Study On Calibration Experiments And Sensing Properties Of OPCM Sensors

The OPCM(Orthotropic Piezoelectric Composite Material) sensors,which can distinguish stress waves from the different directions and be used in the structure health monitoring system,are studied in this paper.Two kinds of OPCM sensors are explored,including 1-1 OPCM sensor and IDEs(Interdigitated Electrodes) 1-3 piezoelectric fiber OPCM sensor.These two kinds of sensors are mainly composed by piezoelectric phase and polymer in a sort of connective method.The piezoelectric phase can supply strong piezoelectric effect as active material.The polymer has low impedance and good flexility.They can conquer the disadvantage of brittleness and unconspicuous orthotropy for its changeable dimension,so they have a very widely application prospect in the field of the structure health monitoring system.Based on the piezoelectric-effect,the finite element simulation method is applied to analyze sensing properties by software ANSYS.The effect of the structural size on performance of IDEs 1-3 piezoelectric fiber sensor is explored.And we will optimize the design and manufacture of the two kinds of sensors by calibrating the 1-1 OPCM sensors and testing IDEs 1-3 piezoelectric fiber OPCM sensors.The main contents are summarized as follows:1.The piezoelectric theory and electromechanical relation about piezoelectric materials are presented in the microcosmic filed,while the excellent piezoelectric properties of PZT and the connection methods of the PZT pieces are analyzed.All of these can provide a powerful foundation for designing the sensors.2.The structural features and electric field characteristics of IDEs 1-3 piezoelectric fiber sensor are presented,and the constitutive relations are constructed. Based on the piezoelectric-effect,the finite element simulation is applied to analyze sensing properties by software ANSYS,At the same time the effects of the structural size of IDEs 1-3 piezoelectric fiber sensor is explored.3.The calibration platform and calibration system are designed,and the performance of 1-1 OPCM sensors are calibrated.The software MATLAB and the sensing properties of the Acoustic emission signal and the using breaking lead are analyzed in the FFT method.4.The Time-frequency analysis method is introduced,besides,the transform of FFT,wavelet packet-denosing,and gabor wavelet are listed.The importance of wavelet packet-denosing is indicated by analyzing the signals from PZT,SR-15A sensors and IDEs 1-3 piezoelectric fiber OPCM sensors;while,the IDEs 1-3 piezoelectric fiber OPCM sensors are proved more suitable for the structure health monitoring.