Apparatus for measuring surface movement of an object that is subjected to external vibrations
Abstract
A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accuratelymore »
- Inventors:
- Issue Date:
- Research Org.:
- Surface Combustion Inc
- OSTI Identifier:
- 504941
- Patent Number(s):
- 5623307
- Application Number:
- PAN: 8-381,201
- Assignee:
- Textron Defense Systems, Wilmington, MA (United States)
- DOE Contract Number:
- FC07-89ID12830
- Resource Type:
- Patent
- Resource Relation:
- Other Information: PBD: 22 Apr 1997
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; INTERFEROMETERS; NONDESTRUCTIVE TESTING; PROCESS CONTROL; SOUND WAVES; MECHANICAL VIBRATIONS; SURFACE PROPERTIES; SIGNAL CONDITIONERS; TEMPERATURE MEASUREMENT; TEMPERATURE CONTROL; MACHINE PARTS; PHOTOMULTIPLIERS
Citation Formats
Kotidis, P A, Woodroffe, J A, and Rostler, P S. Apparatus for measuring surface movement of an object that is subjected to external vibrations. United States: N. p., 1997.
Web.
Kotidis, P A, Woodroffe, J A, & Rostler, P S. Apparatus for measuring surface movement of an object that is subjected to external vibrations. United States.
Kotidis, P A, Woodroffe, J A, and Rostler, P S. Tue .
"Apparatus for measuring surface movement of an object that is subjected to external vibrations". United States.
@article{osti_504941,
title = {Apparatus for measuring surface movement of an object that is subjected to external vibrations},
author = {Kotidis, P A and Woodroffe, J A and Rostler, P S},
abstractNote = {A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Apr 22 00:00:00 EDT 1997},
month = {Tue Apr 22 00:00:00 EDT 1997}
}