Research On Method Of Damage Location Determination Using A Single Fiber Bragg Grating Sensor

In the fields of aerospace,electric power,machinery and other engineering,people pay more and more attention to various methods of structural health monitoring.In recent years,FBG sensors are widely used in the field of structural health monitoring because of their small size,light weight,insensitive to electromagnetic interference,easy to multiplexing and easy to be embedded in various structures to form intelligent structures.In this paper,a structural damage location determination algorithm based on single fiber Bragg grating vibration sensor is proposed.The algorithm realizes damage location identification based on the principle of non-destructive detection based on vibration response.The vibration response signal of the structure to be tested is acquired by a high speed FBG sensing demodulation system.The feature vector sensitive to the damage is extracted from the vibration response signal,and then the damage information is identified by the neural network.The specific work completed is as follows:1.A method of structural damage location determination based on a single FBG vibration sensor is proposed.The algorithm makes full use of FBG sensor to measure the sensitivity anisotropy during strain measurement.Extracting the feature vector containing the damage information from the vibration response signal by wavelet packet analysis.Finally,the damage location is identified by a neural network with strong nonlinear mapping capability.2.A FBG sensor demodulation system based on tunable F-P filter and unbalanced M-Z interferometer is designed.The system can not only measure the static or quasistatic temperature and strain accurately,but also monitor the high frequency vibration response signal.The experimental results show that the wavelength demodulation accuracy can reach ± 1.5pm when the temperature is measured,and the sampling frequency for the dynamic vibration response signal can reach 4 k Hz.3.The damage simulation experiment platform is built.Through the simulation experiment of damage location determination,the method of structural damage location determination based on single FBG vibration sensor proposed in this paper is verified.The experimental results show that this method can accurately identify the location of the damage in the plate structure,and the recognition accuracy is as high as 90.0%.