Method and means to analyze thermographic data acquired during automated fiber placement

Patent metadata

Field	Value
Publication number	US-11373264-B2
Application number	US-202017121264-A
Country	US
Kind code	B2
Filing date	Dec 14, 2020
Priority date	Apr 17, 2017
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

A method of detecting defects in a composite structure includes applying heat to a surface of a composite structure. Thermographic images or frames captured by a moving camera may be utilized to corm temporally aligned images that include temperature data (pixels) from a plurality of frames, wherein the pixels comprise data captured at a simple (uniform) time delay from the time at which heat was applied. The temporally aligned thermographic data for the surface region may include variations due to differences in thermal transients caused by defects in the composite structure. The variations in the thermographic data may be utilized to detect one or more defects in the composite structure.

First claim

What is claimed is:

1. A method of evaluating physical properties of a fiber reinforced composite structure, the method comprising:
heating at least a portion of the composite structure using a heat source that moves relative to the composite structure;
capturing a series of groups of thermographic image data of the surface of the composite structure after heating the composite structure using a thermographic camera that moves relative to the composite structure;
time shifting thermographic image data from a plurality of the groups of thermographic image data to form at least one temporally synchronized image comprising thermographic image data for a surface region at equal times from heating; and
utilizing variations in the at least one thermographic synchronized image to identify defects in the composite structure.

2. The method of claim 1 , including:
applying a tow to a heated surface of the composite structure;
capturing thermographic image data from a surface of the tow after the tow has been applied to the heated surface.

3. The method of claim 1 , including:
forming a plurality of temporally synchronized images; and
comparing the temporally synchronized images to determine if defects are present in the composite structure.

4. The method of claim 3 , wherein:
the groups of thermographic image data comprise frames having a plurality of pixels, the frames forming a data cube having two spatial dimensions and one time dimension; and
wherein pixels are time shifted to align heating curves of the pixels to form the temporally synchronized images.

Assignees

• Nasa
• Us Adminstrator Of Nasa

Inventors

• Juarez Peter D
• Gregory Elizabeth D
• Cramer K Elliott

Classifications

• H04N23/23

  from thermal infrared radiation · CPC title

• G06T1/0014 Primary

  Image feed-back for automatic industrial control, e.g. robot with camera (robots B25J19/023) · CPC title

• B29C70/382 Primary

  Automated fiber placement [AFP] · CPC title

• G01J5/047

  Mobile mounting; Scanning arrangements · CPC title

• G01N25/72

  Investigating presence of flaws · CPC title