A Non-Destructive Impedance Method to Measure Semi-Periodic Structures

Most current methods to evaluate the distribution, concentration, and homogeneity of periodic structures within fiber composites exhibit limited operational capability. In view of this problem, we propose an experimental technique which, compared to the approaches used to date, characterizes the electrical impedance Z in the band close to the resonance of the sensor–sample configuration. Using analytical equations, we can evaluate the monitored part of the composite and its density at various depths of the tested sample. The method employs test blocks of composites, utilizing the resonance of the measuring device and the measured sample set; the desired state occurs within the interval of between f=3 kHz and 400 kHz.