360 results about "Stress sensing" patented technology

A mechanism to monitor an individual's level of stress in his or her home or workplace is provided. Unobtrusive physiologic stress senses are used in combination with a wireless link and a personal computer or other intelligent device to monitor the user's stress level. Based on a user profile and the user's baseline stress indicators, one or more stress-reducing activities are presented to the user. Additionally, if a user is in a stress-sensitive population, for example, persons with a pre-existing hypertension, the user may selectively enable additional alerts.

The invention relates to a cement-based composite material and a pressure sensor made of the same. The problems that the cement-based composite material has poor electrical resistivity and stress sensing ability because carbon fibers are not uniformly dispersed in a matrix, the pressure sensor is poor in stability and low in sensitivity and the like are solved. The graphene oxide / carbon fiber cement-based composite material is composed of functional components, cement, a dispersing agent, a water reducing agent, a defoaming agent, fine aggregates and other mineral admixtures, wherein the functional components include graphene oxide and carbon fibers, graphene oxide accounts for 0.01-5% of the total mass of a cementing material, and the carbon fibers account for 0.01-5% of the total mass of the cementing material. The graphene oxide / carbon fiber cement-based composite material disclosed by the invention has the advantages of high strength, good durability, few porosity defect, good compactness and the like; the pressure sensor has the advantages of stable initial electrical resistivity, high stress sensing ability, high sensitivity, good stability and the like; and the cement-based composite material is superior to a cement-based composite material which only takes the carbon fibers, graphene oxide, carbon black or steel slag and the like as a conductive phase.

A novel energy harvesting system and method utilizing a thermoelectric having a material exhibiting a large thermally induced strain (TIS) due to a phase transformation and a material exhibiting a stress induced electric field is introduced. A material that exhibits such a phase transformation exhibits a large increase in the coefficient of thermal expansion over an incremental temperature range (typically several degrees Kelvin). When such a material is arranged in a geometric configuration, such as, for a example, a laminate with a material that exhibits a stress induced electric field (e.g. a piezoelectric material) the thermally induced strain is converted to an electric field.

The invention discloses a sensing device of optical fiber distribution type temperature and stress and mainly comprises a light source module (1), a frequency discriminator module (2), and a thermo tank module (3), which are all connected with one another by polarization-preserving fiber. The invention is a direct detection method which is based on optical fiber Raman scattering used as a carrier wave of temperature information, brillouin scattering used as a carrier wave of stress, rayleigh scattering used for measuring relative frequency of a outgoing laser beam to a frequency discriminator and Fabry-Perot etalon used for discriminating frequency and distributing sensing temperature and stress. The invention has the advantages of simple structure, fine stability, avoidance of outgoing power of the light source during coherent detection, outgoing frequency of the light source. Instability of acoustic modulation or electro-optic modulation frequency is directly referred to measure errors and the direct detection technology of the frequency discrimination is not sensitive to frequency drift of the light source and fluctuation of signal intensity.

The invention discloses a detection method suitable for a sensing device of optical fiber distribution type temperature and stress. The sensing device of the optical fiber distribution type temperature and stress mainly comprises a light source module (1), a frequency discriminator module (2), and a thermo tank module (3), which are all connected with one another by polarization-preserving fiber. The detection method of the invention is a direct detection method which is based on optical fiber Raman scattering used as a carrier wave of temperature information, brillouin scattering used as a carrier wave of stress, rayleigh scattering used for measuring the relative frequency of a outgoing laser beam to the frequency discriminator and Fabry-Perot etalon used for discriminating frequency and distributing sensing temperature and stress. The invention has the advantages of simple structure, fine stability, avoidance of outgoing power of the light source during coherent detection, and outgoing frequency of the light source. Instability of acoustic modulation or electro-optic modulation frequency is directly referred to measure errors and the direct detection technology of frequency discrimination is not sensitive to the frequency drift of the light source and the fluctuation of signal intensity.

A stress sensing device senses a shear force and a pressing force. The stress sensing device includes a support body, a support film, first and second piezoelectric parts and an elastic layer. The support body has an opening defined by a pair of straight parts perpendicular to a sensing direction of the shear force and parallel to each other. The support film having flexibility closes off the opening. The first piezoelectric part is disposed over the support film and straddling an inside portion and an outside portion of the opening along at least one of the straight parts of the opening as seen in plan view. The second piezoelectric part is disposed to the inside portion of the opening and set apart from the first piezoelectric part as seen in the plan view. The elastic layer covers the first piezoelectric part, the second piezoelectric part, and the support film.

A novel energy harvesting system and method utilizing a thermoelectric having a material exhibiting a large thermally induced strain (TIS) due to a phase transformation and a material exhibiting a stress induced electric field is introduced. A material that exhibits such a phase transformation exhibits a large increase in the coefficient of thermal expansion over an incremental temperature range (typically several degrees Kelvin). When such a material is arranged in a geometric configuration, such as, for a example, a laminate with a material that exhibits a stress induced electric field (e.g. a piezoelectric material) the thermally induced strain is converted to an electric field.

Disclosed is an optical time domain reflectometer simultaneously sensing temperature and stress. The system is based on parallel detection of Rayleigh and Brillouin scattered light and includes devices such as a multi-wavelength laser source, a light-pulse modulator, a balance detector, a microwave amplifier, a high-speed data acquisition card, a coupler and a circulator and the like. In the optical time domain reflectometer, the frequency interval of wavelengths of the multi-wavelength laser source is arranged to be in a range of 9-12 GHz, which is equivalent to a frequency shift quantity of Brillouin scattered light in a fiber. A heterodyne coherent detection method is used to carry out parallel detection on Rayleigh and Brillouin scattered spectra and temperature and stress information is demodulated through a Landau-Placzek ratio (LPR) and Brillouin frequency shift distribution; and at the same time, coherent Rayleigh noises are reduced and superposition of the scattered spectra improves the signal-to-noise ratio of the scattered light. The optical time domain reflectometer is capable of realizing simultaneous temperature and stress sensing of a distributed fiber sensing system, improving the signal-to-noise ratio of the scattered light and improving the sensing precision and distance.

The invention relates to a graphene roll / carbon nanotube composite aerogel material, preparation and application thereof. The composite material is a three-dimensional network skeleton structure composed of graphene and carbon nanotubes together. The preparation method consists of: mixing a graphene oxide dispersion solution and a carbon nanotube dispersion solution, and performing ultrasonic treatment to obtain a mixed solution, then conducting quenching in liquid nitrogen, freeze drying and carbonization, thus obtaining the composite aerogel material. The composite aerogel material can be applied as a flexible electrode or stress sensing material. According to the invention, by means of a simple liquid nitrogen quenching method, two-dimensional graphene and one-dimensional carbon nanotubes are compounded, the advantages of the two materials are brought into full play, and while graphene rolls are formed, the porous structure composite aerogel with good compression resilience can be obtained.

The invention relates to a composite fiber with high conductivity, high elasticity and stress sensing performance, and a preparation method thereof, comprising 80-99 parts of high-elastic polymer fiber and 1-20 parts of conductive particles according to weight proportion; the preparation method comprises the steps as follows: a conducting medium bath with ultrasonic vibration is added based on the spinning and forming process of the fiber or during the post-processing of the fiber; and the conductive particles with the concentration of 1-30mg / mL is uniformly dispersed in water or organic solvent by the auxiliary function of the ultrasonic to form a nano-composite conductive fiber, with the dipping time of 5-600 seconds. The conductive composite fiber has the advantages of high conductivity, difficult falling of conductive compositions, durable conductive performance, high elastic performance, soft hand-feeling and the like; the preparation process is simple, the operation is convenient and the cost is low; the composite fiber can be produced continuously in large scale; and the stress sensing element is connected with a corresponding electronic element, thus being applicable to the real-time detection on the physiological status of the human body.

The invention discloses a detection method for soft rock multi-point ground stress by adopting sensing columns. According to the invention, the relative positions of a pair of three-dimensional pressure sensors are fixed by the sensing columns; one measuring point corresponds to one sensing column; in the sending process, relative movement between the two three-dimensional pressure sensors can be prevented; the diameter of each stress sensing column is only slightly smaller than that of a drill hole, so that only a small amount of grouting is required to enable the stress of the soft rock to be transferred to the sensors; the depth and the rotation angle of each sensor can be obtained accurately; the ground stress value at the testing point can be obtained accurately through numerical calculation of drill hole sectional mechanics, and the regional ground stress field can be obtained through inversion. The method can monitor the stress evolution process of multiple measuring points inside a surrounding rock, so that the research on ground stress of a coal mine and other deep soft rocks, as well as the stability of a surrounding rock, is facilitated.

The invention relates to an optical sensing system for detecting the transverse stress strain. Wherein, the laser outputs light to the polarize controller, to be coupled into the zero double refract or high refract photon crystal optical fiber which is marked with long-period grating and inside the forced unit to sense the external transverse stress; the spectrum detector connected to the output detects the transparent spectrum and outputs the detected information to the signal processing and displaying unit to attain the detect result of transverse stress; the output light of laser via the light circulator is coupled into the photon crystal optical fiber of Prague grating; the photon crystal optical fiber is inside the forced unit; the signal light reflected from the Prague grating via the light circulator is output to the spectrum detector to detect the reflect spectrum and output the detected information to the signal processing and displaying unit to attain the detect result of transverse stress.

The invention discloses a method for locating and installing a deep soft rock geostatic stress testing device. According to the method, a stress sensing column is manufactured, the stress sensing column is a cement concrete cylinder comprising two three-directional pressure boxes, and the center of each cubic pressure box is located on the medial axis of the cylinder; the front end of a push rod is connected with the stress sensing column, an angle testing device is installed, rotation angle and length of the stress sensing column are recorded when the push rod is pushed from a hole mouth to a tested point at the hole bottom, and accurate data necessary for stress resolving can be obtained. According to the method, no sharp protrusion exists at the front end or the side face of the stress sensing column, the hole wall will not collapse easily in the pushing process, relative positions of a pair of three-directional pressure sensors are fixed through the stress sensing column, the two three-directional pressure sensors will not move or rotate relatively in the pushing process, and the accuracy for calculating the geostatic stress of the tested point can be ensured.

The invention discloses a data demodulation method for polarization maintaining fiber stress sensing. The method comprises the following steps of: acquiring an interference signal by using a polarization maintaining fiber stress sensing test system to acquire photovoltage data; pre-processing the photovoltage data, averaging every n points to acquire new photovoltage data, and data volume; decomposing a photovoltage data signal into an intrinsic mode function (IMF) component and an allowance by an experimental mode method; finding out a basic component and identifying a small coupling point; reconstructing coupling intensity of a signal, and calculating the stress magnitude through intensity of each coupling point so as to realize the distributed detection of a system; and calculating indexes which can show the system test accuracy, such as a signal-to-noise ratio and the like. The method can effectively improve the signal-to-noise ratio of the polarization maintaining fiber stress sensing system, and improves the identification capacity of weak coupling points and the sensitivity of a coupling test. Under the environment of relatively low signal-to-noise ratio, microstress can be detected well.

This invention disclosed a method for monitoring the status of health by way of a belt which is integrated with stress sensing sensor and reaction output function. The user could follow its assistant to do breathing exercises, like belly breathing.

According to the present invention, by utilizing the characteristics of an electret material, an efficient contact-separation type friction nanometer generator is formed between a stress applying object and a sensing device contact layer, and is combined with the light emitting diodes skillfully, so that a self driven visual stress sensing device is constructed. Each light emitting diode corresponds to a friction nanometer generator unit, and when the external stress is applied to a contact layer of a sensor, a generated corresponding output signal drives the corresponding diode to emit light. The luminous intensity of the diodes is increased along with the increase of the applied stress, and the stress can be determined by analyzing the luminous intensity of the diodes, thereby realizing the visualization of the stress sensing. A stress visual device of the present invention has the characteristic of self-driven output, can analyze the external stress without needing an external power supply, and can be used to detect the spatial distribution of pressure.

A system for non-invasively monitoring a stress level of a subject is presented. A sensor is configured to monitor an attribute of the subject. A housing is configured to removably attach to the subject, the housing includes a processor in communication with the sensor, the processor is configured to retrieve data from the sensor, and use the data retrieved from the sensor to determine a stress level of the subject.

The invention discloses a bionic stress sensing structure and a formation method thereof. According to the bionic stress sensing structure, a conducting ink layer with strip-shaped parallel slit bands is formed on a paper substrate. The conducting ink layer is compact and rigid while the paper substrate is porous and soft. The formation method of the bionic stress sensing structure includes printing a layer of conducting ink on the paper substrate, wherein the conducting ink forms the dry conducting ink layer which is compact and rigid after drying up; and bending the paper substrate so as to make the dry conducting ink layer to break in the bending process. In this way, a plurality of slits are formed in the dry conducting ink layer and the slits form the slit band bionic structure. The dry conducting ink layer becomes the conducting ink layer with the strip-shaped slit bands, so that the bionic stress sensing structure is formed. When the paper substrate is stressed and deformation occurs, the contact degree of the slit walls of the strip-shaped slits of the slit band bionic structure changes, so that the resistance of the conducting ink layer varies. Therefore, the stress sensing function is achieved.

The invention discloses a curved surface display panel and a stress detecting and voltage adjusting method thereof, and relates to the technical field of display. According to the invention, the display area of the curved surface display panel is provided with a pixel area arranged in an array mode. The non-display area of the curved surface display panel is provided with a voltage adjusting unitand at least one set of stress sensing units. Each stress sensing unit comprises a plurality of pressure sensing sensors arranged in sequence. The connecting line of all the centers of the pressure sensing sensors is a curve in a first plane. The first plane intersects with the extending direction of the bending axis of the curved surface display panel. Each pressure sensing sensor is electricallyconnected with the voltage adjusting unit through a pressure sensing signal line. The voltage adjusting unit is used for receiving the pressure sensing detection signals of the pressure sensing sensors through the pressure sensing signal lines, and adjusting the voltage of at least one part of the pixel area according to the pressure sensing detection signals. Therefore, the voltage of a sub-pixel area can be adjusted according to the pressure sensing signals. As a result, the display brightness of the curved surface display panel in a pure-color display state is uniform, and the non-uniformbrightness phenomenon is avoided.

A sensor is provided for sensing a value of a physical parameter characteristic of the sensor's environment. The sensor is implemented in semiconductor technology. A behavior of the sensor's electronic circuitry is affected by stress. The stress is induced by a film covering the circuitry or only part thereof. The stress is caused by the film's material, whose dimensions depend on a value of the parameter. This dependence is different from the 5 dependence of the circuitry's substrate on the same parameter.

The invention provides a preparation method of a capacitive stress sensing intelligent fabric. Conductive yarns serve as electrodes of a capacitive sensor and are obtained by means of direct preparation, coating, coping and the like, insulating elastomers serves as dielectric materials coating the conductive yarns, the insulated conductive yarns alternately penetrate common yarns by the aid of interwoven overlapped structures among fabric yarns, a fabric sensing array is formed by common manufacturing technology, and the preparation method can be widely applied to stress monitoring and the like of intelligent garments, intelligent homes, touch screens, electronic skins and three-dimensional fabric composite materials.

The invention discloses a method and system for improving sensing performance of a long-distance Brillouin optical time domain analysis system. On the basis of the existing long-distance Brillouin optical time domain analysis system which uses a first-order Raman amplification technique, a pair of optical fiber gratings with peak reflectivity being larger than 80 percent and consistent central reflection wavelength are fused on the two sides of sensing optical fibers to form a long-distance laser resonant cavity. Laser generated by the laser resonant cavity is used as a second-order Raman pump and a first-order Raman pump to simultaneously take an effect of amplifying sensing signals. Compared with a Brillouin sensing system which is based on the first-order Raman amplification, under the conditions of the same pump power, the method and the system provided by the invention have the advantages that higher grains can be obtained and the pump efficiency is improved; the sensing signals are distributed more smoothly along the optical fibers; when the system is used for long-distance temperature / stress sensing, the spatial resolution, the measurement accuracy and the sensitivity of the monitoring system can be greatly improved; and the sensing performance is obviously improved at a low cost without increasing an additional second-order pump light source.

Provided is a discontinuous liquid level sensor based on the optical fiber bragg grating technology. The discontinuous liquid level sensor comprises a broadband light source, a 3dB optical fiber coupler, an FBG sensing array, a wavelength demodulation module and a micro-control unit. Light output by the broadband light source passes through a temperature reference optical grating and a stress sensing optical grating which are stuck to a cantilever beam structure in the FBG sensing array in sequence through the 3dB optical fiber coupler, and the packaging material of a sensing probe, the floater material and the optical grating sticking material all adopt carbon fiber; the liquid level change can change the acting force of a magnet on a floater to sheet iron on a carbon fiber plate, the carbon fiber plate is made to be deformed, the reflection wavelength of the sensing optical grating is changed, reflected light is input into the wavelength demodulation module through the 3dB optical fiber coupler, and demodulation of the reflection wavelength is completed; a signal is transmitted to the micro-control unit with a temperature-stress compensation algorithm for data processing. The discontinuous liquid level sensor is simple and reliable in structure, high in detection precision and sensitivity and capable of being applied to severe environments such as high temperature and high corrosion and achieving discontinuous detection of liquid levels of different heights.

The invention relates to a distributed optical fiber monitoring calibration and test device for soil deformation. The device comprises a calibration and test main box, stress sensing optical fibers, an optical fiber demodulation instrument and a digital image acquisition and analysis device; the front face and rear face of the test main box are transparent rigid plates, and the test main box is filled with soil which is compacted in a layered mode; the stress sensing optical fibers are laid in soil in the horizontal direction and / or vertical direction segment by segment; the optical fiber demodulation instrument is connected with the stress sensing optical fibers and acquires stress data in the soil; the digital image acquisition and analysis device is used for measuring displacement and stress of soil in contact with the front transparent rigid plate and the rear transparent rigid plate. By means of the distributed optical fiber monitoring calibration and test method and device, distributed optical fiber monitoring readings for soil deformation can be calibrated, the interaction and deformation coupling between the soil and the optical fibers are researched, and the spatial-temporal evolutional law of stress in the soil under different working conditions such as loading, unloading, digging and seepage is obtained.

The soil stress is composed of shell, stress-sensing module (SSM), and output cable. An elastic body capable of sensing stress is fixed at front end of shell of sensor. A clamped sidestep with structure of hole is formed inside the shell of sensor. Being fixed at end face of the clamped side step, SSM is silicon piezoresistance type module with structure of Wheatstone bridge. Fluid pressure medium for propagation is filled in a cavity formed between the end face of the clamped sidestep and the elastic body. Through an adapter plate, a lead out cable, a signal rectification circuit, the intraconnection of SSM is connected to the external output cable. Introducing mature silicon piezoresistance type sensing element to mechanics research area of soil stress, the invention fabricates piezoresistance type stress sensor. Features are: volume-produce by IC technique, good consistency and low frequency characteristic, simple signal process, and miniaturization.

The invention relates a fiber bragg grating high-temperature stress testing device applied to a structural heat test radiation heat environment and a mounting method of the fiber bragg grating high-temperature stress testing device. The device comprises a stress sensing optical fiber (3) which is equipped with a fiber bragg grating (5), two 8-shaped quartz tubes (2) and a temperature reference optical fiber (4), wherein the temperature reference optical fiber (4) is the same as the stress sensing optical fiber (3); the stress sensing optical fiber (3) and the temperature reference optical fiber (4) respectively pass through the two 8-shaped quartz tubes (2) to be parallel; the stress sensing optical fiber (3) is integrally fixed to the two 8-shaped quartz tubes (2) through fixing materials (6); the temperature reference optical fiber (4) is only integrally fixed to one 8-shaped quartz tube (2), and the other end of the temperature reference optical fiber (4) is suspended. With the adoption of the device, the temperature of degeneration of the fiber bragg grating at high temperature is solved; the device is applicable to the heat test environment at the temperature close to 1000 DEG C and achieves the high-temperature stress measurement of a composite material structural part.

The invention discloses a distributed optical fiber temperature and stress sensing device, and belongs to the technical field of optical fiber sensing. The device comprises a pulse laser and the like. The pulse laser is connected with an optical switch and a relay. A semiconductor laser is sequentially connected with an optical isolator A and an optical coupler, the optical coupler is sequentially connected with an acoustic optical modulator, an erbium-doped fiber amplifier and a scrambler, the scrambler is connected with the optical switch, and the optical switch is connected with a circulator A. The other output of the optical coupler is sequentially connected with a polarization controller, an electro-optical modulator and an optical isolator B, and then is connected with the circulator A through sensor fibers. A signal generator is sequentially connected to the acoustic optical modulator, the optical switch, a data collection card, a microwave source and a relay. The microwave source is connected with the electro-optical modulator. The circulator A is connected with the circulator B which is sequentially connected with a fiber Bragg grating, a Raman filter and a photoelectric detector A, and the photoelectric detector A is connected with the data collection card. The circulator B is sequentially connected with a photoelectric detector B and the data collection card. The distributed optical fiber temperature and stress sensing device can achieve simultaneous measurement on temperature and stress in a long-distance and distributed mode.

An exemplary multi-touch input device includes a stress sensing plate, a first polarizer, a infrared light module, a second polarizer, an infrared camera module, and a processor. The stress sensing plate has a touching surface, an internal stress is generated when an object touches the tress sensing plate. The infrared light source module is configured for emitting infrared light to the first polarizer. The first polarizer is disposed between the stress sensing plate and the infrared light source. The infrared camera module is configured for capturing the image corresponding to the infrared light outputting from the stress sensing plate through the second polarizer. The processor is to receive the infrared image from the infrared camera module and obtain the position or a trace the stress sensing plate be touched accordingly.

A method for realizing horizontal stress sense based on double mode photon crystal optical fiber includes coupling output light of laser into zero double refraction or high double refraction and double mode photon crystal optical fiber by horizontal dislocation mode after said output light passes through polarization controller, setting double mode photon crystal optical fiber in force receiving unit for sensing horizontal stress exerted from outside, utilizing far field light spot to detect space light field formed by double mode interference for obtaining detection result of horizontal stress. The system for realizing said method is also disclosed.