الفهرس 
chapter 1Only 14 pages are availabe for public view
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Abstract
The dynamic force transducers parameters (stiffness, damping coefficient, and
head mass) are important in determining the frequency range of each force
transducer used at the different dynamic setups. Since the force transducer
sensitivity is changed greatly after the resonance frequency. The aim of the
present study is to demonstrate two new measurement methods in measuring the
parameters of the dynamic force transducers under applying static force and
creep. These new approaches are distinguished by their stability and accuracy as they depend on using primary measurement devices precisely assembled; dead weight machine and laser interferometer device. An impulse dynamic force
calibration machine at the National Institute of Standards (NIS) in Egypt has been developed in this study to apply a complete calibration including measuring the parameters of force transducers beside their dynamic sensitivity. As the machine
becomes including air bearings as a guide for the falling mass and an
accelerometer for measuring its acceleration. Also, the distance between the force transducer and the falling mass has become more precisely adjusted using a
micrometer. The force transducer parameters measured under applying these
different measurement methods have been compared with each other and
compared to those parameters measured under applying sinusoidal dynamic force
for validation. The sinusoidal dynamic force measurement method has been
introduced there as a measurement service in Germany at the PhysikalischTechnische Bundesanstalt (PTB). Also, the two measurement methods of the
force transducers parameters under applying static force and creep have been carried out at PTB.
The dynamic sensitivity, for one of the force transducers under study, is
measured using the impulse method. Then it has been compared by its static
sensitivity. The analytical investigations showed that the new measurement techniques
(static and creep) for the force transducers parameters presented in this study are
promising. As their results are reliable, and accurate using simple mechanisms instead of complex dynamic systems. There is a sensible difference between the stiffness values of the force
transducers measured under applying the sinusoidal dynamic measurement
method and the other measurement methods in this study. This difference in case
of the 20 kN force transducer reached 22.88% and in case of the 5 kN force
transducer reached 19.65%. On the other hand, small and insignificant
differences of the stiffness are observed between the other three measurement
methods. These differences are about 0.07%, and 0.278% in case of the 20 kN,
and 5 kN force transducers respectively.
An obvious but not significant differences have been observed between the various methods of measurement for the damping coefficient results. By
comparison to the creep measurement method, this differences in damping
coefficient ranged from -31.4% to -1.62% for the two force transducers.
A small difference (3.2%) is observed between the sensitivity of the force
transducer measured under applying the impulse dynamic calibration method and
the static calibration method.
More and above to the static and the creep measurement methods, the impulse
dynamic calibration machine at NIS has been well developed and can be used in
the dynamic calibration. Rocking modes, and introducing the adapter which links
the electrodynamic shaker with the force transducer are factors that affect the
accuracy of the force transducer’s parameters values in the sinusoidal dynamic measurements.