123 results about "Plane stress" patented technology

The invention relates to an online material biaxial static-dynamic performance test platform under service temperature, belonging to the field of precision drive. The large-stroke biaxial synchronous identical-speed or synchronous different-speed displacement output is realized by virtue of four groups of piezoelectric actuators which are orthogonally distributed, and the biaxial static tensile test or dynamic fatigue test for a block-shaped material or a film material with a characteristic size being in a millimeter scale can be carried out under a high / low temperature service condition by combining with an embedded high temperature electrothermal alloy sheet / parr patch. The online material biaxial static-dynamic performance test platform is likely to use in conjunction with a scanning electron microscope with a relatively-large vacuum cavity or other microimaging device with an open-type carrier space, such as an optical microscope, an atomic power microscope and a high speed camera, so that the multimode biaxial static tensile test or the large-frequency-range biaxial dynamic fatigue test can be carried out, and the research for the microstructure evolution behavior and fatigue failure mechanism of various structural materials or functional materials under a complicated service condition such as a high / low temperature condition and a static-dynamic plane stress condition can be facilitated.

The invention discloses a fixed-width press plate blank width control method, and belongs to the technical field of steel rolling automatic control. During the process of laterally rolling the head and the tail of a plate blank by a fixed-width press, the head part and the tail part of the plate blank are in plane stress states; according to the metal flow principle of the head part and the tail part of the plate blank, and tongue and fishtail phenomena can be generated. In order to improve the condition, the widths of the head and the tail of the plate blank are controlled in short stroke by adopting the fixed-width press; under the working condition that stripe steel rolling temperature and rolling cycle are ensured, the severe width failure of the head and the tail of the stripe steel can be improved, and the final rolling target width index is ensured effectively; a pass band guarantees the width index deviation range to be 0-8mm, the yield is improved, and the production cost is saved; and when the plate blank is pressed greatly, similar to the small lateral pressing amount, the outlet width is obtained through pressing one time, the rolling temperature of the stripe steel is ensured, and the rolling cycle is improved.

The invention discloses a crack failure mode determination method and a fatigue life prediction method based on the crack failure mode determination method and is applied to the field of reliability. A crack failure mode of a part is determined based on contribution made by normal strain and shear strain to fatigue damage, energy and critical plane approach are combined, fatigue life prediction models in two modes such as a stretching dominated failure mode and a shearing dominated failure mode are established, and the problem that the prediction error is too large due to the material dispersion property can be effectively solved, so that the prediction life does not far deviate from experiment life; and moreover, a critical plane stress-strain curve relation and a related material constant are introduced into the model establishing process, the influence on mean stress can be reflected, and the model is capable of predicting the fatigue life under proportional and non-proportional symmetrical or asymmetrical loads.

The invention discloses a concrete plane complex stress test device, and relates to a concrete stress test device. The invention aims at solving the problem that when a concrete loading test is carried out by the existing multi-shaft testing loading equipment, the concrete transverse deformation is limited to result in friction, which causes a greater difference between the test result and the practical situation. In the device, a second vertical loader is fixed on the ground at the central position inside a reacting force frame, a first vertical loader is fixed on the underside of the central position of the reacting force frame beam, a first horizontal loader and a second horizontal loader are respectively fixed on the internal sides of a first steel plate and a second steel plate. The device can accomplish the concrete plane complex stress test which is a plane stress test of two-way stressing, two-way pulling, one-way stressing, one-way pulling, shear stressing and shear pulling. A hydraulic servo controls two mutually perpendicular loading directions by a control system and the loading speed and different two-way loading combinations can be adjusted automatically. The device can be used for a load control loading test and also for a deformation control loading test.

An interconnector includes a strip-shaped and electrically conductive member electrically connecting respective electrodes of adjacent solar cells, the conductive member includes a plurality of planar stress relief parts and the stress relief parts are formed at equal pitches. With this structure, a stress due to a difference in thermal expansion coefficient between the interconnector and the solar cell is uniformly alleviated, so that the warp occurring to the solar cell is reduced and the reliability of the connection between the interconnector and the solar cell is improved.

The invention relates to a method of monitoring rusting risk of reinforcement in concrete in situ. The method includes the steps of 1, according to the principle of plane state of stress and stress concentration, applying prestress to rusting monitoring sensing units to enable them to be in a plane state of stress; 2, packaging three sides of each rusting monitoring sensing unit, and reserving one side as a rusting monitoring side; 3, distributing the rusting monitoring sensing units at equal intervals within a rectangular steel frame, before concreting, distributing the rectangular steel frame and the outer surface of concrete at a certain angle in an area to be subjected to reinforcement rusting monitoring, allowing the rusting monitoring sides to face a protective layer, and performing rusting monitoring through continuous strain measurement of different sectional heights of sheets. The method has the advantages that monitoring chloride threshold concentration fronts at different depths is achieved, initial rusting time of the reinforcement is predicted, results are updated according to monitoring data, the rusting monitoring sensing units as deep as the reinforcement allow the final initial rusting time, rusting rate and rusting degree of the reinforcement to be directly monitored.

The invention discloses a method for measuring the residual stress inside the coating, which comprises the following steps: determining the parameters of temperature difference, a coating to be measured and a substrate; calculating the distance delta between a bending moment axial line and the coating, the curvature K of the bending moment axial line and the substrate interface, and the strain component epsilon i of plane direction caused by each layer of the plane stress of the coating; calculating the straining of each layer of the coating according to that epsilon i is equal to epsilon i+K(z+epsilon); and calculating the residual stress sigma i inside each layer of the coating according to that sigma i is equal to Ei'epsilon i. The method not only can accurately measure the residual stress value inside common multilayer coating, but also can accurately measure the residual stress value inside each layer of the functional gradient coating, and provide effective theoretical basis for the optimal design of materials before manufacturing the coating.

Methods of fabricating glass sheets (13) are provided in which the sheets are cut from a glass ribbon (15) composed of a glass having a setting zone temperature range (SZTR). As the glass is drawn, it passes through the SZTR (31) and an across-the- ribbon temperature distribution is produced at at least one longitudinal position along the ribbon to compensate for in-plane stress induced in the sheets (13) when flattened. Through such thermal compensation, glass sheets (13) are produced which exhibit controlled levels of distortion when cut into sub-pieces and thus are suitable for use as substrates in the manufacture of, for example, flat panel displays, e.g., LCD displays.

The invention provides a stress measurement primary stress separation method and device based on an ultrasonic surface wave and belongs to methods and devices of measuring the surface stresses of materials. The separation device comprises an ultrasonic transducer, an ultrasonic pulse transmission receiver, a sampling processing system and an analysis system. The output end of the ultrasonic transducer is connected with the input end of the ultrasonic pulse transmission receiver. The output end of the ultrasonic pulse transmission receiver is connected with the input end of the sampling processing system. The output end of the sampling processing system is connected with the analysis system through a digital oscilloscope. The working stress and the residual stress on the surface of an object are measured through the surface wave. In addition, the principle stress separation method is provided. Replication experiments of two-dimension stress measurement achieve surface wave lossless detection of two-dimension plane stress, a demonstration objet is A3 steel, the engineering application value is high, the experiment precision is high, and the stress measurement principle stress separation method and device are suitable for engineering detection. Through the advantages of ultrasound, lossless detection can be conduced on the single-point multi-dimension stress at any position.

The invention discloses a pressure plate parallelism detection device of a clutch cover assembly, which comprises a hydraulic press, a base, and a bottom plate arranged on the base, wherein a plurality of uprights are arranged on the bottom plate, an upper tray is supported on the uprights, a plurality of dial indicators are arranged on the upper tray, a piston which is controlled to be lifted by the hydraulic press is arranged on the bottom plate, the top end of the piston is provided with a lower tray, a plurality of positioning pins are arranged on the upper end face of the lower tray, a scale block is arranged on the middle of the upper end face of the lower tray, the scale block and the positioning pins jointly support the clutch cover assembly, and the end part of a pole body of the dial indicator penetrates through the upper tray to be in contact with the surface of a pressure plate of the clutch assembly. The invention has the advantages of shortening the time of detecting parallelism so as to improve the production efficiency, being capable of improving the accuracy of detecting the parallelism under the condition that one plane stresses simultaneously, and being capable of lightening labor intensity of an operator due to the simple operation process.

The invention provides a method for monitoring the bending moment of an airplane wing in real time based on an FBG (fiber bragg grating), and the method comprises the following steps: 1, pasting FBG sensors on the airplane wing; 2, converting a central wavelength signal of the FBG sensor into a stress value of a measurement point; 3, carrying out the solving of a stress of the surface of the airplane wing in an axial direction; 4, calibrating the unit flexural rigidity; 5, calculating the bending moment through the stress value of the measurement point. Through the above steps, n groups of FBG sensors are pasted on the airplane wing, and a known concentrated force is applied to the tail end of an airplane wing rigid shaft. Moreover, the relation between the stress and the bending moment is built through the plane stress state of the surface of the airplane wing, thereby achieving an effect of converting the stresses measured by the FBG sensors into bending moments, and solving a problem of the real-time monitoring of the bending moment of the airplane wing.

The invention discloses a stress distribution acquisition method after excavation of a shield tunnel. The method comprises the following steps: S1, establishing a finite element model according to related parameters of the tunnel to be excavated; S2, acquiring stress values and stress distribution condition of position nodes around the tunnel and the tunnel surrounding rock in the finite element model; S3, acquiring stress theoretical values at different position nodes around the tunnel and the tunnel surrounding rock after excavation according to the planar stress of the finite element model; and S4, comparing the stress theoretical values at different position nodes around the tunnel and the tunnel surrounding rock after excavation with the stress values at the corresponding position nodes around the tunnel and the tunnel surrounding rock in the finite element model, and determining the correctness of the stress theoretical values around the tunnel and the tunnel surrounding rock after excavation according to compare result. The method disclosed by the invention verifies and analyzes correctness and feasibility of the stress values acquired by the theoretical method through the comparative result so as to obtain the stress distribution condition of the shield tunnel after excavation.

The invention relates to a burst speed simulative analysis method for a bolt-free structure turbine disk baffle. The method comprises the following steps: establishing a two-dimensional section model capable of accurately reflecting a blisk structure form; arranging an elastic material model; according to model features, creating an axial symmetric unit and a plane stress unit; setting a boundary condition and a load; calculating solving parameters; judging whether a solving process is converged or not; if the solving process is converged, performing post-processing to output a stress calculation result; and according to a burst criterion, calculating a baffle burst speed. According to the method, the burst speed simulative analysis is carried out for the bolt-free structure baffle, so that the baffle is ensured to work safely and reliably within a design speed range, the hidden troubles of faults in aero-engine design are reduced, and decision bases and technical support are provided for analyzing occurred engine shroud faults.

The invention discloses a method for carrying out non-contact measurement on plane transformation by using a low-dimensional nano material. The method specifically comprises the following steps: preparing materials; preparing systems; calibrating parameters; carrying out Raman measurement; and processing data. When the low-dimensional nano material serves as a sensing medium, stress sensing key parameters of the materials are obtained based on calibration and each stress component of a micrometer scale measuring point or full-field distribution of each plane stress component in a micro-region is directly measured by a polarization microscopic Raman instrument. Compared with a current relative technology, the method has the advantages that a Raman polarization sensitivity function of the specific low-dimensional nano material is not introduced, a common relation formula is given from a generalized angle, and a pure sensitive coefficient detected by calibration is used for representing a polarization selection characteristic of the nano material so that the dependency on the purity of a sensing medium material is completely eliminated and the method has a broad spectrum property and usability. The method can be used for relative application occasions of a plurality of fields including an experiment research of micro-scale mechanical behaviors, testing of mechanical properties of MEMS (Micro Electro Mechanical Systems) micro devices and the like.

The invention discloses a method for determining residual butt welding stress of aluminum alloy sheets. On a condition of a plane stress field formed at butt welding joints of sheets, the sheets are slitted by a linear cutting method along weld seams longitudinally or transversely, so that welding stress can be released. Precise marked lines are engraved on a measuring surface of a weld part before welding, distances of the marked lines are measured by a microscope before welding, after welding and after slitting respectively, a corresponding strain increment can be solved according to increment of the distances of the marked lines, and finally residual stress is solved according to the strain increment. The method is visual, simple and convenient and applicable to determining residual butt welding stress of aluminum alloy sheets on testing conditions; and measured results are good in repeatability, reproducibility and comparability.

The invention discloses a method for measuring the residual stress of a substrate, which comprises the following steps: determining the parameters of temperature difference, a coating to be measured and the substrate; calculating the distance delta between a bending moment axial line and the coating, the curvature K of the bending moment axial line and the substrate interface, and the strain component epsilon s of planar direction caused by the plane stress of the substrate; calculating the straining of the substrate according to the formula that epsilon s is equal to epsilon s+K(z+epsilon); and calculating the residual stress sigma s inside the substrate according to the formula that sigma s is equal to Es'epsilon s. The method not only can accurately measure the residual stress value inside the substrate of common multilayer coating, but also can accurately measure the residual stress value inside the substrate of the functional gradient coating according to the elastic mechanic principle, and provide effective theoretical basis for the optimal design before preparing the coating.

The invention discloses a novel acoustic-emission ground-stress-field measuring technology based on a plane stress condition, which comprises the following concrete steps of: supposing that the vertical direction is a known principal stress direction sigmaZ, and obtaining the magnitude of a principal stress according to a formula sigmaZ=gammad; in the horizontal direction, sampling a rock sample in the two mutually vertical directions and the directions with included angle of 45 degrees with the two directions; and loading and recording data, analyzing to obtain a Kaiser point, computing the magnitudes and the directions of the two principal stresses in the horizontal direction according to a theoretical computing formula, and adding the supposed sigmaZ to realize the three-dimensional stress measurement of a ground stress. The novel acoustic-emission ground-stress-field measuring technology based on the plane stress condition is a novel ground-stress-field testing technology, can make up for the deficiency of a traditional testing method, simultaneously can greatly save the measuring consumption, has the advantages of strong operability, accurate measurement and the like, is combined with means, such as rock mass mechanical testing, numerical simulation analysis and the like, can supply a powerful scientific basis for geotechnical engineering design and is a brand-new and internationally-advanced ground-stress-field testing technology.

The invention relates to a material plane stress detection device, in particular, an apparatus for measuring the plane stress of an anisotropic material. The objective of the invention is to solve the problem of low measurement accuracy of an existing stress detection method. The device includes an ultrasonic transducer group, an ultrasonic oblique incidence wedge, a signal generator, a digital oscilloscope and analysis processing software; a first ultrasonic longitudinal wave excitation probe, a second ultrasonic longitudinal wave excitation probe and a third ultrasonic longitudinal wave excitation probe are all connected with the signal generator; a first ultrasonic longitudinal wave receiving probe, a second ultrasonic longitudinal wave receiving probe and a third ultrasonic longitudinal wave receiving probe are all connected with the digital oscilloscope; the signal generator is connected with the digital oscilloscope; and the analysis processing software is connected with the digital oscilloscope. According to the device, critical refraction longitudinal waves are adopted as a detection wave source based on an anisotropic three-way method. The device has the advantages of high measurement efficiency and simple operation. The device can be widely applied to the detection and analysis of plane stress in anisotropic materials in aerospace, weapon manufacturing and vehicle fields and so on.

The present invention discloses a synchronous test method for asphalt mixture dynamic stretching, compression modulus and Poisson's ratio. The method places the asphalt mixture split test piece in a split metal fixture of a loading test system, installs a horizontal radial displacement sensor and a vertical radial displacement sensor on end surface of the test piece, and applies a vertical dynamiccompression load to the test piece at a prescribed temperature and frequency. According to Hooke's law under a two-dimensional plane stress state of the split test, the present method deduces an analytical expression of the dynamic compression modulus and dynamic stretching modulus of the asphalt mixture, according to a relationship model between the dynamic compression modulus and the Poisson'sratio, through the method of simultaneously determination of the dynamic compression modulus, the dynamic stretching modulus and Poisson's ratio of the asphalt mixture, the method greatly improves test efficiency and accuracy, and is beneficial to further scientifically and reliably evaluate dynamic response characteristics of the asphalt mixture under the two-dimensional stress conditions, and has good application and promotion value.

The invention relates to a corrosion test accelerating device which is characterized by comprising a gradation loading system and a lever loading system, wherein a poise is hung at one end of a lever of the lever loading system; the other end of the lever is connected with the gradation loading system; a supporting point is fixed on a bearing plane through an upright post and can move along the lever; each stage of the gradation loading system consists of a narrow plate and a sling; a sling in the middle of any middle stage narrow plate is connected with one end of a last stage narrow plate; slings at two ends of each narrow plate are connected with the middles of two next stage narrow plates; slings at two ends of a lowest stage narrow plate of the loading system are fixed on the bearing plane through bolts; a sling in the middle of each narrow plate is connected with a thin-plate sample; the other end of the sample is drawn by the sling, and is then fixed on the bearing plane; and a corrosion environment test box is clamped on the middle part of the thin-plate sample. In the invention, the load on the sample can be adjusted by changing the position of the supporting point, multiple groups of accelerated test can be performed simultaneously, loads applied to all samples are same, the thickness of the sample is relatively small, and a plane stress state is approximately met.

A method of measuring plane stress of an anisotropic material relates to a measuring method of plane stress of a material and is aimed at solving the problem that a conventional stress detection method is not high in measuring precision. The method includes the following steps: firstly, preparing a material to be measured; secondly, designing four unidirectional stretching calibration experiments, and obtaining four sound time difference-stress curves; thirdly, conducting linear fitting on the four sound time difference-stress curves, and obtaining four sound stress coefficient combination expressions and values; fourthly, conducting simultaneous equations on the four expressions, that is to say, obtaining a relation between sound time difference signals and plane main stress; and fifthly, utilizing a measuring device to measure the material to be measured in a plane stress state, detecting sound time difference values in three different directions respectively, conducting substitute-type simultaneous equations, and thus obtaining the magnitude [sigma]1 and [sigma]2 and the direction [theta] of plane main stress. The method, based on the critical refraction longitudinal wave principle, is easy to operate, is high in efficiency, is suitable for all anisotropic materials, and can be widely applied to detection and analysis of plane stress of composite material laminated boards in the field of aerospace, weapon manufacture, vehicles, etc.

A method for determining plane stresses on an in-service steel structure member based on phase spectrum of ultrasonic transverse wave, including: calibrating stress-spectrum parameters k and c of a replica of the in-service steel structure member; determining a first response frequency of a phase difference and a maximum value of a derivative function of the phase difference of an ultrasonic transverse wave echo of the in-service steel structure member, and obtaining a polarization angle of ultrasonic transverse wave components generated by a birefringence effect; solving a plane normal stress difference and a plane shear stress inside the in-service steel structure member; and separating normal stresses by a shear difference method to obtain three independent plane stress components.

The invention provides a plane stress determination method and device based on magnetic Barkhausen noise. The plane stress determination method based on the magnetic Barkhausen noise comprises the steps that circumferential magnetic Barkhausen noise of a measurement point is measured; and a plane stress state and a stress tensor of the measurement point are determined according to the circumferential magnetic Barkhausen noise and a pre-generated relation model of a magnetic Barkhausen noise characteristic value and plane stress. The principal stress and the principal direction of the measurement point can be accurately calculated by using the circumferential magnetic Barkhausen noise, and the positive stress of the measurement point in each direction can also be obtained.

The invention belongs to the technical field of radar antennas, and particularly discloses a method for an electrode of a satellite-borne electrostatic forming membrane reflector unfolding antenna. According to the method, the characteristics of systematic manufacturing and installing of the electrode are sufficiently considered, and clipping and lofting are carried out on a flexible cable and the membrane electrode in a separated mode. Due to the fact that tension of the flexible cable is easily measured, it is emphasized that flexible cable clipping is carried out in the tensioning state, and the flexible cable clipping accuracy is controlled. The hook face unfolding and stress releasing principle can not be easily used when tension of a membrane is measured, the membrane is clipped in the plane stress-free state, and the manufacturing clipping accuracy of the membrane can be effectively controlled. Then the flexible cable is connected with the membrane electrode through a positioning template in the tensioning state, and the installation accuracy of the electrode can be effectively controlled. The method is reliable in principle and easy and convenient to operate, and the method for effectively controlling manufacturing and installing of the high-voltage electrode of the electrostatic forming membrane reflector unfolding antenna is provided.

A microelectromechanical force / pressure sensor has: a sensor die, of semiconductor material, having a front surface and a bottom surface, extending in a horizontal plane, and made of a compact bulk region having a thickness along a vertical direction, transverse to the horizontal plane; piezoresistive elements, integrated in the bulk region of the sensor die, at the front surface thereof; and a cap die, coupled above the sensor die, covering the piezoresistive elements, having a respective front surface and bottom surface, opposite to each other along the vertical direction, the bottom surface facing the front surface of the sensor die. A conversion layer is arranged between the front surface of the sensor die and the bottom surface of the cap die, patterned to define a groove traversing its entire thickness along the vertical direction; the piezoresistive elements are arranged vertically in correspondence to the groove and the conversion layer is designed to convert a load applied to the front surface of the cap die and / or bottom surface of the sensor die along the vertical direction into a planar stress distribution at the groove, acting in the horizontal plane.

The invention discloses a bridge cable corrosion monitoring method based on stress concentration in a plane stress state. The method comprises the following steps: with a high-strength steel wire sheet with the same mark as an inner steel wire of a cable as a sensitive element, reserving one side face of the section of the steel wire sheet as a corrosion monitoring surface; setting continuous strain measuring points at different heights on the section of the steel wire sheet; applying pre-tensioning stress same as dead load cable force on the cable to the steel wire sheet, and anchoring the steel wire sheet in an auxiliary frame, wherein the steel wire sheet is in a plane stress state; arranging a corrosion monitoring device in a high-density polyethylene jacket or an anchor head protective cover of the cable; and judging initial time of corrosion or stress corrosion and calculating the corrosion degree, the corrosion rate and stress corrosion crack depth according to monitoring data when sudden change of local strain of the corrosion monitoring surface is caused. The method has the advantages of high sensitivity, stability and reliability, and the corrosion and stress corrosion states of the inner steel wire in the cable are quantitatively monitored for a long time under the condition that a local micro-environment on the surface of the steel wire is not damaged.

The invention relates to a reservoir-induced earthquake probability calculation method and belongs to the field of analysis of reservoir-induced earthquakes. The reservoir-induced earthquake probability calculation method comprises the following steps: based on coulomb stress of a fault plane, establishing a functional function of fault earthquakes; taking a fault plane cohesive force, a fault plane friction coefficient, an actual water head of earthquake part pore water, coordinate plane stress, coordinate plane positive stress and a direction cosine of the fault plane in the functional function as random variables; calculating the probability of reservoir-induced earthquakes by applying a reliability theory. According to the reservoir-induced earthquake probability calculation method, factors, which influence the reservoir-induced earthquakes, are considered as the random variables and distribution types of the random variables are analyzed; the change of the stress of the fault plane is analyzed by adopting a coulomb stress theory which is widely adopted; based on the reliability theory, the probability of the reservoir-induced earthquakes is calculated and a novel concept is provided for analyzing the reservoir-induced earthquakes.

The invention relates to a steel member plane stress detection method based on ultrasonic transverse and longitudinal wave combination. The method comprises the following steps of: acquiring a to-be-detected in-service steel structure member copy test piece; performing a calibration experiment on the copy test piece, calibrating all stress-acoustic elasticity parameters of the copy test piece, and obtaining a plane stress information detection formula by taking the transverse wave acoustic time difference and the reciprocal of the square of longitudinal wave acoustic time under the center frequency of a probe as an independent variable and taking each stress component of plane stress as a dependent variable; determining a detection point, carrying out an ultrasonic experiment on the in-service steel member, and obtaining transverse wave and longitudinal wave echo time domain signals at the detection point; and performing spectrum analysis processing on the captured time domain signals to obtain the transverse wave acoustic time difference and the longitudinal wave acoustic time under the center frequency of the probe, and substituting the transverse wave acoustic time difference and the longitudinal wave acoustic time into a plane stress detection formula of the copy test piece to obtain plane stress information of the steel member. According to the method, the plane stress information of in-service steel plate components made of different materials and with different thicknesses can be directly detected, and a testing instrument is convenient to install, low in cost and easy to implement.