Use of notches in the shafts loaded by torque for improvement in accuracy of strain gauge measurements

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Use of notches in the shafts loaded by torque for improvement in accuracy of strain gauge measurements

Popis výsledku v původním jazyce

One of the decisive factors for the sensitivity of the strain gauge instrumentation is the sensitivity of used strain gauges. For foil strain gauges, we talk about 1 μm / m [1]. This value is reached for steel components at a stress of about 2 MPa. It can be understood as a limiting one in terms of reliable detection. Since the ideal value of strain in the practical measurements for commonly used foil strain gauges should be about +/- 0.15 % for the wire versions and circa 0.1 % for the semiconductor versions, we talk about 20 - 25 MPa on the surface of measured steel component when the final error can theoretically decrease below 1 %. However, many engineering applications are out of this range and thus the uncertainty of the results is significantly growing. Especially in direct detection of torque on the gearboxes shafts in order to determine their mechanical efficiency, this is crucial. Generally, as well as in the case of the mentioned gearboxes, a certain possibility of solving the above mentioned problem is offered by constructional and technological notches in which the mechanical stress is locally concentrated. There are many various approaches available to estimate the rate of increase in local tension against nominal values on smooth surface of stable cross-sections, unfortunately without determining of the location of calculated extreme value. This is why we work with finite element method that eliminates mentioned drawbacks and allows us to reliably apply the direct strain gauge measurement in applications with extreme demands on accuracy of results as the mentioned efficiency of gearboxes is.

Název v anglickém jazyce

Use of notches in the shafts loaded by torque for improvement in accuracy of strain gauge measurements

Popis výsledku anglicky

One of the decisive factors for the sensitivity of the strain gauge instrumentation is the sensitivity of used strain gauges. For foil strain gauges, we talk about 1 μm / m [1]. This value is reached for steel components at a stress of about 2 MPa. It can be understood as a limiting one in terms of reliable detection. Since the ideal value of strain in the practical measurements for commonly used foil strain gauges should be about +/- 0.15 % for the wire versions and circa 0.1 % for the semiconductor versions, we talk about 20 - 25 MPa on the surface of measured steel component when the final error can theoretically decrease below 1 %. However, many engineering applications are out of this range and thus the uncertainty of the results is significantly growing. Especially in direct detection of torque on the gearboxes shafts in order to determine their mechanical efficiency, this is crucial. Generally, as well as in the case of the mentioned gearboxes, a certain possibility of solving the above mentioned problem is offered by constructional and technological notches in which the mechanical stress is locally concentrated. There are many various approaches available to estimate the rate of increase in local tension against nominal values on smooth surface of stable cross-sections, unfortunately without determining of the location of calculated extreme value. This is why we work with finite element method that eliminates mentioned drawbacks and allows us to reliably apply the direct strain gauge measurement in applications with extreme demands on accuracy of results as the mentioned efficiency of gearboxes is.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20301 - Mechanical engineering

Projekt

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Návaznosti

N - Vyzkumna aktivita podporovana z neverejnych zdroju

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

EAN 2018 56th conference on experimental stress analysis, Conference Proceedings

ISBN

978-80-270-4062-9

ISSN

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e-ISSN

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Počet stran výsledku

6

Strana od-do

239-244

Název nakladatele

Česká společnost pro mechaniku

Místo vydání

Praha

Místo konání akce

Harrachov

Datum konání akce

5. 6. 2018

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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