Design Of Distributed Structure Seismic Response Monitoring System

With the development and advancement of technology and the increasing demand for structural engineering in modern society,the important functions of different engineering structures in the modernization of society are becoming more and more prominent.In order to be able to monitor the damage caused to building structures by earthquakes and other extreme natural hazard events more accurately and efficiently,it is necessary to establish specialized structural seismic response monitoring systems.Although structural seismic response monitoring systems have been widely installed and applied on various building structures at home and abroad,it is still difficult to achieve large-scale promotion and application of the seismic response monitoring system due to factors such as its expensive overall system cost,complex composition,long system installation and construction period,and difficulty in expansion after completion.Therefore,this paper develops a distributed structural seismic response monitoring system that is low-cost,easy to install,easy to develop and easy to use.The system is based on the STM32 platform and uses a signal synchronization board and a data acquisition instrument for system formation.The system can be extended to access the collector nodes according to the monitoring needs of the building structure.The signal synchronization board and the data collector are connected by CAN bus for the transmission of acquisition and control commands from the host computer,and the system is connected to the host computer by PoE switch for data transmission and system power supply.The main features of the system are as follows:(1)a single data collector can access 6 channels of IEPE sensing signals,synchronous acquisition with 16-bit precision.(2)The system can be expanded through the CAN bus to access multiple data collectors,which can flexibly adjust the monitoring position according to the demand,making installation and expansion easy.(3)The collector can access the network cable to complete data transmission and system power supply,without adding extra power supply equipment.The main research work of this paper is as follows:1.Overall system solution and hardware design.Analyze the selection of acceleration sensors in the current structural seismic response monitoring system,and use it to propose the main system design scheme.The hardware design of the system is further completed based on STM32,which mainly includes the circuit design of digital control module,power supply module,communication module and signal conditioning module.2.Control and communication program design of the system upper and lower computer software.Based on the hardware design,the system control and communication program design is carried out,in which the lower computer program completes data acquisition,transmission and synchronization,and cooperates with the upper computer to complete the real-time display,storage and human-computer interaction of the acquired data.The system completes data acquisition,transmission and synchronization through the lower computer program design of signal synchronization node and data acquisition node.The upper computer software is developed by Lab VIEW to realize the functions of data packet parsing,data decoding,data clearing,sensitivity coefficient setting,data storage and UI interaction of the collected data.3.Distributed structural seismic response monitoring system module testing.The acceleration acquisition performance and synchronization performance of the distributed system were verified by the module test of the data collector,the synchronization test of the distributed system,and the shaker and unidirectional shaker tests.The data communication,data transmission,data acquisition,and acquisition synchronization command control of the data collector were tested in modules to ensure the perfection and stability of the collector functions.The synchronization accuracy test results show that the average value of synchronization error between collectors is 1.0μs;the shaker test results show that the relative error between individual collectors and HP data acquisition is between 0.385～0.890%,and the relative error in time domain with HP system is about 1.490%,which indicates that the accuracy and reliability of distributed monitoring system can reach the same level with HP data acquisition equipment.4.The distributed data acquisition system developed in this paper was applied to the shaking table test of the frame structure,and both the distributed monitoring system and the centralized monitoring system were used for acceleration data acquisition to obtain the acceleration response data of the structure under three different working conditions.The test results show that the RMSE of the acceleration time ranges from 0.032 to 0.361 for the two systems,showing good overall agreement,which also verifies the system performance of the distributed structural seismic response monitoring system developed in this paper.