate design of the label array is selected.Then,the label information of the samples with different deflections is collected by the label array attached to the surface of the samples.The average of the active power of different tags in the tag array is extracted,and the bending stress distribution of different tags is analyzed.Finally,all the tags of the whole tag array are collected.The relationship between the mean value of the full frequency tag array and the deflection of the specimen is established.Finally,the linear regression model is used to establish the relationship model between the mean value of the active power and the deflection of the tag array.The model is solved by the least squares and gradient descent algorithm,and the convergence results are obtained.(4)A monitoring system based on RFID tag sensing is designed.The RFID bending sensor tag based on Farsens resistance sensor tag and Spectra Flex Sensor bending sensor is designed.The design of the software interface of the monitoring system is displayed in the form of refresh interface and the reading and preservation of special RFID bending sensor tag can be selected as save form(txt,csv)and can be read back in real time.The information obtained is then used to obtain the bending degree of the monitored specimens.The bending experiment of RFID bending sensor and RFID tag array is carried out at the same time.Through the sensor,the bending degree of the sample is expressed intuitively in the form of return resistance difference,and the experimental data are compared to obtain a more intuitive relationship between the bending degree and the tag array extraction characteristics.