Method for measuring stress
First Claim
Patent Images
1. A method for measuring stress magnitude distributed in a substance comprising the steps of:
- inputting elastic waves to a substance so as to irradiate a desired portion thereof;
receiving output waves which are transmitted and/or reflected from said substance;
comparing said input waves with said output waves associated with analyzing attenuation factors of said input and output waves being converted into frequency values to define transfer functions of said waves; and
defining said stress magnitude as an increment of said transfer functions between said output and input waves for providing a quantitative measurement of said stress.
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Abstract
Stress in a substance is measured by utilizing the transfer characteristics of elastic waves, such that elastic waves input to a substance are displaced by the stress load within the substance. Waves input to the substance and output therefrom by transmission or reflection are compared by fast fourier transform analysis, obtaining a wave attenuation factor quantifying the magnitude of stress in the substance.
21 Citations
20 Claims
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1. A method for measuring stress magnitude distributed in a substance comprising the steps of:
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inputting elastic waves to a substance so as to irradiate a desired portion thereof; receiving output waves which are transmitted and/or reflected from said substance; comparing said input waves with said output waves associated with analyzing attenuation factors of said input and output waves being converted into frequency values to define transfer functions of said waves; and defining said stress magnitude as an increment of said transfer functions between said output and input waves for providing a quantitative measurement of said stress. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for measuring stress magnitude distributed in a substance, comprising:
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a signal generating means for generating an input electric signal; a first transducing means for converting said input electric signal to elastic waves and inputting said waves to a substance so as to irradiate a desired portion thereof; a second transducing means for receiving output waves from said substance and converting said output waves to an output electric signal; an amplifying means for amplifying said output electric signal to obtain an amplified electric signal; a recording means for recording both of said input and amplified electric signals transferred from said generating means and said amplifying means, an analyzing means for comparing said recorded signal from the generating means with that from the amplifying means associated with analyzing wave attenuation factors of both of said input and amplified electric signals being converted into frequency values to define transfer functions of said input and amplified electric signals, a display means for displaying the frequency values of said transfer functions as a quantitative value of said stress, and a computer for calculating an increment of a transfer function between said input and amplified electric signals to define stress magnitude distributed in said substance, and for issuing commands to said signal generating means, said first and second transducing means, said amplifying means, said recording means, said analyzing means and said display means. - View Dependent Claims (15, 16, 17, 18)
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19. A method for measuring stress magnitude distributed in a substance, comprising the steps of:
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inputting elastic waves to a substance so as to irradiate a desired portion thereof; receiving output waves which are transmitted and/or reflected from said substance; comparing said input waves with said output waves associated with analyzing attenuation factors of said input and output waves being converted into frequency values to define transfer functions of said waves; processing the transfer functions by fast fourier transformation such that the transfer functions are converted from a time domain to a frequency domain; and defining said stress magnitude in said substance as an increment of said transfer functions between said output and input waves for providing a quantitative measurement of said stress.
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20. An apparatus for measuring stress magnitude distributed in a substance, comprising
a signal generating means for generating an input electric signal; -
a first transducing means for converting said input electric signal to an elastic wave and inputting said wave to a substance so as to irradiate a desired portion thereof; a second transducing means for receiving a wave output from said substance and converting said wave to an output electric signal; an amplifying means for amplifying said output electric signal to obtain an amplified electric signal; a recording means for recording both of said input and amplified electric signals transferred from said generating means and said amplifying means; an analyzing means for comparing said recorded signal from the generating means with that from the amplifying means associated with analyzing wave attenuation factors of both signals being converted into frequency values to define transfer functions of said input and amplified electric signals, said analyzing means processing the transfer functions by fast fourier transformation such that the transfer functions are converted from a time domain to a frequency domain; a display means for displaying the frequency values of said transfer functions as a quantitative value of said stress; and a computer for calculating an increment of said transfer function between said input and amplified electric signals to define stress magnitude distributed in said substance, and for issuing commands to said signal generating means, said first and second transducing means, said amplifying means, said recording means, said analyzing means and said display means.
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Specification