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1986 | Buch

Vibration measurement

verfasst von: Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ

Verlag: Springer Netherlands

Buchreihe : Mechanics: Dynamical Systems

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Über dieses Buch

Nowadays, the engineering practice raises far more vibration problems than can be theoretically explained or modelled. Because Df this, measurements are used in almost all fields of industry, transportation and civil engineering in studies of mechanical and structural vibration. They are an invaluable tool for designing products and machines with high reliability and low noise level, vehicles and buildings with improved comfort and resistance to dynamic loads, as well as for obtaining increased safety of opera­ tion and optimum running parameters. In order to cope with the increasing demand for experimental measurement of vibration characteristics, young engineers and designers need an introductory book with emphasis on "what has to be measured" and "by what means" before learning "how measurements are done". The expertise to perform vibration measurements must be gained in time, with every new investi­ gation and studied problem . .A detailed presentation of instrumentation and measuring techniques is beyond the aim of this book. Such information can be found in product data sheets, application manuals and hand­ books supplied by equipment manufacturers. Only general princi­ ples and widely used methods are presented herein, in order to provide the reader with an overview of the instrumentation and techniques encountered in vibration measurement.

Inhaltsverzeichnis

Frontmatter
1. Introduction
Abstract
Speaking about mechanical vibrations, the following question arises: What is vibration ? The answer differs according to the extent of the notion.
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
2. Elements of the theory of vibrations
Abstract
Mechanical vibrations can be classified using various criteria.
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
3. Effects of vibrations
Abstract
Vibration measurement data are interpreted according to their nocivity. Beyond certain limits, vibrations are harmful to people, can produce damages in buildings or may disturb the normal operation of machinery. Studies in this field refer to persons, buildings and machinery. Persons are the most sensitive to vibrations. Safe limits and vibration severity criteria are presented in the following.
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
4. Transducers and pickups for vibration measurement
Abstract
The transducer is a device which converts changes of mechanical quantities into changes of other physical quantities, most commonly to an electrical signal proportional to a parameter of the experienced motion. Mounted in a more complicated device, the transducer becomes a pickup (velocity pickup, displacement pickup, etc.).
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
5. Instrumentation for vibration measurement
Abstract
Considering an instrumentation system (Fig. 5.1), having an input x i (t) and an output x 0(t), a system frequency response function can be established, having two parts — the amplitude spectrum (Fig. 5.2 a) and the phase spectrum (Fig. 5.2 b). These spectra describe how the input signal is altered when passing through the instrumentation system: the frequency components falling within the flat passband of the system remain unaltered, the others being attenuated and shifted in phase.
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
6. Vibration Exciters
Abstract
This chapter describes several types of vibrators (shakers) which are currently used either in reliability testing, fatigue testing and instrument calibration or for determining the dynamic characteristics of structures, machinery, foundations, etc. They may be parts of vibration testing machines or may be included in vibrating mechanisms for conveyers or process installations. Piezoelectric, magnetostrictive and pneumatic vibrators are not presented herein.
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
7. Instrument set-ups and techniques for vibration measurement
Abstract
Selection of the adequate components of an instrumentation system depends on several factors which must be weighted at the planning stage of any measurement program. The following are among the most significant: a) measurement location and direction, available space for transducer and equipment installation; b) frequency range and amplitude range; e) required accuracy for the data; d) environmental conditions (temperature, humidity, magnetic fields, radiation, noise); e) form of the final record which is desirable; f) number of identic or different physical quantities to be measured simultaneously; g) type of analysis: time domain or frequency domain; h) duration of test program; i) cost considerations; j) personnel skill and experience.
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
8. Calibration of transducers and instrumentation systems
Abstract
Calibration of instruments used for vibration measurements consists in determining the relationship of the output (electrical or mechanical) to the input (displacement, velocity, acceleration, force, torque). The ratio of these quantities is called calibration factor or, more often, sensitivity (especially for transducers).
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
9. Examples of vibration measurements
Abstract
A detailed treatment of the vibration measurement techniques, applied in various fields of engineering practice, is beyond the frame of this work. Therefore, in the following, only some of the most widely used modern measurement methods will be briefly presented, as well as some techniques used by the authors at the Strength of Materials Laboratory of the Polytechnic Institute of Bucharest, hence connected to their field of interest.
Gheorghe Buzdugan, Elena Mihăilescu, Mircea Radeṣ
Backmatter
Metadaten
Titel
Vibration measurement
verfasst von
Gheorghe Buzdugan
Elena Mihăilescu
Mircea Radeṣ
Copyright-Jahr
1986
Verlag
Springer Netherlands
Electronic ISBN
978-94-017-3645-9
Print ISBN
978-90-481-8287-9
DOI
https://doi.org/10.1007/978-94-017-3645-9