engleski

Influence of Multiple Preload on Results of Testing Machine Calibration

Preload plays an important role in the calibration procedure of a testing machine and represents an inevitable part of the calibration process. Preload affects the calibration results in the form of relative errors of the measuring system of force which is indirectly reflected also on the class of the measuring range. By performing one or several preloading there is a significant change in the values of characteristic relative errors: accuracy, repeatability and reversibility which represent the classification criteria in determining the class. A greater number of preloads makes worse the error of accuracy whereas the error of repeatability and in particular the error of reversibility are reduced in the absolute amount. Furthermore, preload affects also the residual force which remains on the standard measurement instrument after removing load. Already one preload minimizes this residue and thus allows valid testing. Therefore, the preload in checking the testing machine represents an important precondition of calibration with the aim of obtaining a right information about the accuracy of the tested measurement instrument.

preload; calibration; testing machine; force

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