Floating-element shear-stress sensor
AssigneeUniversity of Florida Research Foundation, Inc.
InventorsStephen Brian Horowitz, Mark Sheplak, Toshikazu Nishida, Louis Nicholas Cattafesta, III
Life of this patent
Estimating the term…
Abstract
A shear-stress sensing system can include a floating element whose displacement can be detected through use of optical measurements. The system can utilize high temperature materials to deliver the optical signal to the structure to be measured, which can also utilize high temperature materials. In one embodiment, an intensity modulation or phase modulation of a reflected signal can be measured to determine the shear stress. In another embodiment, a Moire fringe pattern can be used to determine the shear stress.
Claims26
A shear-stress sensor system comprising:
- a floating element operably connected to a structure and displaceable with respect to the structure based on a shear stress induced in the structure;
- a light source for generating an optical signal;
- a first optical fiber in proximity to the floating element and positioned non-orthogonal to the floating element, the first optical fiber being operably connected to the light source for delivery of the optical signal to the floating element;
- and
- a second optical fiber in proximity to the floating element and positioned non-orthogonal to the floating element, wherein the second optical fiber receives a reflected signal based on the optical signal, the reflected signal being intensity modulated and proportional to a deflection of the floating element.
A shear-stress sensor system comprising:
- a floating element operably connected to a structure and displaceable with respect to the structure based on a shear stress induced in the structure;
- a light source for generating an optical signal;
- and
- an optical fiber in proximity to the floating element and positioned orthogonal to the floating element, the optical fiber being operably connected to the light source for delivery of the optical signal to the floating element, wherein the optical fiber receives a reflected signal based on the optical signal, the reflected signal being intensity modulated based on a spreading of the optical signal in free space after exiting the optical fiber, and the intensity modulation of the reflected signal being proportional to a deflection of the floating element.
A shear-stress sensor system comprising:
- a floating element operably connected to a structure and displaceable with respect to the structure based on a shear stress induced in the structure;
- a light source for generating an optical signal;
- an optical fiber in proximity to the floating element and being operably connected to the light source for delivery of the optical signal to the floating element, the optical fiber being a single mode fiber capable of coherent transmission of light;
- and
- an interferometer operably connected to the optical fiber, wherein the optical fiber receives a reflected signal based on the optical signal and delivers the reflected signal to the interferometer, the reflected signal being phase modulated, and the phase modulation of the reflected signal being proportional to a deflection of the floating element.
A system for determining a shear stress in a structure, the system comprising:
- a substrate support connected to the structure and having a first optical grating with a plurality of features defining a first spatial period;
- a floating element having a second optical grating with a plurality of features defining a second spatial period, the floating element being suspended over the first optical grating and flexibly connected to the substrate with compliant tethers or springs, wherein the first and second gratings are in an optical path with one another and form a Moiré fringe pattern when illuminated that relates to a shear-stress induced translation of the floating element;
- an imaging device;
- and
- an optical fiber bundle operably connected to the structure and having a distal end in proximity to the floating element for detecting and delivering the Moiré fringe pattern to the imaging device.
Dependencies are inferred from the claim text.