Method and apparatus for determining material structural integrity

Patent · Sat Jan 01 04:00:00 EST 1994

OSTI ID:206402

Pechersky, M J

Disclosed are a nondestructive method and apparatus for determining the structural integrity of materials by combining laser vibrometry with damping analysis to determine the damping loss factor. The method comprises the steps of vibrating the area being tested over a known frequency range and measuring vibrational force and velocity vs time over the known frequency range. Vibrational velocity is preferably measured by a laser vibrometer. Measurement of the vibrational force depends on the vibration method: if an electromagnetic coil is used to vibrate a magnet secured to the area being tested, then the vibrational force is determined by the coil current. If a reciprocating transducer is used, the vibrational force is determined by a force gauge in the transducer. Using vibrational analysis, a plot of the drive point mobility of the material over the preselected frequency range is generated from the vibrational force and velocity data. Damping loss factor is derived from a plot of the drive point mobility over the preselected frequency range using the resonance dwell method and compared with a reference damping loss factor for structural integrity evaluation.

• Research Organization: Westinghouse Savannah River Co., Aiken, SC (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC09-89SR18035
• Assignee: Dept. of Energy
• Patent Number(s): PATENTS-US--A8194432
• Application Number: ON: DE96006454; PAN: 8-194,432
• OSTI ID: 206402
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
ACOUSTIC TESTING
BUILDING MATERIALS
DAMPING
DEFECTS
MECHANICAL VIBRATIONS
NONDESTRUCTIVE TESTING