Other

Micromotion Gmbh

Wilmut Brost

David T Hahn

Joseph D Titlow

Method and apparatus for determining Young's Modulus of a specimen by measuring the speed at which stress waves, either P-waves or S-waves, propagate therein. An embodiment of the apparatus includes two fixtures which are removably affixed to opposite ends of the specimen. A hammer having an accelerometer affixed to its head is used to strike the first fixture to produce stress waves in the specimen. A timing means starts counting in response to an output generated by the accelerometer when the hammer strikes the first fixture. A second accelerometer affixed to the second fixture detects the stress waves and generates an output which causes the timing means to stop counting. Further circuitry extracts the measured time, calculates a dispersion time delay based on material and length, and subtracts the dispersion time delay and a predetermined constant, both dependent on the material in the specimen, from the measured time to form a corrected transit time. The circuitry uses the corrected transit time to determine the propagation speed of the stress waves and Young's Modulus therefrom.

Method and apparatus for determining elastic constants in tubes

Method and apparatus for determining Young's Modulus of a specimen by measuring the speed at which stress waves, either P-waves or S-waves, propagate therein. An embodiment of the apparatus includes two fixtures which are removably affixed to opposite ends of the specimen. A hammer having an accelerometer affixed to its head is used to strike the first fixture to produce stress waves in the specimen. A timer starts counting in response to an output generated by the accelerometer when the hammer strikes the first fixture. A second accelerometer affixed to the second fixture detects the stress waves and generates an output which causes the timer to stop counting. Further circuitry extracts the measured time, calculates a dispersion time delay based on material and length, and subtracts the dispersion time delay and a predetermined constant, both dependent on the material in the specimen, from the measured time to form a corrected transit time. The circuitry uses the corrected transit time to determine the propagation speed of the stress waves and Young's Modulus therefrom.

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Northglenn, CO, United States of America

Wilmut Brost