In-process monitoring, automated decision-making, and process control for composite manufacturing using part-referenced ply-by-ply infrared thermography and other non-contact non-destructive inspection

Patent metadata

Field	Value
Publication number	US-2017350764-A1
Application number	US-201715685684-A
Country	US
Kind code	A1
Filing date	Aug 24, 2017
Priority date	Dec 7, 2015
Publication date	Dec 7, 2017
Grant date	—

Abstract

Method and apparatus for detecting defects in a composite is provided. After a ply of material for a workpiece is positioned, thermal energy is applied to a top surface of the ply of material, and a digital thermographic camera captures images of the top surface. A computer processor determines heat characteristics of the top surface to identify regions of the top surface with different heat characteristics. Such different areas are identified as regions that include a defect. The defect regions can be repaired prior to disposing additional plies of material over previously-applied plies.

First claim

What is claimed is:

1 . A method, comprising:
laying a first ply of material; applying thermal energy to a surface of the first ply of material; capturing at least one digital thermographic image of the surface of the first ply of material after applying the thermal energy; using a computer processor, analyzing at least one heat characteristic of regions of the first ply of material in the at least one digital thermographic image to identify defect regions in which the at least one heat characteristic is different than baseline data; upon identifying a defect region, outputting an alert; halting processing to allow the defect region to be corrected; resuming processing; and laying a second ply of material on the first ply of material after resuming processing.

2 . The method of claim 1 , further comprising curing the first ply of material and the second ply of material after laying the second ply of material.

3 . The method of claim 1 , wherein analyzing at least one heat characteristic in the at least one digital thermographic image comprises analyzing at least one heat characteristic of every pixel in the at least one digital thermographic image.

4 . The method of claim 1 , wherein the at least one heat characteristic comprises at least one of respective temperatures of the regions, respective first derivative rates of change of temperature of the regions over a plurality of digital thermographic images, and respective second derivative rates of change of temperature of the regions over a plurality of digital thermographic images, and wherein the at least one heat characteristic of a subject region is different than surrounding regions if a peak of a second derivative rate of change of temperature for the subject region differs in time from a peak of a second derivative rate of change of temperature of at least one surrounding regions by more than a threshold amount.

5 . The method of claim 1 , further comprising:
determining that the second ply of material does not include a defect; and updating the baseline model based on a digital thermographic image of a surface of the second ply of material.

6 . The method of claim 1 , further comprising reinspecting the first play of material after resuming processing.

7 . The method of claim 1 , wherein the alert includes an indication of a location of the defect region on the first ply.

8 . A system, comprising:
a work surface for arranging and compacting uncured composite layers; a heat source arranged relative to the surface and operable to provide thermal energy to a surface of a first ply of material on the work surface; a thermographic digital camera arranged relative to the surface and operable to capture at least one digital thermographic image of the surface of the first ply of material; a computer processor in communication with the thermographic digital camera and the heat source; and a computer memory containing a program that, when executed on the computer processor, performs an operation for processing data, comprising:
applying thermal energy to a surface of the first ply of material;
capturing at least one digital thermographic image of the surface of the first ply of material after applying the thermal energy;
analyzing at least one heat characteristic of regions of the first ply of material in the at least one digital thermographic image to identify defect regions in which the at least one heat characteristic is different than baseline data;
upon identifying a defect region, outputting an alert;
halting processing to allow the defect region to be corrected;
resuming processing; and
laying a second ply of material on the first ply of material after resuming processing.

9 . The system of claim 8 , wherein the program, when executed on the computer processor, performs an additional operation for processing data, comprising, upon receiving an indication of a repair being made to the defect region:
outputting a second signal to the heat source to apply a second thermal energy to the surface of the first ply; capturing a second at least one digital thermographic image of the surface of the first ply after applying the second thermal energy; analyzing at least one heat characteristic of regions of the first ply in the second at least one digital thermographic image to identify defect regions in which the at least one heat characteristic is different than surrounding regions.

10 . The system of claim 8 , wherein analyzing at least one heat characteristic of the first ply in the at least one digital thermographic image to identify regions in which the at least one heat characteristic is different than surrounding regions comprises analyzing at least one heat characteristic of every pixel in the at least one digital thermographic image.

11 . The system of claim 8 , wherein the at least one heat characteristic of the first ply comprises at least one of respective temperatures of the regions, respective first derivative rates of change of temperature of the regions over a plurality of digital thermographic images, and respective second derivative rates of change of temperature of the regions over a plurality of digital thermographic images.

12 . The system of claim 11 , wherein the at least one heat characteristic of a subject region is different than surrounding regions if a peak of a second derivative rate of change of temperature for the subject region differs in time from a peak of a second derivative rate of change of temperature of at least one surrounding regions by more than a threshold amount.

13 . The system of claim 18 , wherein comparing the digital thermographic image of a surface of the first ply of material to the baseline data comprises determining whether a rejectable flaw exists and determining whether a sub-rejectable flaw exists.

14 . The system of claim 8 , wherein the alert includes an indication of a location of the defect region.

15 . A method, comprising:
laying a first ply of material; applying thermal energy to a surface of the first ply of material; capturing at least one digital thermographic image of the surface of the first ply of material after applying the thermal energy; using a computer processor, analyzing at least one heat characteristic of regions of the first ply of material in the at least one digital thermographic image to identify defect regions in which the at least one heat characteristic is different than baseline data; upon identifying a defect region, outputting an alert; correcting the defect region; and laying a second ply of material on the first ply of material after resuming processing.

16 . The method of claim 15 , further comprising:
capturing a digital thermographic image of a surface of the second ply of material; and comparing the digital thermographic image of a surface of the second ply of material to the baseline data.

17 . The method of claim 15 , further comprising:
determining that the second ply of material does not include a defect; and updating the baseline model based on the digital thermographic image of a surface of the second ply of material.

18 . The method of claim 16 , wherein comparing the digital thermographic image of a surface of the second ply of material to the baseline data comprises determining whether a rejectable flaw exists and determining whether a sub-rejectable flaw exists.

19 . The method of claim 18 , wherein if a sub-rejectable flaw exists, further comprising laying a third play of material on the second play of

Assignees

• Boeing Co

Inventors

• Thompson Jeffrey G
• Georgeson Gary E

Classifications

• G01J2005/0077

  Imaging · CPC title

• G01J2005/0081

  Physics · mapped topic

• G01J5/10 Primary

  using electric radiation detectors · CPC title

• G01J5/48 Primary

  Thermography; Techniques using wholly visual means · CPC title

• G01N25/72

  Investigating presence of flaws · CPC title