568 results about "Strain monitoring" patented technology

This invention relates to a strain monitor system for slope distributed fibers, which lays out several parallel special optical cables along the slope or at least lays out one close to the slope top and the corner separately, adheres symmetrically two fibers on the outer surface of a tilt testing tube to get the distortion of deep soil helped by the strain of the tube, the special optical cables are melted orderly to constitute a sensor circuit to be connected to BOTDR, which links with remote computers via local computer and internet to constitute distributed fiber strain monitor system and gets the distortion or displacement of the slope by integrating and summing the measured strain distribution further to evaluate and preset to the side slope.

The invention relates to a method and a system for monitoring and warning pipeline landslide depth displacement and a method for constructing the system. The monitoring is divided into three parts including landslide depth displacement monitoring, monitoring of thrust of landslide on a pipeline and pipeline strain monitoring, and comprises the steps of: inserting an inclinometer pipe (1) pasted with a fiber Bragg grating sensor into the landslide (13), penetrating all potential sliding surfaces (15), extending the inclinometer pipe to a drilling hole 3 to 5m deep under a bedrock surface, and measuring the maximum tension strain born by the inclinometer pipe (1); measuring the front thrust of the landslide (13) on the pipeline by using a packaged earth pressure cell fiber Bragg grating sensor (4) fixed on the pipeline (14); and uniformly arranging pipeline (14) monitoring sections on edges on two sides of the landslide and the pipeline (14) in the center of the landslide (13), and uniformly arranging three pipe strain fiber Bragg grating sensors (3) on each monitoring section to monitor the axial strain of the pipeline (14).

A system for monitoring strain as an indicator of biological conditions, such as spinal fusion, glucose levels, spinal loading, and heart rate. The system includes an inter-digitated capacitor sensor, and RF transmitter, and an associated antenna, all of which are microminiature or microscopic in size and can be implanted in a biological host such as a human or animal. An inductively coupled power supply is also employed to avoid the need for implantation of chemical batteries. Power is provided to the sensor and transmitter, and data is transmitted from the sensor, when an external receiving device, such as a handheld RF ID type receiver, is placed proximate the location of the implanted sensor, transmitter and inductively coupled power supply. The implanted sensor, transmitter and inductively coupled power supply can be left in place permanently or removed when desired.

The invention discloses a health monitoring system of a cable system in a cable structure on the basis of strain monitoring; a plurality of times of mechanical calculation is carried out on the basis of the reference model of the mechanical calculation of a structure, the times of the calculation is equal to the number of cables. Supposing that only one cable has unit damage during each calculation, the calculation result of each time constitutes a current strain calculation vector; a strain change vector is obtained by that each current strain calculation vector minus an initial strain vector; all the strain change vectors constitute a unit damage strain change matrix. According to the similar linear relation between the current strain vector (constituted by the current measured strain of all the given points) and the initial strain vector, the unit damage strain change matrix, an unit damage scalar and a current cable damage vector (constituted by current damage amount of all cables), the noninferior solution of the current cable damage vector can be figured out fast by utilizing the suitable algorithms of multi-objective optimization algorithm, etc., therefore, the position and the degree of damage of the damaged cable can be determined accurately.

A method for operating a marine seismic survey system includes deploying from a seismic vessel at least two lead-in cables each functionally coupled at one end thereof proximate a respective paravane. The lead-in cables have at least one spreader cable functionally coupled between the paravanes. Strain is measured at least one position along each lead in cable; and a length of each cable is adjusted such that the measured strains are substantially equal.

The invention discloses a temperature rise strain monitoring and alarming and fault analysis method for a composite submarine cable. The method comprises the following steps of: performing real-time temperature stress sensing on the composite submarine cable by utilizing abundant single mode fibers in a submarine cable, and evaluating the safety state of the composite submarine cable according to a power supply harmonic test parameter to realize real-time monitoring of the composite submarine cable. According to the method disclosed by the invention, real-time distributive safety monitoring and alarming can be performed on the composite submarine cable, and the safety sate of the composite submarine cable is judged according to the monitored power grid quality parameter, communication optical fiber excited brillouin reflection frequency offset and calibration data; and the fault analysis is performed on the composite submarine cable having a fault to find out the main reason of the fault.

The invention provides a method for manufacturing intelligent composite-material laminates used for monitoring structural longitudinal strain. In order to solve the technical problems that as fiber grating sensors are bonded to the surface of a structure through polyimide resin or epoxy resin commonly used in the prior engineering, optic fiber in service is easily destroyed; the optic fiber can get encapsulation protection but cause the concentration of surrounding stress/strain thereof if the optic fiber is directly embedded in a composite-material structure; and thermal residual stress produced in a material-curing process can cause chirp phenomena of fiber grating reflection spectrum to affect the measurement accuracy of grating strain, and the like, the invention provides the method for manufacturing intelligent composite-material laminates used for monitoring structural longitudinal strain. In the method, the fiber grating sensors are embedded in composite-material layers to replace resistance strain gauges commonly used in the field of monitoring structural health; by applying prestress to embedded fiber gratings, the influence of the curing residual stress of composite material on the fiber grating reflection spectrum is reduced so as to avoid the chirp phenomena; and the stability and repeatability of the sensors are improved. In addition, the composite material plays a good role in encapsulating and protecting bare fiber gratings, and meets engineering construction requirement on sensor sensitivity.

The invention provides a high temperature strain foil performance parameter tester and a test method thereof. The high temperature strain foil performance parameter tester is composed of a heating system, a heat preservation system, a temperature control system, a circulation system, a support system and a loading system. The tester and the test method of the invention can test technical parameters of the high temperature strain foil such as null shift, thermal output, thermal delay, mechanical delay, change of sensitivity coefficient with temperature, creep deformation of the high temperature strain foil, creep deformation of constant strength calibration beams made of measured target material and the like. The tester and the test method of the invention feature high test precision, good high temperature repeatability and reliable test results, thus providing data correction for long-term high temperature strain monitoring.

The invention relates to a monitoring technic of stratum motions before and after the coal bed mining, particularly relates to a 1:1 in-situ monitoring method of the large space range overlying rocks before and after the coal bed mining, and is specifically an in-situ monitoring method of the large space motions of the coal mine mining stratum. The problem that monitoring means for rock strata movements do not yet exist at present for large space ranges either within the nation or outside the nation is solved. The in-situ monitoring method comprehensively adopts a means based on the 'one form three places' method of the subsidence-overburden rock migration-underground mine pressure, and the in-situ monitoring method further adopts the geophysical prospecting methods of well upper and lower linkage observation, the drill hole television observation, the hole gap CT observation and the micro-seismic monitoring and the like, and the in-situ monitoring method also adopts the integration monitoring methods of the working face surrounding rock stress-strain monitoring and the like. The in-situ monitoring method creatively integrates various observation means, and through the reasonable arrangements, designs, observations and analyses of various monitoring means in large space ranges, mutual complements, comparisons and verifications between the various observation means are achieved, meanwhile each separate monitoring technic is innovated and promoted, and the in-situ precise measurement of the large space motions of the coal mine mining stratum is achieved.

The invention discloses a cast-in-place concrete major-diameter pipe pile body strain monitoring method based on BOTDA. The cast-in-place concrete major-diameter pipe pile body strain monitoring method is characterized in that a pair of vertical reinforcing steel bars are connected with arc-shaped reinforcing steel bars with arcs which are 1/4 of the circumference of a pipe pile to form carrier reinforcing steel bars. Grooves are formed in the carrier reinforcing steel bars, sensor fibers are embedded in the grooves, and the grooves are filled with epoxy resin. The pair of carrier reinforcing steel bars with optical fibers in an embedded mode are embedded in the cast-in-place concrete major-diameter pipe pile. Short pulsed light and continuous probe light are injected from the two ends of the sensor fibers with the BOTDA method, and strain information of points in the axial directions of the sensor fibers is obtained by measuring frequency changes of stimulated brillouin scattering light in the sensor fibers. The cast-in-place concrete major-diameter pipe pile body strain monitoring method has the advantages of being simple in construction wiring, resisting to interference, being high in accuracy and the like.

The invention discloses an elastic supporting device vibration strain monitoring method. A supporting body of an elastic supporting device comprises a bearing pedestal and a plurality of elastic cage strips which are distributed in the circumferential direction of the bearing pedestal, wherein one end of each elastic cage strip outwards extends in the radial direction of the supporting body to form an installation edge, and a gap is formed between the circumferential outer wall of the bearing pedestal and a machine box and filled with lubricating oil so as to form an extruded oil film damper. The method includes the steps that a strain gauge is attached to at least one elastic cage strip and connected to a vibration strain measuring instrument outside the machine box through a lead, and the vibration strain value of the strain gauge is detected through the vibration strain measuring instrument; whether the detected vibration strain value is larger than the preset vibration strain alarm threshold value or not is judged, and an alarm signal is generated if yes. By detecting the vibration strain value of the strain gauge, the vibration strain of the elastic supporting device is accurately detected, it is ensured that a journal of the bearing pedestal works within an extruded oil film linear area, an alarm is given once the vibration strain value exceeds the threshold value, and safe running performance of a rotor is improved.

The invention discloses a round solid concrete pile body strain monitoring method based on an FBG sensor. The method comprises the steps that smoothness processing is conducted on the surface of a round solid concrete pile body; optical fibers are laid in the axial direction of the surface of the processed pile body, and the FBG sensor connected to the optical fibers in series is bonded to the surface of the pile body; the optical fibers laid on the surface of the pile body are coated with epoxy resin; the ends of the optical fibers are connected into an FBG sensor data acquisition instrument; and the strain value of the pile body is measured. The round solid concrete pile body strain monitoring method based on the FBG sensor has the advantages of being simple in construction and wiring, high in success rate, low in cost, high in precision and the like.

The invention discloses a method for measuring and calculating circumferential strain of a rock sample by utilizing a distributed-type optical fiber grating sensing network. The method includes: arranging two sets of optical fiber grating sensors which are in series connection on a rubber sleeve coated on the outer surface of the rock sample at an interval along the peripheral direction and the axial direction of the rock sample in a staggered mesh form to form the optical fiber grating sensing network to measure and calculate local strain of each point in the circumferential direction of the rock sample; enabling each optical fiber grating sensor to be serially connected with one temperature compensation sensor to finally acquire circumferential strain of the rock sample and a circumferential deformation diagram of the rock sample at each transient time. Distributed mesh type sensor layout is utilized, so that accurate local strain monitoring of the circumferential surface of the rock sample can be realized while circumferential deformation diagram of the rock sample at a certain transient moment is acquired, knowing of deformation features of the rock sample at each stage of an experiment is facilitated, and circumferential strain features of the rock sample can be reflected more objectively.

An optical fiber concrete freezing-thawing expansion strain monitoring sensor comprises a single mode anti-bending optical fiber winding coil, a temperature compensation optical fiber grating, a concrete cylinder which is 5cm-8cm in diameter, a cement mortar protective layer, a steel pipe and an optical cable. The concrete cylinder is manufactured by concrete which has a same ratio as measured concrete materials, and the optical fiber winding coil is used for directly measuring circumferential deformation of the concrete cylinder caused by freezing-thawing. Circumferential deformation of the concrete cylinder in a whole measuring point can be monitored from a service period to the whole process that the protective layer is cracked and stripped after the interaction process of a plurality of freezing-thawing circulating periods is undergone, so that concrete freezing-thawing expansion strain is accurately monitored. An optical fiber sensor technology is adopted, so that durability of the sensor is greatly improved. The sensor manufactured through a packaging method is suitable for freezing-thawing expansion strain monitoring of bridges, dams and other concrete structures, and the optical fiber concrete freezing-thawing expansion strain monitoring sensor has the advantages of being simple in process, convenient to arrange, high in accuracy, long in service life and the like.

The embodiment of the invention provides a fiber Bragg grating strain sensor, the sensor comprises a diamond-shaped strain base and a fiber Bragg grating, wherein two ends of a grating region of the fiber Bragg grating are respectively fixed on one shaft of the diamond-shaped strain base; and the other shaft of the diamond-shaped strain base is respectively fixed on a measured basal body, and the diamond-shaped strain base can convert the deformation of the diamond-shaped strain base to the wave length change of the fiber Bragg grating. The fiber Bragg grating strain sensor can provide the fiber Bragg grating sensor which can carry out strain on-line monitoring under a large cryogenic project through the structure of the sensor, thereby effectively eliminating the impacts of electromagnetic interference under the complicated harsh environment, ensuring the reliability of monitoring data and improving the strain monitoring performance.

The invention discloses a dangerous and old building monitoring system based on the Beidou positioning technology. The dangerous and old building monitoring system comprises a, an inclination and settlement monitoring module which is used for extracting the inclination characteristic quantity of the monitored house building in real time; b, a crack monitoring module which is used for monitoring the crack width of the monitored house building in real time; c, a stress-strain monitoring module which is used for performing real-time stress-strain characteristic quantity monitoring on the monitored house building; d, a dynamic characteristic monitoring module which is used for monitoring the change of the dynamic characteristic after internal damage of the monitored house building; e, an information processing module which is used for receiving the monitoring data outputted by the inclination and settlement monitoring module, the crack monitoring module, the stress-strain monitoring moduleand the dynamic characteristic monitoring module; f, a BDS positioning system; g, an auxiliary monitoring module; h, a central processing module; i, an intelligent analysis cloud platform; and j, a client side module. The advantages are that safety warning of the dangerous and old building can be realized.

The invention discloses a high-sensitivity fiber Bragg grating strain sensor. The two ends of a tail fiber terminating fiber Bragg grating are fixed in a metal sheet structure central zone through binder. The two ends of the tail fiber terminating fiber Bragg grating are connected with a loose tube and armored cables in a sleeved mode at the same time. The armored cables penetrate through vertical circular holes in the two ends of a metal sheet structure. Meanwhile, two pressing blocks are connected with the metal sheet structure through screws, and the cables penetrating in the metal sheet structure are clamped. During mounting, the two pressing blocks and an object to be detected are bound or fixed in a clamping mode. The distance between the pressing blocks is longer than that between binder at the two ends of the fiber Bragg grating, so that strain measuring sensitivity is improved. By detecting the variation quantity of fiber Bragg grating reflected light wave length, the strain capacity of the object to be detected is determined. The high-sensitivity fiber Bragg grating strain sensor has the advantages of being high in sensitivity, high in detecting accuracy and high in reliability, anti-electromagnetic-interference performance and anti-thunderstrike performance are achieved, networking is easy, and the sensor is especially suitable for strain monitoring of a large structure.

This application relates to an apparatus and system for sensing strain on a portion of an implant positioned in a living being. In one aspect, the apparatus has at least one sensor assembly that can be mountable thereon a portion of the implant and that has a passive electrical resonant circuit that can be configured to be selectively electromagnetically coupled to an ex-vivo source of RF energy. Each sensor assembly, in response to the electromagnetic coupling, can be configured to generate an output signal characterized by a frequency that is dependent upon urged movement of a portion of the passive electrical resonant circuit and is indicative of strain applied thereon a portion of the respective sensor assembly.

The invention discloses a wireless communication technology-based bridge strain monitoring system and method. The system comprises a plurality of vibration wire type strain sensors, a plurality of vibration wire type reading gages, a receiver and a computer, wherein the vibration wire type strain sensors are arranged on the surface of a bridge bottom plate or web plate; the plurality of vibration wire type reading gages are connected with the plurality of vibration wire type strain sensors through wires in a one-to-one correspondence manner, and the receiver is connected with the computer through an interface circuit; each vibration wire type reading gage is connected with a first wireless communication module, the receiver is connected with a second wireless communication module, and the first wireless communication module and the second wireless communication module form a wireless sensor network. The bridge strain monitoring system is simple in structure, flexible and convenient to distribute and not limited by terrain environments, the defects of a cable laying mode are overcome, a great amount of manpower and material resources can be saved, the data is automatically collected, manual intervention is not required, not only is the real-time property of collection guaranteed, but also the long-time dynamic monitoring is easily realized.

The invention discloses a microstrip antenna RFID label-based array strain sensor. When the microstrip antenna RFID label-based array strain sensor is used as a novel detection technology of a passiveantenna and applied to draught fan blade strain detection, the defect of complexity of a traditional monitoring structure is overcome, the microstrip antenna RFID label-based array strain sensor is low in cost, the detection distance is extended, the interference to an environment is reduced, the detection range is expanded, and the microstrip antenna RFID label-based array strain sensor has important significance to health monitoring of a draught fan blade structure. The label sensor comprises a label antenna and a label chip and is characterized in that the label antenna comprises a metal radiation surface, a dielectric base layer and a metal grounding layer, wherein one end of the label is a radiation end, the other end of the label is a matching end, and structure strain monitoring isachieved by a relation between offset and strain of a label resonant frequency; since unique label information exists in each label chip, a reader can simultaneously read a plurality of label information; and a plurality of labels are buried in a draught fan blade and are arranged in an array way, large-area stress monitoring is achieved, and the function of the sensor is achieved.