Method for resonant measurement
AssigneeQuatro Corporation
InventorGeorge W. Rhodes
Life of this patent
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Abstract
A method of measurement of objects by resonant ultra sound is used to determine object surface to near surface flaws. First, the frequency for expected degenerate surface acoustic wave responses is determined for one or more input frequencies and then splitting of degenerate resonant modes are observed to identify the presence of surface flaws in the object.
Claims15
A method for determination of surface conditions in objects comprising the steps of:
- a. mathematically determining degenerate modes which are dependant only upon surface acoustic waves and which have degenerate resonant frequencies;
- b. examining object resonance in at least one frequency region determined to exhibit degeneracy;
- c. observing a deviation from determined degenerate resonances;
- and
- d. identifying objects which exhibit unacceptale deviations from the mathematically determined degenerate modes.
A method of detecting surface defects in a ball-shaped test object comprising the steps of:
- a. determining from a wave equation for a sphere, resonant modes which are unique only for surface acoustic waves of said test object;
- b. identifying at least one frequency where a resonant mode unique for only said surface waves exists, for said test object;
- c. applying a plurality of vibrations to said test object where one of said vibrations is at said frequency;
- d. analyzing of resonant amplitude versus said frequency;
- and
- e. identifying as defective ball-shaped test objects which exhibit a distorted resonant mode where said identified one frequency mode should be observed.
A method for characterizing surface defects of an object by resonant ultrasound spectroscopy comprising the steps of:
- a. identifying by mathematical analysis frequencies at which only surface acoustical waves are generated;
- b. applying to said object acoustic waves having different frequencies, one of which is at said identified only surface acoustic wave frequency;
- c. detecting the resonant response of said object at each of said frequencies;
- and
- d. determining the presence of a surface defect by comparing the response of a substantially perfect test object to the response of said object.
A method for testing surface defects of an object comprising the steps of:
- a. identifying at least one surface acoustic wave resonant mode for said object;
- b. applying a spectrum of vibration frequencies which includes only surface acoustic wave mode frequencies to said object;
- c. analyzing response of said object to determine deviation of said response from a known predetermined acceptable objects;
- and
- d. accepting or rejecting said object based upon deviation from said one surface acoustic wave resonant mode for said object.
Dependencies are inferred from the claim text.