Abstract:
A waveguide sensor according to an embodiment of the present invention includes: a substrate; a first underclad arranged on one side of the substrate; a first sensing core arranged on outer side of the first underclad and having a stripe pattern which extends in one direction; a first overclad arranged on outer side of the first sensing core; a second underclad arranged on another side of the substrate; a second sensing core arranged on outer side of the second underclad and having a stripe pattern which extends in a direction not parallel to the direction in which the first sensing core extends; and a second overclad arranged on outer side of the second sensing core. A first grooved part which extends in a direction not parallel to the direction in which the first sensing core extends is formed on the first overclad, so that the first grooved part and the first sensing core together form a first grating in a plane view. Furthermore, a second grooved part which extends in a direction not parallel to the direction in which the second sensing core extends is formed on the second overclad, so that the second grooved part and the second sensing core together form a second grating in a plane view.
Abstract:
A method of measuring strain in a test specimen comprises the steps of placing a pattern of marks on a surface of the test specimen, wherein the pattern of marks includes a plurality of target marks and a plurality of sets of coded marks, using the sets of coded marks to identify locations of at least two of the target marks, and using a change in distance between at least two of the marks to determine strain in the test specimen. An apparatus that performs the method is also provided.
Abstract:
A method of measuring strain in a test specimen comprises the steps of placing a pattern of marks on a surface of the test specimen, wherein the pattern of marks includes a plurality of target marks and a plurality of sets of coded marks, using the sets of coded marks to identify locations of at least two of the target marks, and using a change in distance between at least two of the marks to determine strain in the test specimen. An apparatus that performs the method is also provided.
Abstract:
The invention relates to core-shell particles comprising a shell which forms a matrix, and a core which is essentially solid and has an essentially monodisperse size distribution, the refractive index of the core material being different from that of the shell material. The invention especially relates to the use of said particles for producing sensors for detecting mechanical forces and sensors having an optical effect, essentially consisting of core-shell particles comprising a shell which forms a matrix and a core which is essentially solid and has an essentially monodisperse size distribution, the refractive index of the core material being different from that of the shell material. The inventive particles are characterised in that at least one contrast material is stored in the matrix.
Abstract:
An evaluation method for monitoring the consequences of an impact at low speed and little force on a structural composite material part covered with a film that changes color when under pressure and whose color intensity is directly related to the force of a received shock.
Abstract:
A pressure measurement method using a pressure measuring film in which a toner layer with a definite thickness is held between an adhesive layer formed on a first support and an inactive adhesive layer formed on a second support. Prior to applying the pressure to be measured to the measuring film, the inactive adhesive layer is activated to have an adhesive property. After pressure to be measured is applied to the film, the first support is removed and the applied pressure is determined based on the amount of toner attached to the second support. Using a toner having extremely small size, an extremely low pressure applied to an extremely small contact area can be measured. Also the pressure measuring film is not affected by use conditions (temperature, humidity). The inactive adhesive layer may be formed of a thermoplastic resin adhesive which can be activated by heating to become adhesive.
Abstract:
A film is placed between contacting surfaces in an assembly. The film has an optical property responsive to pressure. A compressive force is applied to the contacting surfaces to generate an initial pressure pattern. The film is removed from between the contacting surfaces. The optical property is sensed to derive a sensed initial pressure pattern. A stored setting controls the compressive force. The sensed initial pressure pattern is compared to a reference pressure pattern. The stored setting is updated to adjust the compressive force as a function of the comparing.
Abstract:
The invention relates to a tactile sensor capable of obtaining information for a plurality of degrees of freedom at each point on a surface by introducing multi-channel sensing that uses color or optical spectrum to an optical tactile sensor. An optical tactile sensor is provided with a tactile section and imaging means, the tactile section comprising a transparent elastic body and a plurality of groups of markers provided inside the elastic body, each marker group being made up of a number of colored markers, with markers making up different marker groups having different colors for each group, and behavior of the colored markers when an object touches the elastic body being photographed by the imaging means. Preferably, the marker groups have mutually different spatial arrangements.
Abstract:
The present invention is a fiber optic cable which uses pressure sensitive films or tactile films in order to detect areas on a fiber optic cable where excessive loads have been applied or experienced. In the present invention, a plurality of strips of tactile film or pressure sensitive film are inserted, at regular intervals, throughout the fiber optic cable structure in a fashion similar to that of swellable tape. The tactile film or pressure sensitive film used can be any color-changing stress sensor which is formed in the shape of a flat strip. The present invention uses strips of tactile or pressure sensitive film of different widths which are inserted periodically throughout the cable, both circumferentially and along the length of the cable. The films are located between the buffer tube(s) and the outer jacket of the cable or between the fibers and the outer jacket of the cable. This intermittent use decreases the overall cost and weight of the cable, over using a continuous length of tactile film. It is also desirable, in the present invention, to have the tactile or pressure sensitive film with corrugated folds along the width of the film. This corrugation provides a much higher sensitivity to loads experienced by the cables due to more nullaggressivenull deformation of the film during buckling.
Abstract:
A fiber optic sensor is also disclosed for measuring or detecting the prece of an environmental field condition such as under-water acoustic perturbations. The sensor includes a force transfer transducer, which is enclosed within a shell, with a pressure equalizer for equalizing the interior and exterior shell pressures. An optical fiber is coiled about the transducer. An optical detector detects stress or strain in the optical fiber, resulting from external perturbations. The sensor is able to operate at various depths or altitudes. Pressure equalization enables the isolation of dynamic external perturbations from other pressure variations. For this purpose, a pressure equalizing valve may be used to allow the equalization of slow changes in static pressures, and the detection of higher frequency perturbations which might emanate from a target source.