Abstract
The study is aimed at assessing the size of the error that arises when processing the results of examining the geometric characteristics of the bearing structures of rolling stock units using an algorithm without using trigonometric functions. The object of the research is a method of simplified alignment of the deflection function of body frame beams to the horizontal plane. One of the biggest problem areas is the lack of understanding by some customers of the work of the possibility of using this algorithm due to the lack of information about the errors that arise in the simplified calculation. The study was carried out by comparing the results of processing the initial data by two methods, obtained during the work on the inspection of the state of the supporting structures of the unit of the shunting diesel locomotive TGM6. One method, the algorithm of which is the subject of this study, assumes that no complex calculations are used during data processing. The second method involves the use of an algorithm for aligning the deflection functions of the body frame beams of a rolling stock unit of railways in the horizontal plane, taking into account all trigonometry tools, which will exclude the accompanying calculation errors of the simplified method. After processing the initial data, two sets of results were obtained – with the desired calculation error and without. Comparison of these datasets yielded an error value for frame tilt of 5.7. For clarity, the size of the error was compared with the expanded uncertainty values of the main sources of uncertainty in the methodology for examining the bearing structures of rolling stock. On the basis of the analysis of two methods of leveling the inclination to the horizontal plane of the deformed rolling stock body frame, the expediency of such an approach has been proved. The results obtained make it possible to reasonably use the Simplified approach to processing the data obtained during the survey of the geometric characteristics of the rolling stock. If necessary, the developed mathematical model can be used to improve the accuracy of calculating the uncertainty of measurements of geometric characteristics, as well as for use in the study of modification of existing or development of new measurement techniques
Highlights
The implementation of the international standard ISO 17025 [1] in the activities of testing laboratories involves the implementation of the scope of work based on the calculation of the characteristics of the method, in particular the measurement uncertainty
The following methods are used: – analysis method when creating an algorithm for the complete calculation of the rotation of the deflection function of the locomotive body frame for alignment to the horizontal plane; – comparison method for determining the sources of unaccounted for errors in the simplified calculation method; – measurement method was applied during the inspection of the technical condition of the TGM6 shunting locomotive, the results of which were the initial data for the research
The author analyzed the technique of simplified ma thematical alignment in the space of models of deformed frames of bodies of rolling stock of railways
Summary
The implementation of the international standard ISO 17025 [1] in the activities of testing laboratories involves the implementation of the scope of work based on the calculation of the characteristics of the method, in particular the measurement uncertainty. In some cases, the laboratory needs to independently carry out a wide range of work in order to prove the correctness of the application of the method – that is, to validate the test method. Such a need arises if the measurement method is performed using equipment that is not foreseen by the standard, the method is used outside the specified scope, or a proprietary measurement method has been developed. The greatest challenge is the laboratory-developed method validation task In this case, as a rule, the amount of work required to study the properties of the method is the largest
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