Measuring and testing – Vibration – Resonance – frequency – or amplitude study
Patent
1993-09-08
1996-01-23
Chilcot, Richard
Measuring and testing
Vibration
Resonance, frequency, or amplitude study
73599, 73630, 374117, G01H 1300
Patent
active
054857503
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a process for determining the value of parameters which change the resonance frequency of microstructures.
In J. Microwave Power (1987) pages 85 to 93 various processes for contact-free temperature measurements of objects whose temperature is to be determined but which are not directly accessible are described. In each case a glass fiber is brought close to the object whose temperature is to be measured. By measuring the temperature-dependent fluorescence properties of a fluorescent substance disposed on the object to be measured the temperature at the measuring location can be deducted. These processes however have the disadvantage that a glass fiber has to be brought into close proximity, that is, to no more than about 10 mm, to the object to be measured.
U.S. Pat. No. 3,596,069 discloses a similar process by which the resonance frequency of a cylindrical body is determined. Herefrom the frequency determining parameters are obtained. Further, from the German Patent Publication De 30 12 774 A1 it is known to excite a test body with ultrasonic radiation, whereupon the amplitude of the resonance frequency is measured. From the deviation of the resonance frequency amplitude from a predetermined value, the presence of a defect within the body is determined.
British Patent Publication GB 21 43 036A describes a method for the detection of intergranular defects of test pieces wherein ultrasound echoes of perfect pieces are registered as standard values. A comparison of the ultrasound echoes of faulty test pieces with the standard value gives an indication of the degree of faultiness. However, this procedure is not suitable for thin membranes because the travel distances of the sound within the membrane are too short.
Another method of this type is known from the U.S. book "Ultrasonic Testing" published by F. Szilard, 1982, pages 432-436.
Finally, in the Journal of the Acoustical Society of America, Vol. 80, No. 6, December 1986, pages 1762 to 1776, the resonance scattering of ultrasound in various layers is described.
It is the object of the present invention to provide a process which facilitates measurement of temperatures, expansion, pressures, densities, flow speeds, coating rates, internal mechanical strain and modules of elasticity of objects which are not directly accessible during measurement without the need for bringing circuit points or conductors in close proximity to the object to be measured during the measuring procedure.
SUMMARY OF THE INVENTION
In a process for finding the value of parameters which change the resonance frequencies of microstructures wherein the microstructures include at least one membrane mounted at its periphery and wherein at least one resonance frequency of the microstructures is between 100 kHz and 100 MHz, the frequency of the characteristic resonance frequency of the microstructures is detected by exposing the microstructures to ultrasound and measuring the intensity of the ultrasound transmitted through, or reflected from, the microstructure and the value of the parameter is then determined by means of a calibration curve.
BRIEF DESCRIPTION OF DRAWINGS
The invention will now be described in greater detail on the basis of FIGS. 1 to 6.
Wherein FIG. 1 shows schematically an arrangement for determining the frequency and
FIG. 2 shows the absorption of ultrasound depending on the frequency.
FIGS. 3 to 6 show examplary embodiments of microstructures.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first embodiment describes measurement of temperature with a structured titanium membrane which is freely stretched over a rigid frame.
In accordance with the method described in EP 0 104 685 honeycomb-shaped microstructures 1 were made on a titanium membrane 2 of 3 .mu.m thickness freely stretched over a rigid frame 3. The rigid frame 3 was circular with an outer diameter of 40 mm and an inner diameter of 25 mm and consisted of a 6 mm thick iron-nickel alloy structure having a linear thermal expansion coefficient of about 5
REFERENCES:
patent: 3355933 (1967-12-01), Rowe
patent: 4297872 (1981-11-01), Ikeda et al.
patent: 4297884 (1981-11-01), Leverque et al.
patent: 4400980 (1983-08-01), Lepert
patent: 4607341 (1986-08-01), Monchalin
Bach Klaus J.
Chilcot Richard
Kernforschungszenlrum Karlsruhe GmbH
McCall Eric S.
LandOfFree
Process for finding the value of parameters capable of changing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for finding the value of parameters capable of changing , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for finding the value of parameters capable of changing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1498664