The article presents the results of the influence of geometrical features of defects in materials on the level of identification by the eddy current method. The study involved the inner ring of the tapered roller bearing. Four test defects, located at a constant distance from the inner surface, and a subsurface marker defect were performed in the treadmill of the tested ring. The test defects had a constant cross-sectional area in a perpendicular direction to the surface of the eddy current head. The geometrical features of each defect were the following: shape, the perimeter of the defect projected onto the surface of the ring, and the width and height of the defect projected on the face of the measuring head. The study involved an inner surface (subsurface defect detection) and external surface (the study of surface defects). It has been shown that the shape of the defect affects the level of detection using the eddy current method.
The article presents the process of determining the speed of an unmanned rescue vehicle.The conducted investigations involved a measurement system developed for testing dynamic lorries. The application of a test system for low-speed all-terrain vehicles was possible due to a wide measurement range of sensors. Speed was tested employing two following methods:an indirect method consisting of the measurement of the instantaneous rotational speed of the wheel;a direct method consisting of the measurement of speed against the ground, taken with an optical speed sensor.The authors also describe the sources of interferences characteristic of both methods that include:the wheelspin affecting the correctness of speed determination in the indirect measurement;the unevenness of the surface (ground) hindering the correct operation of the optical speed sensor.The paper also presents the characteristics of the rotational speed of the wheels obtained in road and off-road conditions. Based on the obtained signals, linear speed was determined. Additionally, the article discusses methods for eliminating measurement disturbances.
The article describes the influence the operating frequency of the transducer on the possibility to detect corrosion using the eddy current method. A bearing ring with two artificially made corrosion defects was used as a test object. The authors determined the characteristics of the defect’s signal value in the function of frequency. The results obtained were then compared to the peak-to-peak value of the signal for a model ring. The tests confirmed the possibility of automatic detection of corrosion on the surface of bearing rings using the eddy current method.
The article presents the influence of the distance between a measuring head and a tested object on the results of eddy current defectoscopy test. The tests were conducted on the two inner rings of a tapered roller bearing where the test defects were performed. A one-millimetre hole corresponded to the surface defect. Internal blind holes in the shape of a rectangle corresponded to a subsurface defect. The research was performed with the use of a SSEC III PC defectoscope connected to a mobile PC. The measuring device is part of the system for the automatic quality control of bearing rings. The test was conducted for a slit having following dimensions: 0.1, 0.2, 0.3, 0.4, and 0.5 mm. The obtained characteristics are the composition of the pulse caused by the detected defect and the sine wave caused by the axial runout of the tested bearing ring. The correlation between the slit size and the value of the signal of the defect and the sine wave caused by axial runout of the tested ring was observed. The concept of “a coefficient of defect detection” was introduced. The described coefficient is a quotient of the value of the defect signal and the peak-to-peak value of the sine wave caused by axial runout of the tested bearing ring. The increase in the dimensions of the slit from 0.1 to 0.5 mm causes a 35 - 50% decrease in the coefficient of defect detection, depending on the test defect. A handle was designed to ensure a constant pressure of measuring head on the tested surface was proposed.
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