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181 results about "Gauge length" patented technology

The term ‘gauge length’ denotes the length of a specimen used for testing purposes. The latter is usually taken as the length between the grips for the test.

High temperature resistant spring-type device for measuring metallic material deformation

The invention relates to a high temperature resistant spring-type device for measuring metallic material deformation, which comprises high temperature resistant springs, an upper clamp splice, a lower clamp splice, extension rods, deformation sensors, and a high temperature furnace. The upper clamp splice and the lower clamp splice are both arranged in the high temperature furnace, and end portions thereof are provided with the high temperature resistant springs and are fixedly provided with the extension rods. Due to compacting forces of the high temperature resistant springs, in the process of the sample being extended longer and thinner by high temperature, edges of the upper clamp splice and the lower clamp splice are driven to move inwardly with even, and the sample is always clamped firmly. The lower ends of the extension rods extend from a lower opening of the high temperature furnace, and are connected with the deformation sensors at two symmetrical sides of the sample, such that a two-side measuring system is formed for measuring a deformation value of the sample. Compared with the prior art, the device, simple in structure and convenient in installation, can both measure the deformation values within a gauge length of common and special non-boss metallic material samples in a high temperature extension test, wherein the common non-boss metallic materials are wire materials, bar materials, tube materials, etc., while the special non-boss metallic materials are multi-ply type such as steel wire cables, etc.
Owner:TONGJI UNIV

Tunnel convergence deformation distribution fiber monitoring method and system thereof

InactiveCN102384725ARapidly converges on deformed dataObtain converged deformation data quicklyThermometers using physical/chemical changesUsing optical meansTime domainSEMI-CIRCLE
A tunnel convergence deformation distribution fiber monitoring method is disclosed. A setting method of a distributed fiber convergence deformation monitoring sensor is adopted. The method is characterized in that: a sensing fiber is arranged on a matrix sheet material surface which has a same shape with an inner-side curved surface of a shield tunnel concrete segment so as to form a distributed fiber convergence deformation sensor and two ends of the sensor are respectively fixed on the inner side of the concrete segment; a cross section is in shapes of a rectangle, a U shape, a semi-circle or an arc or a circular ring; the sensing fiber has two parallel paths; one path is tight buffer fiber, which is used to measure strain alonga radial direction of the sensor; the sensing fiber is arranged on the surface of the sheet material sensor; using Brillouin optical time domain analysis (BOTDA) method, through calibrating correlation between a sensor gauge length convergence value and sensing fiber strain variation, convergence state change information of the tunnel section can be converted and measurement of the tunnel section convergence value can be performed. By using the invention,monitoring and measuring precision of the convergence state of the any representative section of the tunnel is high.
Owner:NANJING UNIV

Method for determining modulus of elasticity of plastic concrete

InactiveCN102116716AAvoiding the Pitfalls of Experimental ErrorReflect deformabilityStrength propertiesPrismEngineering
The invention discloses a method for determining modulus of elasticity of plastic concrete. 3 150x150x300mm prism testing pieces are manufactured under industrial standards, the testing pieces to be measured are placed on a testing machine and starting reading is recorded, the testing machine is started, deformation values under various loads are recorded, and static compressive modulus of elasticity of the testing pieces are calculated in accordance with the following equation Ec = (P1/A) x (L/deltaL), wherein L is the full length of the testing pieces. The average value of the static compressive modulus of elasticity of the three testing pieces is regarded as the testing result. The method fills in the blank in the aspect of plastic concrete testing method, is characterized by adopting full gauge length for measuring the testing pieces, avoiding pre-pressing procedure and taking the slope of 40% secant as the elastic modulus value of the plastic concrete, and simultaneously eliminates 0.5MPa of stress and the calculation of stress items thereof from the calculation of the testing result, thereby overcoming the defect of large error in the prior method, achieving simpler and faster testing process and being advantageous for the popularization of the method.
Owner:SINOHYDRO BUREAU 14 CO LTD

Method for identifying bridge deflection based on long gauge length strain improved bending moment area method

The invention discloses a method for identifying bridge deflection based on a long gauge length strain improved bending moment area method. The method comprises the following steps of: S1, determininga bridge length L and a bridge cross section neutral axis height h; S2, continuously arranging m long-gauge-length strain sensors on the bridge in the length direction, and testing long-gauge-lengthstrain measured by each long-gauge-length strain sensor under the action of any load; S3, obtaining a function relationship between deflection and strain by adopting an improved bending moment area method; and S4, calculating the deflection of a point x at the moment t on the bridge according to the function relationship between the deflection and the strain. Based on an improved bending moment area method, the function relationship between the deflection and the strain can be deduced. Deflection distribution of any point on the structure along with time change and deflection distribution of the structure at any moment can be obtained through a formula in combination with the measured strain. The method is not affected by external loads, is suitable for static loads and dynamic loads, andis high in measurement precision, good in stability and convenient to use.
Owner:扬州市市政建设处 +1

Scale manufacturing technique of distributed high-precision self-monitoring FRP bar/rope based on optical fiber sensing

The invention discloses a scale manufacturing technique of a distributed high-precision self-monitoring FRP bar/rope based on optical fiber sensing. The technique mainly comprises the two procedures of: (1) preparation and packaging of a high-precision long gauge length optical fiber sensor, namely coating a resin coating layer with larger rigidity and thickness directly at the periphery of an optical fiber light-transmitting element, manufacturing non-slip optical fiber, then weaving/winding fiber at the periphery thereof in an unbonded manner and finally, coating an insulating gum with gauge length at the interval section of the surface to form a packaging product of long gauge length optical fiber; (2) using a long gauge length insulating method to manufacture the self-monitoring FRP bar/rope, namely leading the packaging product of long gauge length optical fiber into the scale production process of the FRP bar/rope, mainly comprising main techniques of control of optical fiber composite state, control of the shape of the self-monitoring FRP bar/rope and the like, and leading out the optical fiber in the insulating gum so as to be used for connecting other optical fiber by stripping the curved FRP. The product manufactured by the method can be cut randomly according to requirements and is a universal type product.
Owner:SOUTHEAST UNIV +2

Bidirectional long-gauge-length fiber grating strain sensor

InactiveCN103307995AAvoid multiple burialsFully protectedUsing optical meansFiberGrating
The invention discloses a bidirectional long-gauge-length fiber grating strain sensor. The bidirectional long-gauge-length fiber grating strain sensor comprises two measuring devices, wherein the two measuring devices are connected into a whole through an elbow and perpendicular to each other, each measuring device comprises a stress and deformation portion, a fiber grating sensor and a fiber grating adjusting instrument which is connected with the fiber grating sensor, each stress and deformation portion comprises two stainless steel disks and a stainless steel tube which is arranged between the stainless steel disks, the fiber grating sensors penetrate the stainless steel tubes, one ends of the fiber grating sensors are connected with the fiber grating adjusting instruments, the other ends of the fiber grating sensors are connected with each other through a connecting optical fiber which is arranged inside the elbow, and the fiber grating sensors are connected with inner walls of the stainless steel tubes through two bonding points. According to the bidirectional long-gauge-length fiber grating strain sensor, the two measuring devices are arranged, so that strain data in two directions can be read in one time, and sensors are prevented from being embedded repeatedly; and the stainless steel tubes are arranged, so that the sensors are fully protected, and the normal working of the sensors is prevented from being affected during foundation rolling compaction.
Owner:SHIJIAZHUANG TIEDAO UNIV +1

Intelligent photoelectric composite cable for monitoring local large deformation of structure and monitoring method

The invention discloses an intelligent photoelectric composite cable for monitoring local large deformation of a structure and a monitoring method. The intelligent photoelectric composite cable comprises distributed sensing devices capable of working together, wherein the distributed sensing devices are formed by compounding two sensing probes of an optical fiber and a coaxial cable employing silicone rubber as a cohering and filling medium and customizing a strain measurement gauge length in advance; various strains and temperature sensing probes are connected to an ROTOR demodulator, an FBG demodulator, a BOTDA/Rdemodulator and a CCFPI demodulator through transmission cables respectively; and strain data of a strain sensing array after temperature compensation correction is obtained, so that whole-process monitoring of the local large deformation of the structure is achieved. Aiming at the condition that an existing test method cannot easily track damage information of the local large deformation process of the structure, the bottleneck problem of combination of micro high precision and a macro large strain test is solved by the intelligent photoelectric composite cable; and a distributed optical fiber sensing technology and a distributed coaxial cable sensing technology are merged for the first time to construct an intelligent monitoring system.
Owner:DALIAN UNIV OF TECH

Multifunctional intelligent anchor pole and installation arrangement method thereof

The invention discloses a multi-functional intelligent anchor rod and its installation and layout method, which comprises non-fusion long gauge distance multi-grating sensor, optical fiber grating multi-point temperature compensation auxiliary sensor, epoxy resin or planting glue, armored optical cable and soft plastic Sleeve; the non-welded long-gauge-length multi-grating sensor and fiber-optic grating temperature-compensated auxiliary sensor are installed in the small groove opened along the longitudinal direction of the anchor rod, and are encapsulated by epoxy resin or planting glue; The grating sensor includes a plurality of long-gauge fiber grating sensing units connected in series. The long-gauge fiber grating sensing unit includes a sleeve, an optical fiber packaged in the sleeve, and a grating written on the optical fiber. The two ends of the optical fiber are respectively fixed on the Anchor section of casing. The invention can be used not only for anchorage and reinforcement in related projects such as civil engineering, tunnels, and mining, but also for monitoring the bearing capacity, stress-strain, and damage of anchor rods, and can be used for surrounding rock support and surrounding rock convergence deformation and stability monitoring.
Owner:SOUTHEAST UNIV

Displacement extension clamping device for measuring axial tensile deformation of steel cable at high temperature and using method of displacement extension clamping device

InactiveCN106018078ANo slippageEnsure synchronous displacementStrength propertiesEngineeringMechanical engineering
The invention discloses a displacement extension clamping device for measuring axial tensile deformation of a steel cable at high temperature and a using method of the displacement extension clamping device. The displacement extension clamping device for measuring the axial tensile deformation of the steel cable at high temperature comprises an upper clamp, a lower clamp and a high-temperature extensometer, wherein each of the upper clamp and the lower clamp comprises a U-shaped tube clamp, a V-shaped claw, bolts, a base and high-temperature nuts; U-shaped tube clamps sleeve a sample; two ends of each U-shaped tube clamp are respectively connected with the two corresponding bolts; each V-shaped claw is further arranged on the corresponding base; the U-shaped tube clamps and the V-shaped claws oppositely fasten to clamp the sample; the high-temperature nuts are tightened through the bolts, so that the sample, the U-shaped tube clamps and the V-shaped claws cannot slide relatively; the high-temperature extensometer is provided with two extension rods; a blade contact is arranged at the top end of each extension rod; the extension rods are adjusted so that the two blade contacts can be respectively inlaid in wedge-shaped grooves formed in the surfaces of the top ends of the two U-shaped tube clamps; high-temperature deformation in a gauge length section of the sample is transmitted to the extension rods; and test data are recorded by the high-temperature extensometer.
Owner:NANJING TECH UNIV

System and method for monitoring metal sample stress in high-temperature and high-pressure environment in real time

InactiveCN105092372AReal-time monitoring of strainOvercoming the conundrum of strainStrength propertiesData acquisitionEngineering
The invention provides a system and method for monitoring metal sample stress in a high-temperature and high-pressure environment in real time. The system comprises two connection assembly systems, two displacement sensing systems and a data acquisition system. The method includes the steps that when metal sample stress is monitored in real time and a metal sample bears axial force in the high-temperature and high-pressure environment in a high-pressure kettle, metal within the gauge length deforms in a stretch-out or draw-back mode, the deformation amount of the metal is transmitted to induction iron cores through the connection assembly systems fixed to the metal sample, inductance type extensometers can sense displacement of the induction iron cores and send out electric signals, a signal amplifier can amplify the electric signals, the data acquisition device acquires the amplified electric signals and calculates the displacement difference of the two connection assembly systems, and the metal sample stress is obtained by dividing the displacement difference by the original gauge length. The system and the method solve the problem that in the prior art, the stress can not be measured in real time in the high-temperature and high-pressure environment, high measurement accuracy is achieved, and the test requirements for mechanical and chemical interaction in various high-temperature and high-pressure environments can be met.
Owner:XIAN THERMAL POWER RES INST CO LTD
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