Measuring and testing – Vibration – By mechanical waves
Patent
1979-12-26
1982-01-12
Gill, James J.
Measuring and testing
Vibration
By mechanical waves
73659, 73801, G01N 308, G01N 2900, G01N 2700
Patent
active
043099033
ABSTRACT:
A method and apparatus for analyzing selected properties of a ferromagnetic material by magnetically inducing acoustic emissions in the material. The acoustic emission response is measured at a plurality of values of a selected response parameter, the response parameter being characterized by an acoustic emission response which, for each of its selected values, varies in mutual nonlinearity with the acoustic emission responses for the other selected values. The measured acoustic emission responses are compared to each other and to standard responses, thereby providing a more reliable measurement of the selected property than is attainable by analyzing at only one value of the response parameter. Comparing the ratio between acoustic emission responses at different values of the selected response parameter, with standard response ratios for the same response parameter values, further enhances reliability of the measurement.
In preferred embodiments the selected response parameter is the frequency of the acoustic emission response, the signal threshold level for obtaining an acoustic emission count rate, or the magnetic field strength. Properties selected for analysis in the preferred embodiments are stress, plastic deformation, microstructure and chemical composition.
The invention further includes structure in which transducers for measuring acoustic emission responses at different response parameter values are coupled to a specimen by a unitary coupling mechanism, thereby reducing spurious differences between the measurements at the various response parameter values.
REFERENCES:
patent: 4064735 (1977-12-01), Hutchison et al.
"Application of Correlation Analysis to Acoustic Emissions" by Ono et al., from Acoustic Emissions, ASTM STP 505, 1972, pp. 152-163.
"Acoustic Emission Behavior of Aluminum Alloys" by Ono et al., from Materials Evaluation, pp. 32-44, Feb. 1976.
"AE Characteristics and Stress Dependency of Magnetization Process . . . " by Kusanagi et al., published in The Proceedings of the First Nat'l Conference on Acoustic Emission," pp. 157-162, Dec. 1977, Tokyo.
"Identification of Acoustic Emission Source Mechanisms by Energy Spectrum Spectrum Analysis" by Woodward from Ultrasonics, Nov. 1976, pp. 249-255.
"Physical Acoustics Principles and Methods" by Mason et al., vol. XI, Chapter 6, Academic Press, 1975.
"Measurement of Residual Stress Using Magnetic Barkhausen Noise Analysis" by Matzkanin et al., Proceedings of ARPA/AFML Rev. of Quantitative NDE, 1-1976.
Gill James J.
The Regents of the University of California
LandOfFree
Method and apparatus for analyzing selected material properties does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for analyzing selected material properties , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for analyzing selected material properties will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1536353