Design And Implementation Of CFRP Drilling Strain And Temperature Monitoring System Based On Optical Fiber

Carbon Fiber Reinforced Plastic(CFRP)is often joined to a metal material such as a titanium alloy or an aluminum alloy to form a laminated structure,which is then drilled and joined to other structural members.Due to the anisotropy and brittleness of CFRP,its pore-forming defects have been a problem that has plagued the efficient processing of such laminates.Real-time monitoring of the drilling process and optimization of the drilling process parameters facilitate high quality drilling quality.In this thesis,the CFRP drilling process is taken as the research object,and the drilling temperature and strain monitoring system based on fiber optic sensor is established,and the functional modules of related software systems are written.This paper covers the following main research contents:Firstly,review the research status of drilling strain and temperature measurement of carbon fiber laminates,analyze the functional characteristics of the monitoring system,establish the hardware of the monitoring system based on fiber optic sensors,and write the monitoring system software in C# language.Secondly,layout of fiber optic sensors for CFRP drilling strain temperature monitoring system.The parallel-arranged array and globally arranged spiral distributed optical fiber sensors are designed to analyze the characteristics of the two layout methods.The data processing methods of the two layout methods are studied,including time-frequency domain analysis and data reconstruction.Thirdly,build a CFRP drilling strain and temperature monitoring system based on fiber optic sensor,use Visual Studio2017 as a development test,and write software functional modules in C# language.Including: sensor production,monitoring data collection,monitoring data analysis,database storage and auxiliary functions five modules.Focus on the data transfer method between modules and the calling method of MATLAB function and LabVIEW dynamic link library.Connected to MySQL to establish an experimental database,categorize the drilling sample information and monitoring data to achieve efficient processing of fiber optic signals.Fourthly,based on the built monitoring system,the fiber grating sensor is used to carry out the drilling strain measurement experiment,and the communication debugging between the monitoring system and the commercial high-speed fiber grating demodulator is completed.The system data processing module is used to respectively array the array.The monitoring data of the distributed fiber with the logarithmic and logarithmic spirals is processed to verify the effectiveness of the monitoring system.