Measuring and testing – Vibration – By mechanical waves
Patent
1986-03-25
1989-06-13
Levy, Stewart J.
Measuring and testing
Vibration
By mechanical waves
G01N 2900
Patent
active
048380857
ABSTRACT:
Methods and apparatuses for non-destructively testing and evaluating mechanical properties of composite materials such as particleboard, plywood, graphic fiber-epoxy composites and other bonded composite materials. The composite material structural elements are subjected to an impact, force or other stress wave producing stimulus. The resulting stress wave is sensed at two different points in time. The speed and attenuaton rate of the stress wave are determined. Measurements of the composite material density are combined with the stress wave speed and attenuation rate into an equation also defined by predetermined experimentally derived parameters. The experimentally derived parameters are specific to the test system, materials, and structural elements being tested. Apparatuses disclosed have sensors which are positioned to determine the stress wave intensity at spaced positions from the stress wave inducing device. The sensors can be retractably mounted and arranged in concentric circles. A singular magnetic sensor for repeatedly detecting a stress wave reflected within a bar or panel is also disclosed.
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Pellerin Roy F.
Ross Robert J.
Arana Louis M.
Levy Stewart J.
Washington State University Research Foundation, Inc.
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