Research/Patents/US 4838085
US 4838085

METHODS AND APPARATUS FOR NON-DESTRUCTING EVALUATION OF THE MECHANICAL PROPERTIES OF COMPOSITE MATERIALS

Assignee

WASHINGTON STATE UNIVERSITY RESEARCH FOUNDATION C.

Filed

Mar 25, 1986

Granted

Jun 13, 1989

Location

PULLMAN WA US

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.

Source: Google Patents

35 USC §181 Secrecy Order

Imposed

Sep 5, 1986

Rescinded

May 20, 1987

Duration

8 months

Inventor

  • 1ROY F. PELLERIN

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Back to patent indexSource: USPTO 35 USC §181 secrecy order records