A SYSTEM AND METHOD OF DETERMINING POROSITY IN COMPOSITE MATERIALS USING ULTRASOUND

Title:

A SYSTEM AND METHOD OF DETERMINING POROSITY IN COMPOSITE MATERIALS USING ULTRASOUND

Document Type and Number:

WIPO Patent Application WO2002006814

Kind Code:

A3

Abstract:

The invention provides for ultrasonically measuring the porosity in a sample composite material by accessing only one side of the sample composite material and includes the steps of measuring a sample ultrasonic signal from the sample composite material, normalizing the sample ultrasonic signal relative to the surface echo of the sample composite material, and isolating a sample back-wall echo signal from the sample ultrasonic signal. A sample frequency spectrum of the sample back-wall ultrasonic signal is then determined. Next, the method and system include the steps of measuring a reference ultrasonic signal from a reference composite material, normalizing the reference ultrasonic signal relative to the surface echo of the reference composite material; and isolating a reference back-wall echo signal from the sample ultrasonic signal. A reference frequency spectrum of the reference back-wall ultrasonic signal is then determined. The invention further includes deriving the ultrasonic attenuation of the sample ultrasonic signal as the ratio of the sample frequency spectrum to the reference frequency spectrum over a predetermined frequency range. Comparing the derived ultrasonic attenuation to predetermined attenuation standards permits evaluating the porosity of the sampled composite material.

Inventors:

DUBOIS MARC
LORRAINE PETER W
DRAKE THOMAS E JR
FILKINS ROBERT J
DEATON JOHN B JR

Application Number:

PCT/US2001/022156

Publication Date:

September 26, 2002

Filing Date:

July 13, 2001

Export Citation:

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Assignee:

LOCKHEED CORP (US)

International Classes:

G01N15/08; G01N29/11; G01N29/00; G01N29/24; G01N29/46; (IPC1-7): G01N29/10; G01N29/24

Domestic Patent References:

WO1998022814A1	1998-05-28
WO1998022801A1	1998-05-28

Foreign References:

US5608166A

1997-03-04

Other References: