Research On Abnormal Distribution Of Dielectric Information Based On Array Capacitance Sensing

As a new non-destructive testing technology based on fringe electric field effect,the array electrode capacitance imaging technology has the advantages of penetrability,non-contact,and the ability to perform unidirectional testing under limited space conditions.The array electrode sensor based on the principle of capacitance sensing can have high sensitivity to the abnormal distribution of substances inside the measured object,so it has advantages in detecting complex targets.This paper focuses on the design and characteristics of the new array electrode sensor in response to the detection requirements of the abnormal distribution of the ceramic matrix composite material structure.Aiming at the problem that the coplanar array sensor is susceptible to external interference during the detection process of abnormal media distribution and the detection accuracy is limited,a joint working mode for the array electrode capacitance sensor is proposed.Firstly,a coplanar 12-electrode sensor model is established,and the penetration depth,sensitivity distribution and capacitance data of the sensor in the joint working mode and the single-electrode working mode are compared and analyzed.Finally,through simulation and experiment,the image reconstruction work of the bonding layer material of the ceramic matrix composite material is carried out,and it is verified that the joint work method can improve the detection accuracy and detection efficiency.In order to cope with more complex detection conditions and improve the sensor's ability to sense the changes in the dielectric constant distribution caused by the change of the medium in the detection area,this paper proposes a U-shaped sensor and its adapted rotational measurement combined imaging method.The structure model of the U-shaped sensor was created,and the expansion optimization method of the capacitance matrix and the sensitive field matrix was established.The graphical visualization of capacitance data and sensitive field data is used to intuitively reflect the sensor characteristics,and the sensor performance is quantitatively analyzed with the uniformity of sensitivity distribution and capacitance data sensitivity as indicators.The image reconstruction accuracy was evaluated based on the image reconstruction results of the abnormal distribution of the composite material structure,and it was verified that the new sensor and the new imaging method can improve the accuracy of the reconstruction.In order to reduce the amount of calculation of the system and improve the detection efficiency,a method for extracting the peak value of capacitance data of U-shaped sensor under combined imaging is proposed.By analyzing the capacitance data under the rotating combined imaging,the capacitance data and the sensitive field matrix data are extracted.Use different imaging algorithms to reconstruct images of abnormal media distribution areas to verify the universal applicability of the method.The results prove that this data processing method can improve the detection efficiency under the premise of ensuring the reconstruction quality.