Abstract: A load detecting sensor includes a first member, a second member, and an optical fiber. The first member has a groove having a bottom portion and a column portion which defines the groove. The second member covers the groove of the first member so that a surrounded space is formed. The optical fiber is arranged in the surrounded space. At least one of the first member and the second member is made of an elastic body. The surrounded space is deformable when load is applied to at least one of the first and the second members. When load is applied to at least one of the first and the second members, the deformation of the optical fiber is caused following the deformation of the surrounded space. Hereby, the load detecting sensor, which can decrease the manufacturing cost and increase the detecting sensitivity by the optical fiber, can be obtained.

Abstract: A device for measuring electromechanical properties and microstructure of nano-materials under stress state comprises two bimetallic strips placed on an insulated metal ring plated with insulating paint, wherein the two bimetallic strips are placed in parallel or V-shaped to insulated metal ring on the same plane, one end of each bimetallic strip is fixed on the insulated metal ring, the other end of the bimetallic strip hangs inside of the insulated ring, the distance of two bimetallic strips were controlled within 0.002-1 mm. Also provided is a method for measuring electromechanical properties and microstructure of nano-materials under stress state.

Abstract: An integrated device for monitoring an electrically insulating part comprising an optic fiber in which at least one Bragg grating is formed, the electrically insulating part being made from a composite material with a thermosetting matrix, and the optic fiber comprising a mechanical protection sleeve made from polyimide material. An electrically insulating part or an electrically insulating enclosure in which the foregoing device is integrated. A method for manufacturing the foregoing device comprising positioning of a part of an optic fiber in which at least one Bragg grating is formed in a mold to form the electrically insulating part, and molding of the electrically insulating part.

Abstract: A method of monitoring strain on a helicopter rotor blade that has several structural components comprises locating at least three strain sensors 2a, 2b, 2c on one of the structural components of the rotor blade, the positions of the strain sensors defining a plane transverse to the longitudinal direction of the rotor blade and resolving strain signals from the three strain sensors into strain measurements in two orthogonal directions.

Abstract: The invention relates to an instrumented tubular device for transporting a pressurized fluid notably in the field of oil exploration and in that of the transport of gas or hydrocarbons. This device comprises a tube in which this fluid flows, with which are associated means for measuring the main deformations of this tube, and means for measuring the temperature of the fluid in the tube. This tube is equipped with measurement means integral with its surface and offset by at least one remote optical cable towards an electronic measurement system. These measurement means are means for assembling at least two non-parallel optical fibers which comprise at least three assemblies of at least two optical gages with Bragg gratings attached to at least three measurement locations and connected to the remote optical cable via optical fibers. At least one assembly further comprises a temperature gage.

Abstract: A system measures the strain of an object. The system includes a laser source for generating an output radiation, a strainable optical fiber having first and second facets, and means for calculating a measure of a strain of the optical fiber. The first facet is coupled to the laser source for receiving the output radiation and for transmitting therefrom a guided radiation over the optical fiber towards the second facet. The second facet is adapted to receive the guided radiation and to reflect a corresponding reflected radiation towards the first facet. The laser source is a self-mixing type adapted to receive at least part of the reflected radiation and to mix the output radiation with the received radiation. The calculating means calculate the measure of the strain of the optical fiber through the linear displacement of the second section measured by the self-mixing effect in the laser source.

Abstract: An image pickup device disposed in a predetermined position relative to a surface of a strained silicon wafer photographs the surface of the strained silicon wafer in a plurality of rotation angle positions on photographing conditions under which bright lines appearing on the surface of the strained silicon wafer can be photographed, in an environment where a light source device illuminates the surface of the strained silicon wafer which is rotating. A composite image in a predetermined angle position is generated from surface images of the strained silicon wafer in a plurality of rotation angle positions obtained by the image pickup device.

Abstract: The invention relates to coated optical fibers comprising soft primary coatings and to such primary coatings for protecting glass optical fibers having a sufficient high resistance against cavitation. In particular, the primary coatings have a cavitation strength at which a tenth cavitation appears (?10cav) of at least about 1.0 MPa as measured at a deformation rate of 0.20% min?1 and of at least about 1.4 times their storage modulus at 23° C. The coating preferably shows strain hardening in a relative Mooney plot, preferably has a strain energy release rate Go of about 20 J/m2 or more, and preferably has a low volumetric thermal expansion coefficient. The invention furthermore provides a method and apparatus for measuring the cavitation strength of a primary coating.

Abstract: A lifting member transmits all or part of the lifting force between a lifting appliance and a load to be lifted. The lifting member includes a proximal portion configured to be fixed to the lifting appliance; a distal portion designed to be connected to the load; a longitudinal section, extending from the proximal portion towards the distal portion, and capable of being elastically elongated under the action of part of the lifting force; a longitudinal channel extending from the proximal portion into the longitudinal section of the lifting member; a stress transducer, inserted into the longitudinal channel, and fixed to the side wall of the longitudinal channel; a link for transmitting optical fiber signals from the stress transducer to a device for receiving and analyzing optical fiber signals from the stress transducer.

Abstract: A method of determining the lift generated by a lift-generating member is presented. The lift-generating member being coupled to a component within the lift load path with the lift load path component experiencing strain as a result of the lift generated by the lift-generating member. The method involves the steps of coupling at least one strain measurement means to the lift load path component, obtaining strain measurements from the strain measurement means, and calculating the lift generated by the lift-generating member from strain measurements.

Abstract: A method includes rotating a rotor, measuring a rotor rotational time for the rotor to complete a revolution, determining a blade interval by dividing the rotor rotational time by a number of blades carried on the rotor, establishing an active hold-off time interval as a percentage of the blade interval time, directing a beam of light at the blades of the rotor using a laser, sensing light reflected from the blades, generating an output signal as a function of the sensed light, establishing a signal amplitude threshold, analyzing an amplitude of the output signal to trigger the active hold-off time interval when the amplitude reaches the signal amplitude threshold, and generating a blade arrival signal as a function of triggered active hold-off time intervals. The output signal is not analyzed within each active hold-off time interval.

Abstract: Methods and systems for measuring and gathering data relating to publication usage by participants in publication readership studies. Some methods and systems employ portable monitors carried by participants of the studies along with publications fitted with various devices, such as piezoelectric transducers, RFID tags and others devices and circuits.

Abstract: Structural member bend radius sensor apparatus 90 comprises three fibre Bragg grating (FBG) strain sensors 102 provided within three optical fibres 14, 16, 18. The optical fibres 14, 16, 18 and the FBGs 102 are embedded within a part-cylindrical shaped carrier member 92. The fibres 14, 16, 18 are provided at three spaced locations across the shaped carrier member 92 so that, in use, the three respective FBG strain sensors will be located at three different angular positions around the circumference of the structural member (pipe) 68. Structural member shape measurement apparatus 100 comprises four bend radius sensor apparatus 90 provided at four bend radius measurement positions along the pipe 68. The four bend radius sensor apparatus 90 shown share their optical fibres 14, 16, 18, and a single shaped carrier member 92. The shape measurement apparatus 100 further comprises FBG interrogation apparatus 104.

Abstract: A method of monitoring mechanical characteristics of helicopter rotor blades 1 comprises mounting at least one strain sensor 2 to at least one rotor blade 1 and measuring the mechanical load on the rotor blade as indicated by the strain sensor 2.

Abstract: A process and device for dynamic measurement of the axial deformation of a rotating hollow shaft (10), a glass fiber segment (16) of a fiber optic sensor (18) being attached securely to a section of the inside wall of the hollow shaft (10) extending in axial alignment with the shaft. A light signal produced by a light source (24) is injected into the glass fiber segment (16), and the light signal being detected by a detector (28) after passing through the glass fiber segment (16). Axial deformation of the section of the inside wall of the hollow shaft (10) is ascertained by determining axial deformation of the glass fiber segment (16) from the change of at least one parameter of the light signal that occurs when the light signal passes through the glass fiber segment (16).

Abstract: A load cell having an optical micro-resonator in a housing formed of high thermally conductive material. Upon application of a force to a surface of the housing, the micro-resonator is squeezed and changes in shape and refractive index, thereby changing the resonant frequency of the micro-resonator and causing a shift in the spectrum of wavelengths of light that is introduced to the micro-resonator. This shift in the spectrum of wavelengths is representative of the force applied to the housing of the load cell.

Abstract: In a system and method for adjusting a static torque on a slider in a head-gimbal assembly, a substantially rigid mass is placed on an air-bearing surface (ABS) of a slider. A static attitude of the slider is measured, and an adjustment location and intensity for a flexure to yield a zero slider static attitude are calculated. The flexure is adjusted based on the measurement and calculations.

Abstract: A method of monitoring the surface of a sample under test is provided and the method comprises the steps of: illuminating the surface with light (20) polarised in a first direction; viewing light reflected from the surface through a polarising filter (27) arranged at 90° to the first direction, wherein the surface of the sample under test is provided with a marked area where diffuse reflection of the incident polarised light will occur in order to improve the contrast between the marked area and the surface of the sample under text.

Abstract: An optical-encoded force sensor is disclosed. The optical-encoded force sensor includes a cantilever probe having a probe tip, a set of reflective phase gratings and multiple nano-photonic displacement sensors. The reflective phase gratings are mechanically coupled to the cantilever probe, and the nano-photonic displacement sensors are mechanically coupled to the reflective phase gratings. In response to a load being applied to the probe tip, the reflective phase gratings can be compressed such that a diffraction order of the reflective phase gratings changes according to the force of the applied load.

Abstract: Apparatus (10) for monitoring changes in the shape of a hollow structure (20) comprises a flexible elongate support (12), which includes several optical fibre strain sensors (14, 16, 18) each arranged to measure strain in the longitudinal direction of the support (12). The strain sensors (14, 16, 18) are spaced in a direction perpendicular to the longitudinal direction of the support and the support is adapted to bear against the inner surface of the hollow structure (20), such that changes in shape of the structure along the longitudinal direction result in generally corresponding changes in shape of the support.

Abstract: A detection system for measuring glass that has been placed under strain and the resulting stress lines in the glass has a light source of individual elements configured to create a light distribution. The light distribution has a discontinuity which enhances the viewing of a photoelastic effect in the glass. The light source creates a viewable optical interference (i.e., color changes) which results from stress lines in the glass.

Abstract: The load on an aircraft component, such as the load on a landing gear leg during braking, is measured with a contactless, all-weather displacement measuring system. The system includes a control unit a controllable microwave emitter of electromagnetic radiation and a microwave detector comprising a plurality of antennae. When the aircraft component is subjected to a load relative movement of the emitter and detector is caused. The detector generates in response to microwave radiation received from the focused beam of radiation emitted by the emitter a signal that is received by a signal processor of the control unit. The signal received by the control unit depends on the relative positions of the emitter and detector. The control unit is arranged to provide an output signal representative of the load sustained by the aircraft component. The system may be used to control braking in dependence on the output signal so as to maximize braking efficiency without overloading the landing gear leg.

Abstract: An energy beam is applied to an evaluation region of a sample, a phase distribution image of the energy beam transmitted to the sample in the evaluation region is obtained, and the obtained phase distribution image is analyzed, whereby a stress distribution in the evaluation region is measured. This measuring method measures a stress, based on a phase distribution image, whereby the stress can be measured irrespectively of a crystalline structure of an evaluation sample. A phase distribution image is used, whereby two-dimensional distribution images of the stress, density and refractive index can be obtained.

Abstract: This invention relates to a composite fibre including at least a first and second component, wherein at least one of the components is an optical fiber, and the components are intertwined.

Abstract: In one embodiment, a force sensor apparatus is provided including a tube portion having a plurality of radial ribs and at least one fiber optic strain gauge positioned over each rib of the plurality of radial ribs. The strain gauges are comprised of a negative thermo-optic coefficient optical fiber material in one embodiment. A proximal end of the tube portion is operably couplable to a shaft of a surgical instrument that is operably couplable to a manipulator arm of a robotic surgical system, and a distal end of the tube portion is proximally couplable to a wrist joint coupled to an end effector. In another embodiment, adjacent fiber optic strain gauges with differing thermal responses are used to solve simultaneous equations in strain and temperature to derive strain while rejecting thermal effects. In yet another embodiment, a thermal shunt shell is over an outer surface of the tube portion. An advantageous surgical instrument having improved temperature compensation is also provided.

Abstract: Strain waves of THz frequencies can coherently generate radiation when they propagate past an interface between materials with different piezoelectric coefficients. Such radiation is of detectable amplitude and contains sufficient information to determine the time-dependence of the strain wave with unprecedented subpicosecond, nearly atomic time and space resolution.

Abstract: A method is disclosed wherein a portion of a sensor part of an optical fiber sensor is embedded in an adhesive between two joined members, and peeling in an adhesive joint of the two members is detected on the basis of measuring optical characteristics from the optical fiber sensor when the optical fiber sensor is irradiated with light from a light source while one member is vibrated by vibration means. The method comprises the steps of determining the temperature of the two members during measurement on the basis of the optical characteristics from the sensor part exposed outside of the adhesive; determining, on the basis of the temperature determined during the measurement, the measurement range in which the optical characteristics from the optical fiber sensor are measured; and measuring the variation in the optical characteristics from the optical fiber sensor within the determined measurement range while the member is being vibrated by the vibration means.

Abstract: In one embodiment, a force sensor apparatus is provided including a tube portion having a plurality of radial ribs and a strain gauge positioned over each of the plurality of radial ribs, a proximal end of the tube portion that operably couples to a shaft of a surgical instrument that operably couples to a manipulator arm of a robotic surgical system, and a distal end of the tube portion that proximally couples to a wrist joint coupled to an end effector.

Abstract: A shear stress sensor for measuring the shear force of a fluid flowing along a wall. A floating member, flush with the wall, senses a shear force of the flowing fluid. The floating member is mounted by support means to a base element that is placed in the wall, so that the floating member is flush with the wall and a shear force, sensed by the floating member, is translated via the support means to a micro-resonator. The force acting on the micro-resonator changes the shape and the refractive index of the micro-resonator, thereby changing the resonant frequency of the micro-resonator and causing a shift in the spectrum of wavelengths of light that is introduced to the micro-resonator. This shift in the spectrum of wavelengths is representative of the shear force of the flowing fluid.

Abstract: The current invention relates to optical gages designed to measure strain on the surface of a test specimen. The gages of this invention is designed to be installed and used in a manner similar to conventional electronic foil strain gages, but to have the advantages of an all-optical gage. The gage of this invention is constructed to allow surface strain on the test specimen to be transferred to a length of optical fiber containing a fiber Bragg grating (FBG). As strain is applied to the fiber, the optical spectrum center wavelength reflected by the Bragg grating shifts in wavelength. This shift in wavelength can be converted directly to units of strain. The current invention provides a gage carrier design for use with fiber optic strain sensors comprising one or more FBGs which provide the benefits of a carrier for ease of handling and mounting without degrading gage performance.

Abstract: A modular fiber optic sensor that uses a light source to transmits light through at least one optical fiber to a sensor support. The sensor support is releasably attached to the optical fiber(s) allowing the use of both a single and multiple fibers. Diaphragms are exchangably attached to the sensor support allowing numerous diaphragm configurations to be attached to the sensor support. The different diaphragm configurations allow the sensor to detect a wide range of physical phenomena. A detection system is coupled to the optical fiber(s) that determines the change in light intensity which is reflected from the diaphragm's reflector.

Abstract: Provided is a stress history recording system for recording a stress history, which includes a light emitting means including a stress-stimulated luminescent material that emits light in response to a mechanical external force, and a recording means for recording a history of a photoreaction generated due to light emission from the light emitting means. This achieves a technology for recording a stress history by using the stress-stimulated luminescent material.

Abstract: A measuring device for detecting stresses of a bearing arrangement. The stresses are measured based on elastic changes in shape. The inventive measuring device includes a light source, which is directed onto a light passage, and a light sensor. The dimensions of a portion of the light that penetrates the light passage and impinges the light sensor can be modified by elastically changing the shape of the light passage.

Abstract: A system for displaying graphical information indicative of a plurality of material characteristics for a portion of a part under test. Energy is directed at the selected portion of the part under test. Resultant energy is detected from the selected portion of the part under test and data representative of each of a plurality of material characteristics for the portion of the part under test is obtained based, at least in part, upon the detected energy. A plurality of graphs is formed based upon the obtained data. Each of the graphs has information indicative of a separate one of the plurality of material characteristics. The plurality of graphs is displayed discrete from each other in a manner that facilitates substantially simultaneous visual comparisons between the information contained in each of the plurality of graphs.

Abstract: The invention is a method for obtaining the displacement of a flexible structure by using strain measurements obtained by stain sensors. By obtaining the displacement of structures in this manner, one may construct the deformed shape of the structure and display said deformed shape in real-time, enabling active control of the structure shape if desired.

Abstract: Provided are a stress analysis method and stress analysis equipment that enable a detailed stress measurement, by using both a photoelasticity measurement method and a stress measurement (mechanoluminescence measurement) which utilizes a mechanoluminescent substance to measure a stress state of an object. Physical quantities that are measurable include individual principal stress component and a principal stress direction. The photoelasticity measurement method alone cannot measure individual principal stress component values.

Abstract: The load on an aircraft component, such as the load on a landing gear leg during braking, is measured with a contactless, all-weather displacement measuring system. The system includes a control unit a controllable microwave emitter of electromagnetic radiation and a microwave detector comprising a plurality of antennae. When the aircraft component is subjected to a load relative movement of the emitter and detector is caused. The detector generates in response to microwave radiation received from the focused beam of radiation emitted by the emitter a signal that is received by a signal processor of the control unit. The signal received by the control unit depends on the relative positions of the emitter and detector. The control unit is arranged to provide an output signal representative of the load sustained by the aircraft component. The system may be used to control braking in dependence on the output signal so as to maximize braking efficiency without overloading the landing gear leg.

Abstract: In a method and system for evaluating sub-critical fatigue crack growth in a semiconductor device, a plurality of energy pulses generated by an energy source are repeatedly impinged onto the semiconductor device for a predefined time interval. The repeated impinging of the plurality of energy pulses induces a mechanical stress within the semiconductor device. The induced mechanical stress, maintained below a threshold and repeated for a predefined number of cycles, causes a formation of a sub-critical fatigue crack within the semiconductor device. A detector detects the presence of the sub-critical fatigue crack leading to a fatigue failure. A rapid determination of a pass or fail status for a fatigue test of the semiconductor device is made by comparing a total number of cycles to fatigue failure to a predefined benchmark.

Abstract: An inspection system for removably mounting to a platform movable in relation to a generally upright mast for inspection of the mast has a mounting support assembly removably fixable to the platform. The mounting support assembly for scanning the mast carries a detector device and collecting mast scanned information. A power supply is carried by one or more of the mounting support assembly or the detector device and is connected to the detector device. A communications device is carried by one or more of the mounting support assembly or the detector device and is connected to the detector device for receiving and relaying the collected mast scanned information.

Abstract: A device for generating a tensile force between a substrate and a coating, wherein the substrate has a thickness defined by a first side and a second side in a first axis, and the coating is applied to the first side of the substrate such that the coating and substrate are axially spaced along the first axis in intimate facing contact with each other to form a coating/substrate interface. The apparatus has a glass element disposed on the second side of the substrate and axially spaced along the first axis. The glass element is configured to propagate a stress wave to the coating/substrate interface to generate a tensile force between the substrate and the coating.

Abstract: A non-contacting strain measurement method and system employs a laser light source for irradiating a test piece to provide a spectral pattern in spaced relationship from the test piece. The pattern is viewed while the test piece is placed under tension by a plurality of video cameras. The CCD video cameras are coupled to signal processing circuits which calculate the Poisson ratio according to the formula: ? xx = - ? ? ? A x 2 ? L 0 ? tan ? ? ? 0 .

Abstract: A load detecting sensor includes a first member, a second member, and an optical fiber. The first member has a groove having a bottom portion and a column portion which defines the groove. The second member covers the groove of the first member so that a surrounded space is formed. The optical fiber is arranged in the surrounded space. At least one of the first member and the second member is made of an elastic body. The surrounded space is deformable when load is applied to at least one of the first and the second members. When load is applied to at least one of the first and the second members, the deformation of the optical fiber is caused following the deformation of the surrounded space. Hereby, the load detecting sensor, which can decrease the manufacturing cost and increase the detecting sensitivity by the optical fiber, can be obtained.

Abstract: The invention describes apparatuses and methods of monitoring fatigue, structural response, and operational limits in structural components. More particularly, the present invention relates to fatigue, response, and operational monitoring systems on steel catenary risers using optical fiber sensors. The sensors can be pre-installed on new risers, or post-installed sub-sea on existing risers, using a variety of methods.

Abstract: A system and method relating to the measuring of torque in a rotating shaft is provided. An optical torque sensing system comprises a rotating shaft, wherein a sleeve of photo-elastic material overlays a portion of the shaft. A light emitting component delivers light into the photo-elastic material, wherein the light delivered by the light emitting component is directed through the photo-elastic material along an axis of the rotating shaft. A capturing component captures the light that exits the photo-elastic material.

Abstract: The invention relates to a technique for reducing computation time for force vector calculation. A force vector reconstruction method that uses an optical tactile sensor, comprises a step for obtaining a marker image by taking an image of behavior of colored markers when an object contacts a contact surface of an elastic body, a step of obtaining information relating to the marker behavior from the marker image, the information being more than the number of force vectors to be obtained, and a step of obtaining force vectors as outputs by inputting information relating to the obtained marker behavior to a transfer function. The step of obtaining force vectors comprises calculating force vectors using only information relating to behavior of markers neighboring region A1 of a position A where it is desired to obtain force vectors.

Abstract: A method and apparatus are provided for detecting strain, stress, fatigue and incipient failure in materials. A detector (e.g., a photomultiplier tube) is used to detect photonic emissions from a material under test. Data based on the detected photonic emissions is displayed in real time so as to enable real time analysis of the data in determining strain, stress, fatigue and/or incipient failure.

Abstract: An optical sensor assembly comprising a plurality of optical fibre sensor coils optically coupled by optical fibre; and an elongate support element, on which said plurality of optical fibre sensor coils and optically coupling optical fibre are mounted is disclosed. The support element has an elastic limit such that when said support element is bent from the elongate axis, the optical fibre fracture limit is reached before the elastic limit is reached. An array of these optical sensor assemblies, the mandrel on which the sensing coils are mounted and their method of manufacture are also disclosed.

Abstract: A method and apparatus are provided for detecting strain, stress, fatigue and incipient failure in materials. A detector (e.g., a photomultiplier tube) is used to detect photonic emissions from a material under test. Data based on the detected photonic emissions is displayed in real time so as to enable real time analysis of the data in determining strain, stress, fatigue and/or incipient failure.

Abstract: A device for measuring adhesion strength between a first optical element and a second optical element includes a force gauge, a first magnet, and a second magnet. The second magnet is fixed to the force gauge. The first magnet and the second magnet are configured for magnetically attaching to opposite sides of the first optical element. An attractive force between the first magnet and the second magnet is greater than the adhesion strength between the first optical element and the second optical element.

Abstract: A substrate detection system is disclosed to include a conveyer that delivers the substrates, a sensor that detects the length of each substrate being delivered by the conveyer over the top side of the sensor, and a processor that compares the detection length value of each substrate detected by the sensor with a predetermined length value stored therein so as to immediately stops the conveyer when the detection length value of one substrate is unequal to the predetermined length value. In an alternate form, the time value in which each substrate passed over the sensor is used as a parameter for judgment.