The repeatability and reproducibility of calibrating signals generated by Hsu-Nielsen method

Abstract
During the measurements of the acoustic emission signals taken both in the laboratory and industrial conditions it is necessary to carry out calibration of the measurement paths used. One of the basic calibration methods is the one invented by Hsu-Nielsen, which consists in generating an acoustic signal during breaking a scriber placed in a special head put on an automatic pencil. The paper presents the measurement results of acoustic signals taken at various structural parameters of calibrating heads, which was done to determine their influence on the repeatability of the results obtained. Moreover, the measurements were taken for ten identical, in relation to their geometrical measurements, heads in order to test the repeatability of the results obtained using the methods of statistical inference. The paper characterizes the procedure methodology during formulating statistical hypotheses and describes tests of goodness of fit used for their verification. In Summing-up, based on the results obtained, the usefulness of the Hsu-Nielsen method in calibrating measurement paths used in the acoustic emission (AE) method of evaluating the hazard degree by partial discharges (PD) of insulation systems of power appliances was determined.