Browsing by Subject "metrology"

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Access status: Open Access ,
Metoda pomiaru prędkości fal ultradźwiękowych w próbkach skalnych podczas testów laboratoryjnych
(Wydawnictwa AGH, 2008) Kanciruk, Adam
The measurement of the ultrasonic wave velocity in the process of uniaxial deformation of rocks specimens makes it possible to determine the degree of its internal destruction. For this purpose a standard testing device is equipped with a pair of special anvils. Each of them contains two piezoelectric ultrasonic transducers: one for P-wave, the other for S-wave. The tested cylindrical specimen is placed between the anvils after covering its faces with thin layer of couplant. The transducers of one anvil play the role of waves transmitters. They are attached to a typical industrial defectoscope output across a switch. Thus, electric pulses generated by the defectoscope can excite alternating both transducers. The transducers of the other anvil play the role of waves receivers. They are attached to two channels inputs of an analog-digital oscilloscope functioning in the digital mode. In this way the received signals can be easily observed on the oscilloscope display. In addition the oscilloscope synchronizing input is connected with the defectoscope output. It makes it possible to measure the period between the falling slope of the exciting pulse and the peak of the first positive pulse of the received signal. Thus, the P- or S-wave delay can be manually measured every 30 s with resolution of 20 ns. During the test another quantities like load, longitudinal and transverse strains are automatically measured and recorded. The obtained data can be used for elaborating rock material characteristics.
Access status: Open Access ,
Pomiary fali ultradźwiękowej w badaniach trójosiowego ściskania
(Wydawnictwa AGH, 2010) Dziedzic, Artur Robert; Łukaszewski, Paweł
The paper presents general description of novel system designed to measure of ultrasonic waves. Measuring module is implemented as an extending tool for Rock and Concrete Mechanics Testing System MTS 815. This equipment is capable to perform automatic measurements during triaxial tests and it automatically gathers data in real time. Measurements are carried out in the direction parallel to direction of axial stress. Ultrasonic transducers are connected directly to the MTS channels. This integration ensures full compatibility of ultrasonic data with other parameters measured by MTS system. For example, changes of ultrasonic velocities can be investigated with relation to entire path of deformation with respect to temperature and pressure conditions.
Access status: Open Access ,
Present metrological standards in mathematical modeling procedures
(2013) Twardowski, Kazimierz; Lewandowska-Śmierzchalska, Joanna; Przybyłowicz, Joanna
In the years 1993-1994 International Organization for Standardization (ISO) introduced to the metrology the fundamental changes of basic character, involving - in addition to the traditional concept of measurement error - the use of new fundamental term of uncertainty of measurement. In consequence, this has led to currently undisputed axiom of metrology, that the measurement result has a form of a section on dimensional axis. These rules of presenting measurable physical values should be reflected in the of practical procedures of mathematical modeling. Presented work relates to this particular problem. It discusses the principles of mathematical modeling together with the assessment of the results. Particular attention was paid to the identification of possible systematic errors (i.e. the load of model) and to estimating the uncertainty of the statistical and deterministic modeling.