Method for assessing the damage to a paint-covered composite material, measuring two separate criteria on the spectrogram

Patent metadata

Field	Value
Publication number	US-9797829-B2
Application number	US-201615098895-A
Country	US
Kind code	B2
Filing date	Apr 14, 2016
Priority date	Oct 17, 2013
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A method for assessing damage to a composite material covered with a polyurethane-type paint is provided. Two separate criteria are measured on a spectrogram obtained by infrared spectrometry, thereby characterizing thermal ageing of the paint, each separate criteria being a measurement on a curve of a spectrum of the spectrogram of a height of a particular peak, thereby giving two independent assessments of the thermal ageing. Then, the two separate criteria are combined together in order to obtain a result of a level of the damage.

First claim

What is claimed is:

1. A method for assessing damage to a composite material covered with a polyurethane-type paint comprising: bringing an apparatus into contact with the composite material, measuring two separate criteria on a same spectrogram obtained by infrared spectrometry, thereby characterizing thermal ageing of the paint, each separate criteria comprising a measurement on a curve of a spectrum of the same spectrogram of a height of a particular peak, thereby giving two independent assessments of the thermal ageing and combining the two separate criteria to obtain a result of a level of the damage to the composite material without destruction of the composite material.

2. The assessment method according to claim 1 , wherein in order to obtain a first criterion of the two separate criteria, the height of the particular peak is measured relative to a base line passing through a first two immediately adjacent troughs on each side of the peak.

3. The assessment method according to claim 1 , wherein in order to obtain a second criterion of the two separate criteria, the height of the particular peak is measured relative to a base line passing through a first two significant troughs on each side of the peak.

4. The assessment method according to claim 1 , wherein the two separate criteria are disposed along two axes of a graph in order to determine a level of thermal degradation of the composite material.

5. The method according to claim 1 , wherein a wave number of the particular peak is about 1300/cm.

6. The method according to claim 5 , wherein a wave number of the particular peak is between 1288 and 1314/cm.

7. The assessment method according to claim 5 , wherein in order to obtain a first criterion of the two separate criteria, the height of the particular peak is measured relative to a base line passing through a first two immediately adjacent troughs on each side of the peak, and in order to obtain the first criterion, a first trough of one of the adjacent troughs between 1322 and 1374/cm is considered, and a second trough of the adjacent troughs between 1236 and 1247/cm is considered, the value 1247/cm being retained if the second trough is not pronounced on the curve.

8. The assessment method according to claim 5 , wherein in order to obtain a first criterion of the two separate criteria, the height of the particular peak is measured relative to a base line passing through a first two immediately adjacent troughs on each side of the peak, and in a case where the particular peak is no longer observable, a largest height between the base line and the curve is measured between 1288 and 1314/cm, in order to obtain the first criterion that is negative.

9. The assessment method according to claim 5 , wherein in order to obtain a second criterion of the two separate criteria, the height of the particular peak is measured relative to a base line passing through a first two significant troughs on each side of the peak, and in order to obtain the second criterion, a first significant trough between 1951 and 2051/cm and a second significant trough between 901 and 1102/cm are considered.

10. The assessment method according to claim 9 , wherein in a case where the particular peak is no longer observable, then a height between the base line and the curve at a 1288/cm value is measured, in order to obtain the second criterion.

Assignees

• Aircelle Sa

Inventors

• Baillard Andre
• Lefeu Odile
• Joubert Frederic
• Piel Emmanuel

Classifications

• G01N21/95

  characterised by the material or shape of the object to be examined (G01N21/89 - G01N21/91, G01N21/94 take precedence) · CPC title

• G01N21/8422

  Investigating thin films, e.g. matrix isolation method · CPC title

• G01N21/8851

  Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges (G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002) · CPC title

• G01J3/28

  Investigating the spectrum (using colour filters G01J3/51) · CPC title

• G01N25/72

  Investigating presence of flaws · CPC title