United States Patent
Morris et al.
US005817945A [ii] Patent Number: [45] Date of Patent:
[54] SYSTEM AND METHOD OF DETERMINING STRAIN
[75] Inventors: Martin Jesse Morris, Edwardsville, 111.; Kirk Sullivan Schanze,
Gainesville, Fla.
[73] Assignee: McDonnell Douglas
[21] Appl. No.: 631,955
[22] Filed: Apr. 15, 1996
[51] Int. C I. C011.1/24
[52] U.S. CI 73/800; 73/794; 73/762
[58] Field of Search 73/760, 762, 766,
73/791, 800, 802, 794
[56] References Cited
U.S. PATENT DOCUMENTS
3,715,915 2/1973 Williams 73/800
4,849,668 7/1989 Crawley et al 310/328
5,394,752 3/1995 Reda 73/800
5,490,426 2/1996 Shiga et al 73/762
5,546,811 8/1996 Rogers et al 73/762
5,559,358 9/1996 Burns et al 73/579
FOREIGN PATENT DOCUMENTS
2194062 2/1988 United Kingdom 73/762
Primary Examiner—Richard Chilcot
Assistant Examiner—Max H. Noori
Attorney, Agent, or Firm—Dale B. Hailing
[57] ABSTRACT
A system (50) for determining strain includes: a stimulating light source (54, 56); a device (64) for placing stress on an object (58); a number ol local strain gauges (66) attached to the object (58); and an image capturing device (62, 64). A controller (52) is coupled to the stimulating light source (54, 56) and has a signal that turns on the stimulating light source (54, 56). The controller (52) receives a strain signal from each of the local strain gauges (66) located on the object (58). The controller (66) has an image signal that determines when the image capturing device (62, 64) captures an image.
19 Claims, 4 Drawing Sheets
