69 results about "Lateral strain" patented technology

A varifocal optical system includes a substantially circular membrane deposited on a substrate, and a ring-shaped PZT thin film deposited on the outer portion of the circular membrane. The membrane may be a MEMS-micromachined membrane, made of thermal oxide, polysilicon, ZrO2 and SiO2. The membrane is initially in a buckled state, and may function as a mirror or a lens. Application of an electric voltage between an inner and outer electrode on the piezoelectric thin film induces a lateral strain on the PZT thin film, thereby altering the curvature of the membrane, and thus its focal length. Focal length tuning speeds as high as 1 MHz have been demonstrated. Tuning ranges of several hundred microns have been attained. The varifocal optical system can be used in many applications that require rapid focal length tuning, such as optical switching, scanning confocal microscopy, and vibration compensation in optical storage disks.

The invention discloses a method for establishing a rock material ageing and elastic-plastic mechanics constitutive model. The method includes the steps that the triaxial short-long term test result of rock is used as the basis first, and the volumetric strains of a rock test piece under different test conditions are calculated; by drawing a stress-axial and lateral strain relation curve and a stress-volumetric strain relation curve, the yield criterion, the non-associated flow rule and the hardening criterion of the rock are determined, and an elastic-plastic mechanics model is established; then by combining material micro and fine damage attenuation ageing evolution dynamic equilibrium, the micro and fine ageing damage rule of the rock is determined, the model is popularized, a relation matrix of strain increment and stress increment at the ageing-elasticoplastic deformation stage is established, and accordingly the rock material ageing and elastic-plastic mechanics constitutive model is obtained. According to the model, the mechanics significance is definite, the expression is unique, the number of parameters is small and can be obtained based on the test results, hence, solving uniqueness and accuracy are guaranteed, and wide applicability and expansibility are achieved.

Ultrasonic strain measurements, which characterize the structure of tissue, may be obtained by combining multiple echo signals acquired at different compressions and at different angles. Such angular compounding may improve the quality of the elastic signal and provide at one time both an axial and lateral strain measurement.

The invention discloses a method of establishing an elastic-plastic mechanical constitutive model made of a rock material. The method comprises the following steps: measuring and recording variation values of axial and lateral strains of a rock specimen along with the stress, and calculating a volumetric strain of the rock specimen; drawing a stress-axial / lateral strain relation curve according to recorded full-course axial and lateral strain changes of the rock specimen, and respectively determining a yield failure rule and a hardening rule of the rock material of the specimen; drawing a stress-volumetric strain relation curve according to the calculated volumetric strain of the rock specimen to determine a non-relevant flow rule of the rock material of the specimen; determining the constitutive model by using a thermodynamic elastic-plastic theory in combination with the stress-strain curve, peak stress, yield initial stress and boundary strength of rock. The method disclosed by the invention comprehensively considers the yield rule, the non-relevant flow rule and the hardening rule of the rock material, favorably reflects the elastic-plastic mechanical behavior of the rock material and ensures the uniqueness and the accuracy of the constitutive model.

During triaxial compression test, a soil specimen experiences reduction of its height with simultaneous increase in its diameter. For calculation of new cross-sectional area, it is always assumed that the specimen deforms as a cylinder with uniform increase in diameter through its height. This condition is seldom or never met in actual soil specimens, because specimen undergoes non-uniform increase in diameter through its height and very often with localized bulging in specimen affecting the accuracy of calculation of magnitude of deviator stress at any instant of time during the test. Non-uniform increase in diameter through its height with often localized bulging affects the real strength and volume change characteristics, and how much this effect of non-uniform lateral increase in diameter changes these properties remains unknown. The expandable jacket wrapped around the soil specimen for performing the triaxial compression test included in this invention, shall maintain uniform diameter of soil specimen through its height and shall provide accurate prediction of deviator stress, volume change characteristics and strength of soil specimen. The calibration device for calibration of expandable jacket shall provide the magnitude of correction to be made in deviator stress at various levels of axial and lateral strains.

The invention relates to a strain type lateral expansion force testing device and a measuring method. The strain type lateral expansion force testing device comprises a measuring device, a data collecting device and a loading device. The measuring method comprises the following steps of performing water soaking expansion testing on specimens with same initial wet density states under non-load andnon-lateral strain conditions, and obtaining the expansion limit water content and corresponding dry density of the specimens with same initial wet density states under the condition of stable expansion; performing gradual loading type cementing testing on the specimens with same initial wet density states under the conditions of expansion limit water content and corresponding dry density, measuring the lateral pressure coefficient K0 at different dry densities, and stripping the lateral expansion force from the lateral resultant force. The strain type lateral expansion force testing device and the measuring method have the advantages that the testing method and the device are simple, the operation is convenient, the structure is reasonable, and the manufacturing cost is economical; the problem of stability of expanded soil edge slope after wetting expansion in the long-time expected precise evaluation process of the field is solved, the important design parameters are provided for thedesign of engineering structures and wall back buffer layers in the expanded soil area, and the device and the method are suitable for being popularized and applied in engineering.

The invention discloses a planar and lateral strain controlled triaxial apparatus. The triaxial apparatus can perform a lateral unloading test or a lateral confined stress relaxation test for a soil sample under a planar strain condition and acquire precise test data. A trolley of the triaxial apparatus comprises a bottom plate and first and second lateral plates which are parallel with each other and vertical to the bottom plate. The trolley is in rolling connection with a chassis; a first lateral plug, a second lateral plug and a lateral baffle are in rolling connection with the chassis of the trolley respectively and form a soil sample accommodating chamber together with the second lateral plate; a first pressure sensor is contacted with the outer side face of the first lateral plug; two ends of a first rotary screw are contacted with the second lateral plug and a first dial indicator respectively; a second pressure sensor is connected with the later baffle and is contacted with the first later plate; a cover plate is arranged on the top of the soil sample accommodating chamber; and a second dial indicator is contacted with the upper side face of the cover plate.

The invention discloses a method for determining an initiation stress index of damaged rock. The method comprises the following steps of firstly, carrying out triaxial compression test on the damagedrock, and recording corresponding test data; secondly, marking a point corresponding to an axial stress-lateral strain curve as a point N according to a damage stress index of the rock; thirdly, determining an initial point of the lateral strain according to a point of inflection of the axial stress-lateral strain curve, and marking as a point M; and finally, connecting the point N and the point Min the axial stress-lateral strain curve to obtain a reference line NM, and obtaining a lateral strain difference value by computing a difference value between the actually measured lateral strain and the reference line, wherein the maximum value of the lateral strain difference value is the initiation stress of the rock. According to the method, an initial fracture section of the lateral strainof the damaged rock at the microstructure of the initial stage is removed, and the accuracy of determining the crack initiation of a new crack in the damaged rock corresponding to the initiation stress is ensured; according to the method, the influence of human factors can be removed, the method has strong objectivity and is also easy to program and realize batch work.

The invention discloses a test piece dynamic lateral strain measuring device and method based on an SHPB test system, and belongs to the field of dynamic mechanical property testing of brittle materials such as coal rock by adopting the SHPB test system. The device comprises a fixing system, an oil pressure system and a data acquisition system; the fixing system is used for fixing the whole deviceon an SHPB test bed and adjusting the height of the device; the oil pressure system is used for applying required confining pressure to the test piece and converting a volume change signal of the test piece into an oil pressure change signal; the data acquisition system is used for capturing signals of oil pressure changes and obtaining a time-history change curve of lateral strain. The confiningpressure is applied to the test piece by utilizing the oil pressure system, comprehensive confining pressure loading of the test piece is simulated, and the comprehensive confining pressure loading and axial acting force caused by the split Hopkinson pressure bar device act together, so that simulation of a complex stress state of the test piece is realized; the relation between oil pressure andlateral strain is obtained through signals of oil pressure changes caused by the lateral strain so as to calculate the lateral strain.

The invention relates to a method of testing Poisson's ratio of concrete. The method includes: performing testing by pressurizing in static elastic modulus test, selecting a concrete specimen of specified size, selecting a specified test area on the concrete specimen and a test scheme, placing transverse strain gauges at the centers of two opposing sides of the concrete specimen, placing longitudinal strain gauges at positions, determined distances away from the upper and lower end faces, on two longitudinal sides of the concrete specimen, precisely measuring and recording transverse deformation and longitudinal deformation, and calculating the Poisson's ratio of the concrete through the transverse deformation, the longitudinal transformation and a conversion coefficient. The method has the advantages that measuring is precise and fast, testing cost is lowered and repeatability is good.

The invention discloses a fatigue test method of a rubber bushing, comprising the following steps: (a) acquiring vertical and lateral strain road spectrums and a displacement road spectrum of vertical jump of the rubber bushing in an actual road; (b) converting the vertical and lateral strain road spectrum to be a power value target signal and converting the displacement road spectrum of vertical jump to be displacement target signal; (c) performing iterative operation on the power value target signal and displacement target signal respectively to obtain a power value drive signal and a displacement drive signal; (d) applying the power value drive signal to the vertical and lateral directions of the rubber bushing respectively by a hydraulic servo mechanism, and vertically applying the displacement drive signal to the rubber bushing. The invention further discloses a matched fixture, by utilizing the method and the fixture, the problems that the difference between a test result and an actual use result of an existing rubber bushing table test is great and the table test is inexact are solved; the method and fixture is widely applicable in the field of rubber bushing tests.

The invention discloses a method of noninvasive high-precision vessel wall elastography. The method comprises the following steps: acquiring the radio-frequency data or video data of B-mode ultrasonic imaging of a vessel wall longitudinal section; making an off-line analysis on the acquired radio-frequency data or video data to obtain the displacement field of each frame of radio-frequency data or video data; filtering the displacement fields of the radio-frequency data or video data with an FIR two-dimensional difference filter to obtaining strain components on the longitudinal section, including a strain component Epsilonxx in the axial direction of a ultrasonic emission beam, a lateral strain component Epsilonzz and a shearing strain component Epsilonxz; giving a Von Mises strain projection parameter ZetaVM-longiProj and a calculation formula thereof, and imaging the Von Mises strain projection parameter ZetaVM-longiProj to achieve noninvasive high-precision vessel wall elastography. Precise and quantitative vessel wall elastography can be achieved through the method, and the result is superior to those of the conventional other vessel wall strain imaging methods.

A method for achieving uniaxial strain on originally biaxial-strained thin films after uniaxial strain relaxation induced by ion implantation is provided. The biaxial-strained thin film receives ion implantation after being covered by a patterned implant block structure. The strain in the uncovered region is relaxed by ion implantation, which induces the lateral strain relaxation in the covered region. When the implant block structure is narrow (dimension is comparable to the film thickness), the original biaxial strain will relax uniaxially in the lateral direction.

A force transducer for measuring compression and / or tension forces includes a rod-shaped deformation body and at least four strain transducers applied on the deformation body and configured for measuring longitudinal and transverse strains thereof. Front and rear elongate recesses are provided on the front and rear sides of the deformation body in the area of an intersection between a central longitudinal axis and a central transverse axis of the deformation body. Left and right upper indentations and left and right lower indentations are provided on the deformation body respectively at the four quadrants bounded by the axes. A ratio of a cross-section on a center plane extending orthogonally to the central longitudinal axis and including the central transverse axis, to a sum of first and second partial regions of the cross-section, is from 1.56 to 2.15.

The invention discloses a three-directional shearing model box device. The device comprises a steel plate and multiple framework layers mounted above the steel plate. The framework layers comprise multiple layers of frameworks, rubber dies arranged on the inner sides of the frameworks in a riveting manner, supporting units mounted between the framework layers, and columns mounted on the periphery of the steel plate. The frameworks are made of light aluminum alloy materials. The frameworks are parallelly arranged at equal vertical intervals. The columns are arranged on the periphery of a shearing model box at equal intervals, so that the shearing model box can freely move in three directions when inputting three-directional seismic excitation, and ultra-displacement, jumping and shedding phenomena during a test of the shearing model box can be avoided. The frameworks are made of aluminum alloy H-section steel, so that the weight of the shearing model box is reduced, and the influence on the whole model by the framework weight can be reduced. The aluminum alloy H-section steel frameworks have enough rigidity, so that the model soil is zero in lateral strain in the horizontal direction, and the aluminum alloy H-section steel frameworks can maintain original states after the seismic motion excitation.

A system for relieving lateral stress on rods within a wellbore. A flexible sucker rod coupling has a top connecting member threadedly attached to a ball shank housing. The ball shank housing houses in a ball and socket fashion, a ball shank which extends out of the ball shank housing, defining a swivel gap to allow swivel movement. The ball shank is threadedly attached to a lower connection member. Both ends of the coupling threadedly attaches to an adjacent sucker rod within the wellbore. The ball shank is secured to the ball shank housing to ensure that the ball shank and the ball shank housing rotate together.

The invention discloses medium strain rate test equipment and method with axial pressure and confining pressure controlled loading. The equipment comprises a loading frame, an axial loading system, a confining pressure loading system and a high-frequency dynamic strain collecting system. The confining pressure loading system is used for loading confining pressure needed by a test on a rock sample placed in a triaxial confining pressure chamber, and dynamically regulating and controlling the confining pressure change caused by lateral deformation of the rock sample in the test process. The axial loading system is used for loading an axial load required by a test and collecting axial displacement and load data; and meanwhile, displacement servo control is completed through axial and lateral strain fed back by the high-speed and high-frequency dynamic strain acquisition system. According to the invention, a high-frequency-response and high-precision servo measurement and control instrument and a servo valve are adopted to carry out real-time control on the axial and lateral pressure of the rock sample, so that a dynamic triaxial test under a medium strain rate loading condition can be carried out on the sample on the premise of eliminating uncontrollable loading of previous test equipment, and more accurate and stable material mechanical properties can be obtained.

The invention belongs to the field of drilling well surrounding rock deformation test, especially relates to a test device and method for deformation of drill holes in a condition with high temperature and high pressure, and solves the technological problem that deformation of wellhole inner walls cannot be test, when the drilling well surrounding rocks are at high temperature of 600 DEG C and under stress of 250 MPa. The device is composed of a servo-controlled rock triaxial heating and loading test system with high temperature and high pressure and a drill hole inner wall displacement optical tracking test system, so that high precision test of drill hole surrounding rock deformation in the condition of high temperature and high pressure is realized. Axial stress, lateral stress, temperature, axial strain, and lateral strain of the drill hole surrounding rocks at different time in the condition which is below the high temperature 600 DEG C and the high stress 250 MPa as well as deformation displacement of the drill hole inner wall are obtained. The test device and method has the advantages of high test precision, reasonable apparatus structure and simple test method.

The invention discloses a hybrid fiber reinforced concrete elastic-plastic constitutive model and a construction method thereof. Based on a uniaxial and true triaxial press test result, the hybrid fiber reinforced concrete three-dimensional space failure criterion, the intensifying / softening criterion and the non-associative plastic flow rule are determined through a corresponding stress-strain (axial strain, lateral strain and volumetric strain) relation curve considering the influences of different fiber types, fiber volume contents and draw ratios, and the incremental type hybrid fiber reinforced concrete elastic-plastic constitutive model reflecting fibration is constructed. The model can accurately describe the mechanical behaviors including multiaxial strength, strain strengthening and softening, constraint sensitivity and plastic flow non-relevancy and has high applicability and extensibility.

A method for achieving uniaxial strain on originally biaxial-strained thin films after uniaxial strain relaxation induced by ion implantation is provided. The biaxial-strained thin film receives ion implantation after being covered by a patterned implant block structure. The strain in the uncovered region is relaxed by ion implantation, which induces the lateral strain relaxation in the covered region. When the implant block structure is narrow (dimension is comparable to the film thickness), the original biaxial strain will relax uniaxially in the lateral direction.

A micromechanical device capable of providing out-of-plane motion and force generation in response to an in-plane strain applied to the device is provided. Embodiments of the present invention comprise one or more islands that are operatively coupled with one or more hinges. The hinges are operative for inducing rotation of the islands when a lateral strain is applied to the structure. In some embodiments, the hinges are also electrically conductive such that they enable electrical communication between the one or more islands and devices external to the structure. Some embodiments of the present invention are particularly well suited for use in biological applications. Some devices in accordance with the present invention are fabricated using conventional planar processes, such as flex-circuit fabrication techniques.

The invention discloses a rockburst tendency grade discrimination method based on an uniaxial compression hysteresis ratio index. The method comprises the following steps: firstly, processing a rock block into a cylindrical test sample, and performing a uniaxial compression test until the rock test sample is destroyed; drawing an axial stress-axial strain curve and an axial stress-lateral strain curve of the rock test sample, and figuring out rock volumetric strain; drawing an axial stress-volumetric strain curve of the rock test sample, determining inflection points of volumetric strain in sequence, using the axial stress corresponding to the inflection points as the damage strength of the rock test sample, using an axial stress-axial strain point corresponding to the damage strength as arock uniaxial compression starting point, setting an interval time between the rock uniaxial compression starting point and a peak strength point of the rock test sample as a hysteresis time T1, setting the interval time between an initial loading point and the peak strength point of the rock test sample as a uniaxial compression time T2, calculating a hysteresis ratio TR according to T1 and T2,and discriminating the rockburst tendency grade to prevent excavation working face damage, equipment damage and casualties caused by rockburst.

A force transducer for measuring compression and / or tension forces includes a rod-shaped deformation body and at least four strain transducers applied on the deformation body and configured for measuring a longitudinal strain and a transverse strain of the deformation body. Front and rear elongate recesses are provided on the front and rear sides of the deformation body at an intersection point between a central longitudinal axis and a central transverse axis of the deformation body. Left and right upper indentations and left and right lower indentations are provided on the deformation body respectively at the four quadrants bounded by the axes. An angle between the central transverse axis and a shortest connecting line between the front elongate recess and the left upper indentation is at least 17° and at most 29°.

The invention discloses an asphalt mixture rut monitoring device and method, and belongs to the field of stress and strain monitoring of pavement structure, which can solve the problems that the existing rutting tests are huge in workload, and the variability of the test results are large. The invention includes: a rutting test piece, a rutting tester, four surface-adhesive FBG sensors, a fiber grating demodulator and a monitoring terminal. The invention uses three FBG strain sensors and one FBG temperature sensor to measure a strain time history curve including creep deformation of the rutting test piece structure surface under the rutting condition by using the characteristic that the FBG sensitively capture structure strain; the ability of the internal particle combination structure ofthe asphalt mixture to diffuse the wheel load at a high temperature is researched, and the development process of the asphalt mixture rutting is revealed from the angle of the lateral strain on both sides of the structure surface rather than the longitudinal depth of the gutters. The mechanical parameters extracted from the strain deformation curve are combined to give evaluation of the anti-rutting performance of the asphalt mixture.

The drive current capability of a pull-down transistor and a pass transistor formed in a common active region may be adjusted on the basis of a strain-inducing mechanism, such as a stressed dielectric material and a stress memorization technique, thereby providing a simplified overall geometric configuration of the active region. Hence, static RAM cells may be formed on the basis of a minimum channel length with a simplified configuration of the active region, thereby avoiding significant yield losses as may be observed in sophisticated devices in which a pronounced variation of the transistor width may be used to adjust the ratio of the drive current capabilities for the pull-down transistor and the pass transistor.