Flashcards
Force Transducers
Flashcards do conjunto (9)
- 1Load cellsElastic members may be used as force transducers, and, in this application, are commonly
referred to as “load cells” - 2What is the advantage of using an elastic member as a transducerThe advantage of using
an elastic member as a transducer is that we know that, as long as the yield stress is nowhere
exceeded in the member, the behavior of the member in response to an applied force or
displacement will be completely linear.
-Most frequently, the response of the elastic member is measured by measuring the strain
at a point on the member. Again, as long as we do not exceed the yield stress (and are operating
at a sufficiently low temperature so that creep effects do not become important), then the strain at
a point is a linear function of either the applied displacement or the applied load - 3How does a strain gague work?-As a rule, they function by changing
their electrical characteristics (resistance, capacitance) as a (hopefully linear) function of the
applied strain. By measuring the change in electrical characteristic, whatever it is, we obtain a
measure of the applied strain in the form of an electrical signal, which we can process. - 4Gage Factor (F)-the change in resistance experience by the gage is related to the strain by the gage factor
-The larger of the F, the larger the value of change of resistance or a given strain level - 5Foil gage-a thin, continous encapsulated strip of foil laid out in rows along the long axis of the gage
-As the foil stirp is stretched along the gage axis, its resistance changes linearly with strain - 6Semiconductor gage-similiar in principle to the foil gage, using a thin strip of silicon as the strain-senseing element
-Have gage factors of about 100
-Higher costs compared to foil gages and are brittle and difficult to apply to a curved surface - 7Simple force transducer-The ring has four strain gages
--The force required to elongate the ring will be a linear function of the measured strain values
-The four strain gages are wired as the four resistors of a Wheatstone bridge which is connected to a signal conditioning device
-The output voltage (which is proportional to the strain at the four gages) - 8Calibration of force transducers
- 9Procedure for determining the coefficient of friction
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- ME 021 FlashCards sobre Force Transducers , criado por Samina Forbath em 21-11-2018.
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- Samina Forbath
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