technique for measuring internal friction in vibrating reeds by Wm. R. Jewell Download PDF EPUB FB2
A technique for measuring internal friction in vibrating reedsAuthor: William R. Jewell. Download PDF: Sorry, we are unable to provide the full text but you may find it at the following location(s): (external link).
adshelp[at] The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86AAuthor: William R. Jewell. If dE is the loss of energy per cycle, and E the total energy, then 1/Q = dE/(2πE), Thus the internal friction is small when 1/Q is small.
Only in the last few years has the technique of measuring internal friction reached a point where the losses in single crystals can be studied [4, 16, 17].
The mechanism of internal dissipation of energy in. The Zener theory of internal friction in vibrating reeds has been generalized to three dimensions and expressions derived for the case where the grained structure of the reed is smaller than the wavelength of the standing wave. The theory is applied to the experimental values of the internal friction in vitreous silica; it is shown that such internal friction in silica may be explained by the Author: Mordechai Warshavsky, Howard A.
Robinson. Keywords: Amplitude dependent internal friction, ADIF, Ke's pendulum, Vibration reed. *e-mail: [email protected] 1. Introduction The internal friction technique or mechanical spectroscopy is very sensitive to the microstructure evolution and various defects in.
CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Abstract.- The vibrating-reed technique has been successfully adapted to internal friction studies of thin-layer materials. Three examples are described, related to the oxygen contamination of niobium films, grain-boundary sliding of aluminum films, and anelasticity due to hydrogen in metallic glasses.
The Young’s modulus and internal friction of these films were measured by vibrating reed method and evaluated with above formula.
The Young’s modulus of these films decreases continuously with temperature, while the internal friction increases monotonically. This paper describes in detail a freely vibrating reed apparatus which we have developed to study these low temperature dynamic mechanical properties of polymers (at approximately 5 cps).
The apparatus is capable of measuring these properties from 4 up to K. This method has the advantage over other methods of being relatively easy to set up and may be modified so more than.
An instrument for measuring the internal friction of rod shaped specimens in the kilocycle frequency range is described. The specimens are excited into longitudinal resonance electrostatically and a frequency modulation technique is used to detect the resultant vibration.
The linearity of the system is established by an absolute optical calibration technique and the accuracy of measurement. Two different techniques i.e. inverted torsion pendulum working at frequency of about 1 Hz and vibrating reed apparatus (clamped-free geometry) working at frequency c.a.
Hz were used. In both cases sample deformation does not exceed 5 × 10 −5. The idea of the paper consists in measuring internal friction spectra in the course of chemical reaction occurring in the examined.
decrement has been used frequently as a measurement of internal friction and can be measured using resonant bar techniques, the torsion pendulum, or high frequency driven oscillation, to name just a few. Here the resonant bar technique (similar to ) is used and is outlined in detail in a subsequent section.
This paper describes apparatus for measuring internal friction of nonferromagnetic reeds set in transverse vibration. It includes a description of a symmetrical transducer for inducing the vibrations and an optical method of observing the amplitude.
Measurements can be made while the reed is temperature controlled and vibrating in a vacuum. The design and fabrication of a fully automated, computer controlled, precise measurement system for sound velocity and internal friction using the vibrating reed technique is described in detail.
Relative variation of sound velocity and internal friction has been measured using automatic frequency locking. Abstract Mechanical spectroscopy (measurement of internal friction and modulus of elasticity) by the vibrating-reed technique on Fe–31 at.% Al polycrystals has been performed in the temperature range of – K after various thermal (quenching, annealing) and.
The actual solute content was assessed by thermoelectric power and X-ray diffraction. Internal friction was measured in a vibrating reed apparatus and in a torsion pendulum.
The internal friction level around room temperature shows a surprising linear correlation with the carbon content even in the absence of the Snoek peak. This internal friction level is attributed to long-range interaction of edge.
Curing process of an amine-epoxy system was investigated using vibrating reed technique and torsion pendulum apparatus, working at frequencies of about Hz and 1 Hz, respectively. The measurements of mechanical spectra were carried out in isothermal conditions (– K) at different frequencies in time domain i.e.
in the course of. acoustic measurements we have used the vibrating reed technique. The samples had a length of (3- 7)mm, mm width and 50pm thickness. broad internal friction peak at K accompanied by an The observed agreement indicates that the vibrating reed measurement can be successfully used for obtaining anisotropy constant.
Shui, H. Pei, Y. Liu, Relationship between the internal friction values of the specimen and the vibration system, Rev.
Instr. Let me comment suggestion of Marcus V. A description of this technique for measurement of internal friction and Young’s modulus in small metal samples will be published elsewhere.
Google Scholar; 7. Morse, Vibration and Sound (McGraw‐Hill Book Company, Inc., New York, ). Google Scholar; 8. A very sensitive apparatus using the vibrating reed technique in a magnetic field is described. This new technic is an internal friction measurement which has been developed and applied to the study of vortex pinning in high T_c type II superconductors.
The vibrating reed is simply used as a sample holder for the superconductor which can be oriented thin films, bulk samples or powders. A batch of 54 tropical species was analyzed using free-vibration and forced-released vibration tests.
The free-vibration tests were conducted by bending and compression using nylon thread or elastic thread as supports. The wood species used cover a broad spectrum of density values and were obtained from the CIRAD wood collection. Samples were stabilized at a mean moisture content of.
Fundamentals of Vibration Measurement and Analysis Explained Thanks to Peter Brown for this article. Introduction: The advent of the microprocessor has enormously advanced the process of vibration data acquisition and analysis in recent years.
Measurement tasks that took hours only two decades ago. The measurement and analysis of internal friction is commonly referred to as mechanical spectroscopy. This technique has been applied extensively to characterize bulk metals (see, for example, [ 7 – 10 ]), but little is known about internal friction.
A more convenient method of skin friction measurement is desired. Various experimental designs have been developed to measure the friction of skin (Sivamani and Maibach, ). To complete the list, an “imposed displacement” method to measure the dynamic coefficient of friction is proposed in this paper.
DEVELOPMENT OF THE VIBRATING REED INTERNAL FRICTION APPARATUS 1 2 4 5 Introduction 5 Description of the Vibrating Reed Apparatus 5 Computerization of the Vibrating Reed Apparatus 10 Summary of the Vibrating Reed Capabilities 13 3.
USE OF LINEAR REGRESSION TECHNIQUES IN ANALYSIS OF SINGLE On the determination of Young’s modulus of thin films with impulse excitation technique - Volume 32 Issue 3 - M.F. Slim, A. Alhussein, A. Billard, F. Sanchette, M. François Vibrating reed internal friction apparatus for films and foils.
Evaluation of measurement data—Guide to the expression of uncertainty in measurement (). Click on the book chapter title to read more. Vibration is the oscillation, or moving back and forth of an object. The word vibrations consciously or unconsciously use it as a measure of how well things are running.
For vibration to get start it takes some effort, either external or internal to get vibration going, some input of energy through an applied force. mechanical parts due to the effect of external or internal forces on that parts. Vibration measurement is an effective, non-intrusive method.
Vibration Analysis Techniques. Definitions. 1) Gross Errors. Gross errors are caused by mistake in using instruments or meters, calculating measurement and recording data results. The best example of these errors is a person or operator reading pressure gage N/m2 as N/m2.The types of mechanical faults which can occur on a given machine are well known to maintenance personnel.
What is needed is a straightforward message that a fault is developing, and an indication of its severity. If the expected machine fault is defined, you can easily pick the monitoring method which will provide the fastest, cheapest, and most reliable result.Multi-scale concrete model with rate-dependent internal friction.
29 February | European Journal of Environmental and Civil Engineering, Vol. 21, No. The effect of longitudinal tangential vibrations on friction and driving forces in sliding motion.
Tribology International, Vol. 55 Journal of Dynamic Systems, Measurement, and.