Holomoire strain analyzer
AssigneeIllinois Institute of Technology
InventorCesar A. Sciammarella
Life of this patent
Estimating the term…
Abstract
A system and process for the measurement of strains in objects using holographic interferometry comprising a continuous point light source for illuminating the object, a fringe stabilizer for compensating for the vibratory motion of the object, a detector for capturing a holographic image, a rigid body motion compensator for compensating for the rigid body motion of the object caused by displacement of the object upon application of a force, and an electronic system for reconstructing the holographic image to permit comparison of the object before and after application of a force.
Claims16
A system for the measurement of strains in an object comprising:
- a continuous point source illumination means for illuminating at least a portion of a surface of said object, said continuous point source illumination means producing symmetric double illumination in at least two orthogonal directions and comprising at least one continuous laser, at least three optical fibers and a coupler connecting an outlet of said laser to one end of each said optical fiber;
- fringe stabilization means for compensating for vibratory motion of said object, said fringe stabilization means comprising a fringe stabilization detector receiving reflected light from said object and providing a signal to said fringe stabilization circuit, and said fringe stabilization circuit adjusting the phase of said light emitted by one of said optical fibers, maintaining a constant relationship between the phase of said light and the phase of a reference light emitted by another of said optical fibers;
- detector means for capturing a holographic image of said object;
- compensation means for compensating for displacement of said object;
- and
- processing means for electronically reconstructing said holographic image.
A process for measuring strains in an object comprising:
- illuminating at least a portion of a surface of said object with at least two symmetrically disposed continuous light point sources in one of two orthogonal directions, one of said continuous light point sources producing a reference light;
- adjusting the phase of light from said other continuous light point source to maintain a constant relationship with the phase of said reference light;
- capturing a first holographic image of said object with detector means;
- applying a force to said object;
- adjusting said detector means to compensate for displacement of said object;
- capturing a second holographic image of said object;
- electronically reconstructing said first holographic image;
- and
- comparing said second holographic image to said first holographic image.
A process for measuring strains in accordance with claim 16, wherein said optical fiber comprising said other continuous light point source which emits an adjustable light is wound around a piezoelectric phase shifter, said phase changes in said adjustable light being produced by dimensional changes in said piezoelectric phase shifter producing one of stretching and contracting of said optical fiber.
Dependencies are inferred from the claim text.