Method and apparatus for determining material structural integrity

Patent · Mon Jan 01 04:00:00 EST 1996

OSTI ID:870432

Pechersky, Martin ^[1]

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1. Aiken, SC

A non-destructive method and apparatus for determining the structural integrity of materials by combining laser vibrometry with damping analysis techniques to determine the damping loss factor of a material. The method comprises the steps of vibrating the area being tested over a known frequency range and measuring vibrational force and velocity as a function of 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 amount of coil current used in vibrating the magnet. If a reciprocating transducer is used to vibrate a magnet secured to the area being tested, then the vibrational force is determined by a force gauge in the reciprocating transducer. Using known vibrational analysis methods, a plot of the drive point mobility of the material over the preselected frequency range is generated from the vibrational force and velocity measurements. The 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
• DOE Contract Number: AC09-89SR18035
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 5520052
• OSTI ID: 870432
• Country of Publication: United States
• Language: English

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