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988 results about "Fatigue testing" patented technology

HIGH CYCLE FATIGUE. Historically, high cycle fatigue (LCF) refers to situations that require more than 10 4 cycles to failure where stress is low and deformation is primarily elastic. In high-cycle fatigue situations, materials performance is commonly characterized by an S-N curve, also known as a Wöhler curve .

Material mechanical property in-situ testing system and method in dynamic and static load spectrum

The invention relates to a material mechanical property in-situ testing system and method in a dynamic and static load spectrum, and belongs to the field of mechanical tests. The system integrates the following functions: a static testing function of biaxial drawing and shearing in an orthogonal plane, a shearing static testing function, a double shaft pull-pull mode fatigue testing function, and a static/dynamic press testing function. A complicated static/dynamic load spectrum can be established. Multi-mode composite load mechanical property evaluation can be performed on a film material or a block material, for example: high-cycle fatigue tests based on double-shaft pre-stretching load and impact press tests based on double-shaft stretching-shearing pre-load. At the same time, special defects are pre-fabricated on the central area and cross shaped arm area of a test piece; the analysis functions of a variable-zoom optical imaging system or a digital speckle strain analysis system can be utilized; the provided system and method can also be used to research the deformation behavior and cracking expansion rules of micro defects in a component under a multi-dimensional stress, and an evaluation tool is provided for performance degradation rules of products and optimized preparation method of materials.
Owner:JILIN UNIV

Steel wire fretting fatigue testing machine and method

The invention relates to a steel wire fretting fatigue testing machine and a method. The testing machine mainly comprises a horizontal loading device, an axial clamping device and an axial tensile compression device, wherein the horizontal loading device consists of a concave horizontal support saddle, a guiding support saddle, a wedged slide block, a loading steel wire, a pressure sensor, a loading rod and a locking nut; the axial clamping device consists of a spoke-type tensile compression sensor, a threaded rod connected with the spoke-type tensile compression sensor and an upper holding block fixed on the threaded rod; and the axial tensile compression device consists of an oil cylinder, a threaded rod connected with the piston of the oil cylinder and a lower holding block fixed on the threaded rod. The steel wire fretting fatigue testing machine has the advantages that by exerting horizontal set load on an axial steel wire through the horizontal loading device and by acting axial fatigue stress on a steel wire sample through the axial clamping device and the axial tensile compression device, the testing machine realizes fretting fatigue test of the coaction of fretting wear and axial fatigue stress of the steel wire sample; dynamic adjustment of the concave horizontal support saddle ensures that an axial fatigue steel wire does not generate bending stress; moreover, fluctuation ranges of both amplitude and frequency are wide and easy to control and measure by utilizing computer program.
Owner:CHINA UNIV OF MINING & TECH

Gas circulation charging/discharging fatigue test system for full-automatic high pressure vessel

The invention discloses a full-automatic high-pressure container gas circular charging and discharging fatigue test system which not only can realize the full-automatic control of the high-pressure gas circular charging and discharging fatigue test but also can carry out the on-line automatic detection to the fatigue condition of the high-pressure container. The automatic control of the circular charging and discharging is realized through the dynamic response signals of a temperature sensor arranged inside the tested container, the dynamic response signals of each pressure sensor on the high-pressure pipelines and switching of solenoid valves controlled by the control strategy. The gas medium in the circular charging and discharging process can be recycled after the pressurizing by a pressure-releasing receiving tank and a gas compressor so as to avoid the gas waste and environment contamination. The dynamic fatigue states of the high-pressure container in the circular charging and discharging process are acquired through the changing of response signals of a hydrogen sensor arranged in a sealed bin of the tested container and the response signals of a strain sensor stuck to the surface of the tested container; and when the released hydrogen concentration reaches the set value or the strain of the container material exceeds the set value in the charging and discharging process, the fatigue test system is closed automatically.
Owner:TONGJI UNIV

Online material biaxial static-dynamic performance test platform under service temperature

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.
Owner:JILIN UNIV

Device for testing composite asphalt pavement interlayer shear fatigue, and method thereof

The invention discloses a device for testing composite asphalt pavement interlayer shear fatigue, and a method thereof. According to the present invention, a skew shearing experiment is adopted to determine the composite asphalt pavement interlayer shear fatigue lives under different temperature conditions. The device comprises a loading bar, a load testing system, a pressing block, a supporting block and a support platform, wherein the pressing block and the supporting block are provided with a concave part, when the loading rod loads, a specimen requiring test is positioned in a space formed by docking of the two concave parts. The testing method is: placing the specimen in the supporting block and the pressing block, loading on the specimen through a testing machine to generate the skew shearing failure to obtain the maximum failure load, and carrying out the shear fatigue experiment under the repeated load effect according to 0.2-0.8 times the maximum failure load. The device and the method are simple and easy to operate, the actual stress state of the composite asphalt pavement can be accurately simulated, and the important significances are provided for the designs and the evaluations of the composite asphalt pavement interlayer shear property and the interlayer structure and material, and the design of the asphalt layer thickness.
Owner:CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY

Fatigue test device for vehicle body thin plate, and test method thereof

The present invention discloses a fatigue test device for a vehicle body thin plate, and a test method thereof, and belongs to the field of material fatigue test. The test device comprises: a centering apparatus and an anti-bending constraining apparatus. The centering apparatus comprises a vertical column and two centering clamping blocks, wherein the vertical column is provided with a reference plane correspondingly attaching to holding fixtures so as to make a center line of a fatigue specimen parallel to the reference plane, and the two centering clamping blocks are intervally and vertically arranged on the reference plane of the vertical column, such that the fatigue specimen is centered to a center line of test fixtures. The test method comprises: selecting a thin plate fatigue specimen and measuring a static tension curve; carrying out calibration on test force, selecting the initial test force, and setting a condition fatigue limit of the material; adopting the fatigue test device to carry out centering and anti-bending constraining on the fatigue specimen, and adopting a testing machine to carry out a fatigue test on the fatigue specimen. According to the present invention, uniformity of the test process is ensured and influence on the tested result due to additional factors is reduced by the centering apparatus and the anti-bending constraining apparatus, the test efficiency is improved, and the test cost is saved.
Owner:CHERY AUTOMOBILE CO LTD

Fatigue-tesing machine for ball socket bearing of helicopter main rotor

The invention discloses a fatigue testing machine of a ball socket bearing of a main rotor of a helicopter. The fatigue testing machine is characterized in that a first rolling guide (26) and a second rolling guide (29) are fixedly connected to a central upright post (16); a first supporting sleeve(25) is fixedly connected on the first rolling guide (26); a second supporting sleeve (30) is fixedly connected to the second rolling guide (29); both the first supporting sleeve (25) and the second supporting sleeve (30) support a main shaft of a rotor wing (3); an inner hole of an inner ring (24) of the ball socket bearing of an auto bank unit of a main rotor is matched with an outer cylindrical surface of the main shaft of the rotor wing(3); the inner ring (24) of the ball socket bearing of the auto bank unit of the main rotor is sheathed with an outer ring thereof to form a spherical pair. The invention can accurately simulate the real working conditions of the ball socket bearing of the auto bank unit of the main rotor, such as the temperature, the load, and the like, and accurately simulate the real movements of the ball socket bearing of the auto bank unit of the main rotor, such as the speed, the acceleration and the like. The invention has the advantages of compact structure, beautiful appearance and convenient operation and maintenance.
Owner:YANSHAN UNIV

Rubber diaphragm antifatigue test device

The invention relates to a fatigue resistance testing device for a rubber membrane. A reciprocating transmission mechanism adopts a double-eccenter connecting rod type structure and is positioned on the top of the device; the top end of a reciprocating rod is connected with a counter; the reciprocating transmission mechanism is in driving communication with a motor arranged on the right top of the device; the bottom end of the reciprocating rod is in mechanical connection with a membrane clamping mechanism; the bottom of the center of the clamping mechanism is provided with a balancing spring; the right end of the membrane clamping mechanism is communicated with an air pressure pump through a valve; the middle part of an air inlet pipe is connected in series with an air pressure sensor and an air pressure meter; the middle part of the reciprocating rod is provided with a fixing piece; the upper part and the lower part of the reciprocating rod are provided with a sliding sleeve respectively; and the sliding sleeve restricts the moving direction of the reciprocating rod. The fatigue resistance testing device has the advantages of simple structural principle, large testing range, high efficiency, convenient operation and use, safe and reliable operation and good automation degree.
Owner:QINGDAO UNIV

Flexural fatigue mode adjustable tester for testing mechanical properties of materials, and testing method thereof

The invention relates to a flexural fatigue mode adjustable tester for testing mechanical properties of materials, and a testing method thereof, belonging to the field of precision instruments. The tester comprises a flexural fatigue loading unit, a test piece clamping unit, an associated movement unit and a precise detection unit, wherein the flexural fatigue loading unit is powered by a direct current servo motor, a crank and rocker mechanism is driven to realize reciprocating swinging of a rocker by primary worm gear reduction, the rocker drives the clamping unit to realize reciprocating rotation, a bended test sample is repeatedly bent along with the reciprocating rotation of the clamping unit, and the associated movement unit does associated rotation and translation under the driving of the bended test sample. The tester has the advantages that the error of converting bending moment in three-point bending loading is avoided, the influence of the friction force of a support roller on the testing result is avoided, the bending moment and the bending angle can be accurately measured, different fatigue modes can be realized, and fatigue testing with different stress amplitudes and different average stresses can be realized.
Owner:JILIN UNIV

High-frequency fatigue testing machine dynamic load error compensation method

A high-frequency fatigue testing machine dynamic load error compensation method includes the following steps: 1) establishing a three-freedom-degree vibration mechanical model having the system with damping, and analyzing relevant factors affecting a dynamic load error; 2) determining a key factor affecting the dynamic load error; 3) making a pasted strain piece of a middle section of a calibration rod into a calibration sensor, and calculating the stiffness by using a finite element method; 4) taking a calibration sensor with known stiffness, fixing the upper end to a testing machine, allowing the lower end to press a standard force sensor, applying a static load, and calibrating by the standard force sensor; 5) calculating the difference between the amplitude of the calibration sensor and the amplitude of the force measuring sensor, and recording the corresponding calibration sensor stiffness; 6) changing the calibration sensors with different stiffness, repeating the step 4) and the step 5), and thus obtaining a relation curve of the error and the sensor stiffness; and 7) carrying out error compensation on a corresponding dynamic load measurement value by the calculated error value. The measuring accuracy of the fatigue testing machine dynamic load is effectively improved.
Owner:ZHEJIANG UNIV OF TECH

High-pressure fatigue testing device and method

ActiveCN103808569AValid inspectionMeet the needs of hydraulic fatigue testingMaterial strength using tensile/compressive forcesLower limitPressure cycling
The invention relates to the technical field of a high-pressure fatigue test, and particularly relates to a complete high-pressure fatigue testing device and method in which the highest testing pressure is 70MPa. According to the high-pressure fatigue testing complete device and method provided by the invention, a large-flow high-pressure piston pump is used for directly pressurizing a test piece; after the value of a pressure reaches a set test pressure value, the pressure is kept for a certain period; a double-position three-way electromagnetic valve is switched to control an air cylinder to reset; an unloading valve is automatically reset to be switched on for unloading; when the value of the pressure reaches a lower limit pressure value, the pressure is kept for the certain period, and the pressure is increased again. With the adoption of the high-pressure fatigue test device and method provided by the invention, a pressure cycling processing of pressure increasing, pressure maintaining, pressure decreasing and pressure keeping can be completed, so that the cycle of stress when a high-pressure container or pipe piece is forced in work can be simulated; the one-time cycle is performed, and the test time is added by one until a set cycle time is reached or a test container is cracked, so as to effectively test whether the fatigue service life and the limit of the test piece can meet using requirements or not. The device has the advantages of being simple in system, high in reliability, good in simulation effect and the like.
Owner:HEFEI GENERAL MACHINERY RES INST +1

Driver fatigue driving detection system based on machine vision and detection method

The invention provides a driver fatigue driving detection system based on machine vision and a detection method, and belongs to the technical field of machine vision and machine learning. The system belongs to a non-intrusive type detection system. When detection is performed, needed information is acquired through a camera, normal driving of a driver is not influenced, and equipment is low in price and small in size; and a Bluetooth camera only needs to be installed in a vehicle, and app software is installed in a mobile phone, and then fatigue detection for the drive can be achieved. Information acquisition of the system is convenient and easy; when the system is used, only the camera is externally added, and then the system can adapt to any-type vehicle and any road condition; and the system has a consistent fatigue judgment criteria and the high fatigue judgment accuracy rate. The system integrates fatigue characteristics of eyes, a mouth and a face, the accuracy rate of fatigue judgments in complex driving environment is improved, and system parameters are rapidly updated through combination with the machine learning according to feedback of the driver so that the system adapts to different characteristics of different drivers. The system has the advantages of short training time, the rapid computing speed and high real-time performance.
Owner:NORTHEASTERN UNIV

Testing device and testing method for fretting fatigue of end-tooth structure

The invention discloses a testing device and a testing method for the fretting fatigue of an end-tooth structure. The testing device comprises a concave tooth fixing assembly, a convex tooth clamping assembly and a normal force loading assembly, wherein the concave tooth fixing assembly is used for realizing the fixation of a concave tooth test piece; the convex tooth clamping assembly is used for realizing the loading of a convex tooth test piece; the normal force loading assembly is used for realizing the application of a load in a horizontal direction; a fretting fatigue testing level loading device adopts a symmetrical structure layout and the load is realized by a hydraulic loading system; the hydraulic loading system adopts a closed force system framework structure and has no output of external force, and the load of a fatigue tester in the vertical direction is not influenced; and a concave tooth test piece bears a pre-tightening force load in the horizontal direction and is tightly pressed by a concave tooth pressing plate in the vertical direction, so that the loading direction in the horizontal direction of a loading process keeps unchanged. According to the testing device, a common single-shaft fatigue tester is matched by similarly simulating the stress condition of end teeth under an actual working environment, so that a fretting fatigue test of an end-tooth structure simulating piece can be carried out and the experiment cost is reduced.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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