Measuring and testing – Vibration – Sensing apparatus
Patent
1993-11-24
1996-04-09
Williams, Hezron E.
Measuring and testing
Vibration
Sensing apparatus
73579, 73655, G01N 2900
Patent
active
055050905
ABSTRACT:
Apparatus for non-destructively inspecting for faults in or beneath the surface of structures, such as debonds or delaminations in composite materials, or cracks, broken stringers, delaminations and the like in semi-monocoque structures, includes at least one spark gap discharge device displaced from the test object which focuses an acoustic pulse onto a small local area of the object for vibrationally exciting the surface of that area. A laser Doppler camera system, also displaced from the test object directs a laser beam onto the excited area and derives from light energy reflected back from the excited area the velocity of out-of-surface displacement of, and relaxation frequencies generated by, the surface of the excited area and provides an indication of whether a fault is present in that area. Acoustic pulses and the laser beam are directed to successive local areas in synchronism according to a scanning pattern, at each of which the reflected light energy is analyzed, following which the acquired data is processed and visually displayed in a manner which clearly indicates the presence of a fault and its location and enables the operator to further analyze the data to ascertain the type and extent of the fault.
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Holographics Inc.
Kwok Helen C.
Williams Hezron E.
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