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:
Apr. 25, 1995
Filed:
Feb. 01, 1993
John M Webster, Forest Hills, NY (US);
Holographics Inc., Long Island City, NY (US);
Abstract
A semi-monocoque structure is nondestructively tested by affixing an exciter to the outer skin of the structure for causing it to vibrate with an out-of-plane motion in a nodal pattern. Sensors either attached to or spaced from the outer surface provide signals representative of phase and acceleration information at likely anti-nodal points from which a computer-programmed controller senses resonant frequencies and amplitude of displacement. The controller automatically scans the excitation frequency through a predetermined range, and upon sensing a resonant frequency examines the signal to ascertain phase and amplitude of displacement of the anti-nodes and automatically adjusts their amplitude of displacement until the anti-nodes are optimized to be either bi-concave or concave/convex. When it has sensed optimum conditions, the controller twice triggers the Pockels cell of a double-pulse holographic camera at times of maximum plus and maximum minus displacement, respectively, whereby the resulting overlaid holograms are synchronized to points of maximum displacement of the anti-nodal pattern. It is from the fringe map of resulting interference patterns contouring the anti-nodal patterns that faults are interpreted.