Jerry D Saunders

US Patent:

44793863, Oct 30, 1984

Filed:

Feb 10, 1983

Appl. No.:

6/465366

Inventors:

James M. Beggs - Washington DC
Garland D. Johnston - Huntsville AL
Archie D. Coleman - Huntsville AL
Joseph N. Portwood - Decatur AL
Jerry M. Saunders - Huntsville AL
John W. Redmon - Huntsville AL
Allen C. Porter - Madison AL

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

G01M 700
G01N 2904

US Classification:

73582

Abstract:

A method and a system for testing the bonding of foam insulation (22) attached to metal. The system involves the use of an impacter (10) which has a calibrated load cell (12) mounted on a plunger (14) and a hammer head (16) mounted on the end of the plunger (14). When the impacter (10) strikes the insulation (22) at a point to be tested, the load cell (12) measures the force of the impact and the precise time interval during which the hammer head (16) is in contact with the insulation (22). This information is transmitted as an electrical signal (20) to a load cell amplifier (28) where the signal (20) is conditioned and then transmitted to a Fast Fourier Transform (FFT) analyzer (34). The FFT analyzer (34) produces energy spectral density curves (power plotted against frequency in Hertz) which are displayed on a video screen (39). An operator, by observing the frequency point at which the curve terminates, may determine the quality of the bond.