The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 17, 1997
Filed:
Oct. 23, 1995
Lloyd C Bobb, Horsham, PA (US);
Howard D Krumboltz, Chalfont, PA (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
A sensor and method are disclosed for determining if a region, defined by two end points, in a structure has exceeded a predetermined amount of strain. The sensor has an optical waveguide which has two ends for receiving and emitting light and which is fixable at two locations thereon to respective ones of the end points to define a sensing region therebetween. The sensing region has a first portion with a first length and a first cross-sectional area, and a second portion with a second length and a second cross-sectional area which is smaller than the first cross-sectional area. The lengths and cross-sectional areas are sized so that the optical waveguide has a strain failure point equal to the predetermined amount of strain. The lengths and cross-sectional areas are approximately sized according to the formula R=.alpha.+1/ (.alpha./.beta.+1), wherein R=the ratio of the amount of strain in the second portion which will cause the optical waveguide to fail to the predetermined amount of strain in the structure, .alpha.=the ratio of the length of the first portion to the length of the second portion, and .beta.=the ratio of the cross-sectional area of the first portion to the cross-sectional area of the second portion.