Apparatus for measuring surface movement of an object that is subjected to external vibrations
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.
- Research Organization:
- Surface Combustion Inc
- DOE Contract Number:
- FC07-89ID12830
- Assignee:
- Textron Defense Systems, Wilmington, MA (United States)
- Patent Number(s):
- US 5,623,307/A/
- Application Number:
- PAN: 8-381,201
- OSTI ID:
- 504941
- Resource Relation:
- Other Information: PBD: 22 Apr 1997
- Country of Publication:
- United States
- Language:
- English
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Apparatus for measuring surface movement of an object that is subjected to external vibrations
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Related Subjects
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