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150 results about "Cyclic loading" patented technology

Cyclic Loading. Definition - What does Cyclic Loading mean? Cyclic loading is defined as the continuous and repeated application of a load (fluctuating stresses, strains, forces, tensions, etc.) on a material or on a structural component that causes degradation of the material and ultimately leads to fatigue.

High-rise pile cap equipment under horizontal load and centrifuge test method for foundation bearing characteristics thereof

Disclosed in the present invention are high-rise pile cap equipment under a horizontal load and a centrifuge test method for foundation bearing characteristics thereof. The equipment comprises a model box, a sand layer, a model pile cap, at least eight model piles, a horizontal loading device, at least two laser displacement sensors, an axial force sensor, and a plurality of strain gauges. The method comprises: S1, performing one-way horizontal loading on high-rise pile cap equipment under a horizontal load to obtain an ultimate foundation bearing capacity situation, a model pile body axial force distribution situation, a pile foundation axial force comparison situation, a model pile body bending moment distribution situation, and a model pile body bending moment comparison situation of the equipment; and S2, performing one-way variable amplitude cyclic loading on the high-rise pile cap equipment under the horizontal load to obtain a foundation displacement situation, an effect of the number of cycles on foundation stiffness, an effect of a cyclic load amplitude on the foundation stiffness, and a foundation inclination situation. In this way, the foundation design of the high-rise pile cap can be optimized, and a basis and a reference for evaluating safety of foundation long-term service are provided.
Owner:TIANJIN RES INST FOR WATER TRANSPORT ENG M O T

Slope stability evolution prediction method for cumulative damage mechanism of main shock sequence and aftershock sequence

The invention relates to the technical field of slope stability prediction, in particular to a slope stability evolution prediction method of a main shock and aftershock sequence cumulative damage mechanism. The method comprises the following steps: determining an initial strength parameter of a slope sliding surface rock-soil body and a dynamic strength attenuation parameter under the action of a main shock and aftershock sequence through an indoor cyclic load test, and establishing a cumulative damage model; three-dimensional side slope geometric features are obtained, and the spatial orientation and the stress direction of a potential sliding surface are determined; calculating a dynamic sliding force in combination with seismic oscillation parameters, and updating an effective strength parameter and a dynamic anti-sliding force of the sliding surface in real time; and carrying out staged calculation and dynamic evolution analysis by adopting a limit equilibrium method or a strength reduction method. According to the method, by introducing a rock-soil body strength accumulated damage and progressive attenuation mechanism under the cyclic action of the main and aftershock sequences, the damage accumulation process and the stability evolution law of the slope stability along with the development of the main and aftershock sequences are described, so that the progressive instability process and the accumulated instability risk driven by the aftershock after the main shock is triggered can be identified.
Owner:ANHUI UNIV OF SCI & TECH

Anti-buckling tool for low-cycle fatigue test sheet metal structure

The utility model relates to the technical field of low-cycle fatigue tests, and discloses an anti-buckling tool for a low-cycle fatigue test sheet metal structure, which comprises a fixing assembly and a guide assembly, the fixing assembly comprises an upper fixing piece I, an upper fixing piece II, a lower fixing piece I and a lower fixing piece II, two screws are connected between the first upper fixing piece and the second upper fixing piece, two screws are connected between the first lower fixing piece and the second lower fixing piece, and cushion blocks are arranged on the inner side faces of the first upper fixing piece, the second upper fixing piece, the first lower fixing piece and the second lower fixing piece. Through the fixing assembly, the sample can be conveniently and quickly assembled, the low-cycle fatigue test requirement of the sheet metal structure can be met, and the lateral buckling instability phenomenon between a clamping part of equipment and the buckling-restrained tool can be reduced; through the guide assembly, when the sample bears a tension and compression cyclic load, the lateral buckling instability phenomenon in the thickness direction is prevented, and the stability of the sample is further enhanced.
Owner:GUOHE GENERAL (QINGDAO) TEST & EVALUATION CO LTD

Large-scale visualized direct shear test device and test method for geosynthetics

The invention discloses a large-scale visualized direct shear test device and method for geosynthetics. The device comprises a main frame, an upper shear box, a lower shear box, a normal cyclic loading system, a horizontal cyclic shear loading system, a data acquisition system and a visualized monitoring system. The direct shear test device is characterized in that the direct shear test device can perform normal and horizontal cyclic loading at the same time, and normal stress with different frequencies and amplitudes can be applied according to needs to simulate a test of the characteristics of the reinforcement-soil interface under the cyclic loading effect; one side wall of the upper shear box and one side wall of the lower shear box are transparent observation windows, and a high-speed camera and a digital image analysis method are combined, so that the shear band evolution process can be visually observed and quantitatively analyzed; the shear box is large in size, and the size effect is effectively overcome. According to the invention, the interface characteristics under the cyclic load effect in the road engineering can be reflected more truly and comprehensively, the size and the function of the shear box are comprehensive, and the interface mechanical characteristics and the interaction mechanism under various working conditions can be simulated.
Owner:HUBEI UNIV OF EDUCATION

Impact fatigue test system for simulating gun firing pin working condition environment

The invention belongs to the technical field of impact fatigue tests of metal materials, and relates to an impact fatigue test system for simulating a working condition environment of a gun firing pin, which can perform high-frequency cyclic loading of 200MPa-500MPa, microsecond (mu s) level impact pulse and more than kilohertz (kHz), and synchronously simulate the working condition environment. High-energy, high-frequency and short-pulse impact loading under the gun and gun firing pin working condition is carried out through the high-frequency impact generation subsystem, and the dynamic mechanical environment in actual service is effectively simulated; the environment simulation subsystem is used for accurately controlling the temperature, the concentration and the pH value of media such as salt mist and seawater, and is synchronously coupled with mechanical shock, so that mechanical-electrochemical synergistic damage conditions are truly represented; dynamic stress, strain, electrochemical parameters and surface topography in the impact process are synchronously monitored through a multi-parameter synchronous acquisition subsystem, and complete data support is provided for researching the damage evolution law of a material under a complex load; the repeatability and the safety of the test are ensured through the modularized sample clamp subsystem and the dynamic sealing design.
Owner:CHINA SHIPBUILDING INDUSTRY CORPORATION NO725 RESEARCH INSTITUTE

Method for testing degradation characteristic of bearing performance of recoverable anchor rod under cyclic load

The invention relates to the technical field of geotechnical engineering anchoring, in particular to a method for testing the degradation characteristic of the bearing performance of a recyclable anchor rod under cyclic loading. The method comprises the following steps: preparing a unit body sample anchor-rock interface unit body sample, simulating weathered soft rock according to a specific ratio, pouring a self-compacting concrete anchoring body, and curing and forming; setting a combined parameter of a reference load ratio and a load cycle index, applying a triangular wave cyclic load to simulate a traffic condition, and executing a pull-out test to collect load-displacement data; constructing a two-parameter coupled shear strength degradation model based on test data, and proposing a shear stress-displacement curve model; an anchor rod load transfer control equation is established in combination with the Poisson effect, and shear stress distribution of the anchoring section is iteratively solved by adopting a discrete recursion method; the model is verified through a foundation pit engineering case, the ultimate bearing capacity degradation law of the anchor rod under long-term cyclic loading is predicted, and it is proved that the model can guide engineering safety design. According to the method, the coupling characterization of the cyclic load parameter and the interface degradation mechanism is realized.
Owner:HUNAN UNIV

Water conservancy project risk assessment method based on big data

The invention relates to the technical field of risk analysis, in particular to a water conservancy project risk assessment method based on big data, which comprises the following steps: acquiring deformation and water level signals and converting the signals into a sequence, generating an original monitoring sequence based on a timestamp, identifying a whole process span and intercepting and generating a periodic data set, generating a complete monitoring sequence by using interpolation filling, constructing a water level displacement closed curve, calculating a vector product difference value to obtain a geometric area, calculating an arithmetic mean value to generate a centroid coordinate, obtaining a dissipated energy increase coefficient and a structure permanent deformation cumulant, and generating an evaluation result based on threshold comparison. According to the method, the two-dimensional phase space model is established, the structure response is converted into the closed trajectory curve, the hysteresis loop area and centroid offset are calculated, energy dissipation and deformation accumulation of the structure under cyclic loading are quantitatively represented, abnormal plastic damage is effectively stripped, and early recognition of the potential irreversible damage risk of the structure is achieved.
Owner:HUNAN HONGXINLI ENG TECH CO LTD

A method and apparatus for fabricating complex hollow structures using pulsed DC and induced eddy current cyclic loading assisted diffusion bonding.

This invention discloses a method and apparatus for fabricating complex hollow structures using pulsed DC and induction eddy current cyclic loading assisted diffusion bonding, relating to a method for assisted heating diffusion bonding. It achieves efficient and uniform heating of metallic materials. Step 1: Prepare a predetermined complex hollow metal structure to be diffuse bonded, polish and clean the surface of the complex hollow metal structure; Step 2: Place the complex hollow metal structure in a tooling mold for molding, and place the mold into a vacuum furnace; Step 3: Set up a dual-source control system; Step 4: Perform diffusion bonding under specified parameters, depressurize after the diffusion time is completed, and cool in the furnace until it reaches room temperature before removing the part. This invention combines pulsed DC heating and induction eddy current heating for diffusion bonding, improving diffusion efficiency while ensuring temperature uniformity, increasing the welding rate, and improving the quality of the diffusion joint.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Comprehensive simulation method for Brazilian disk splitting failure under dynamic and static actions

The invention discloses a comprehensive simulation method for splitting failure of a Brazilian disk under dynamic and static actions. The method comprises the following steps: establishing a Brazilian disk finite element model and defining material parameters; performing dispersion crack treatment on the model through a phase field variable and a crack density function; selecting a branch path according to a load type (static / dynamic); the static branch constructs an energy functional and a displacement-phase field control equation based on an F-M variation principle, and the dynamic branch deduces a dynamic control equation through a Lagrange energy functional and a Hamiltonian principle; a displacement field and a phase field are updated through finite element discretization and Newton-Raphson iteration solution; cyclic loading is judged through convergence until the load is applied, and finally the crack propagation process and the mechanical response are visually output. According to the method, integrated simulation of dynamic and static loads is realized through a unified phase field dispersion framework, the problem of model incompatibility in a traditional method is solved, and the crack propagation prediction precision is remarkably improved.
Owner:南昌轨道交通集团有限公司地铁项目管理分公司

A low-cycle multi-axial fatigue life prediction method based on powder high-temperature alloy damage mechanism

The present application relates to the technical field of high-temperature structural component fatigue strength design and life assessment, and particularly relates to a low-cycle multi-axial fatigue life prediction method based on powder high-temperature alloy damage mechanism. The method comprises: for the dangerous point of the component under non-isothermal multi-axial cyclic loading, calculating pure fatigue damage, pure creep damage and fatigue-creep interaction damage caused by a single load cycle; accumulating the pure fatigue damage, the pure creep damage and the fatigue-creep interaction damage to obtain the total damage of the single load cycle; taking the inverse of the total damage to predict the total failure life of the component under non-isothermal multi-axial cyclic loading. The method of the present application realizes effective prediction of the low-cycle multi-axial fatigue life of the powder high-temperature alloy component by accurately decomposing the damage of the dangerous point under non-isothermal multi-axial cyclic loading, can more truly reflect the comprehensive prediction model of the failure physics of the powder high-temperature alloy under multi-axial thermal mechanical loading, and improves the accuracy and reliability of the life assessment.
Owner:BEIJING UNIV OF TECH

A method and system for predicting creep fatigue behavior of martensitic heat-resistant steel

This invention discloses a method and system for predicting the creep fatigue behavior of martensitic heat-resistant steel, relating to the field of high-temperature creep fatigue performance evaluation technology. The method includes: acquiring the microstructure evolution of copper-containing martensitic heat-resistant steel during the test process, obtaining the cyclic strength change rate based on the microstructure evolution, and calculating the creep rate of the copper-containing martensitic heat-resistant steel in the dislocation climb hard phase, as well as the dislocation density under cyclic loading conditions; based on the cyclic strength change rate, creep rate, and dislocation density, obtaining the elastic strain tensor, plastic strain tensor, and creep strain tensor of the copper-containing martensitic heat-resistant steel, and predicting the stress-strain evolution of the copper-containing martensitic heat-resistant steel under cyclic loading conditions based on the elastic modulus tensor; this invention overcomes the limitations of macroscopic creep fatigue behavior prediction methods and provides a new approach to revealing the influence of microstructure on creep fatigue performance.
Owner:TIANJIN UNIV

An in-situ testing system for bearing capacity of surrounding rock of underground gas storage and a testing method thereof

The present application relates to the field of underground gas storage engineering test equipment, and specifically discloses an in-situ test system for bearing capacity of surrounding rock of underground gas storage and a test method thereof; an in-situ test hole is drilled and extended to the in-situ test hole of the original rock stress area on the side wall of the existing underground chamber or roadway, a loading assembly filled with high-pressure compressible gas and radially expanded is arranged at the bottom of the hole; a safety counterforce closed assembly including a pressure-bearing component, a force transmission component and an anchoring component is coaxially arranged in the hole, forming an axial counterforce continuous transmission path to limit axial displacement and reduce spouting instability; a stereoscopic monitoring system is formed by arranging monitoring holes and various sensors around the test hole, and stress, deformation, seepage and damage responses are collected; a loading and monitoring closed-loop control system dynamically adjusts the loading pressure, rate, pressure maintaining and cycle parameters according to the monitoring data, completes the graded / cyclic loading, and outputs the ultimate bearing capacity, fatigue bearing capacity index and operation pressure suggestion interval.
Owner:CHINA UNIV OF MINING & TECH +1

A pile cyclic load test device with adjustable bias cyclic force loading function

PendingCN122306596AMotor speedGear wheel
This invention discloses a pile cyclic load testing device with adjustable offset cyclic force loading function. The device includes a model box, a pile clamp, and an upper loading system. The upper loading system consists of a servo motor, an input shaft, a crank, a connecting rod, a rack, a gear, a gear shaft, a bidirectional torque limiter, a rack push rod, a buffer spring, an adjustable cantilever, a pulley, a loading cable, and loading weights. This invention allows for the adjustment of the torque limiter threshold, the weight mass, and the servo motor speed to achieve cyclic loads of different amplitudes, offset degrees, and frequencies. The mechanical transmission structure avoids frequent motor reversals, improving test stability and device lifespan. This device is suitable for studying the dynamic response of piles under cyclic loading conditions such as wind, waves, vehicle loads, and mechanical vibrations, providing a reliable testing method for pile foundation design and dynamic performance evaluation.
Owner:POWERCHINA HUADONG ENG CORP LTD

A fatigue design method for high-strength bolts used in aircraft wheels

PendingCN122310701AAviationControl theory
This application discloses a fatigue design method for high-strength bolts used in aircraft wheels, specifically relating to the field of aircraft components. The method includes: determining the bolt preload and preload torque based on the bolt's nominal diameter, the bolt material's yield strength, and a first preset relationship, combined with the bolt's application environment; determining the minimum and maximum stresses on a single bolt; determining the stress cycle ratio of a single bolt; when the stress cycle ratio reaches a preset value, determining the equivalent stress based on the minimum and maximum stresses on a single bolt; determining the bolt's cycle life based on the equivalent stress, and combining the product of the tire's rolling circumference and the aircraft's takeoff and landing distance to determine the bolt's takeoff and landing life. Based on the above method, the service life of high-strength bolts under fatigue cyclic loading can be improved.
Owner:XIAN AVIATION BRAKE TECH

Method for predicting dynamic fatigue life of fused salt storage tank

The invention discloses a method for predicting the dynamic fatigue life of a fused salt storage tank. The method can be used for simulating the stress and deformation conditions of the fused salt storage tank in the heat charging and discharging process and analyzing and predicting the fatigue life. The invention relates to the technical field of adiabatic compressed air energy storage, in particular to a dynamic fatigue life prediction method for a fused salt storage tank in a heat storage subsystem. According to the method, through finite element modeling, dynamic fluid-solid coupling simulation and cyclic loading calculation and in combination with the fatigue life prediction theory, the structural weak area of the tank body in the dynamic process is determined, and a theoretical basis is provided for structural optimization of the tank body. According to the invention, the stress-strain dynamic distribution rule of the fused salt storage tank in the salt charging and discharging process can be comprehensively simulated, so that the fatigue life of the storage tank under the cyclic load effect can be predicted, and the test cost can be saved for the structural optimization of the storage tank.
Owner:POWERCHINA HUADONG ENG CORP LTD

Saturated sand dynamic constitutive model construction method considering pore pressure fluctuation increase

The invention relates to a saturated sand dynamic constitutive model construction method considering pore pressure fluctuation growth, which comprises the following steps: determining total pore water pressure including residual pore pressure component and transient pore pressure component, and constructing a normalized stress ratio skeleton curve independent of a pore pressure state; correcting the total pore water pressure to obtain corrected pore water pressure, and updating the average effective stress at the current moment by using the corrected pore water pressure; coupling the normalized stress ratio skeleton curve and the updated average effective stress to obtain a maximum shear stress value; the maximum shear stress value is used as a target state point, a dynamic virtual hysteretic curve is constructed, the stress-strain behavior of saturated sandy soil is described, accumulated damage and alternate shear shrinkage-shear expansion effects of a soil body in the cyclic loading process can be effectively considered, a pore pressure development curve and cyclic shear stress-strain response which better conform to the test rule are captured, and the test accuracy is improved. And a valuable tool is provided for evaluating the response and liquefaction strength of the saturated sand under the undrained cyclic loading condition.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Method, device and electronic equipment for predicting fatigue life of a gfrp-rc beam

The present application relates to a kind of method, device and electronic equipment for predicting GFRP-RC beam fatigue life, method includes: obtaining the limit bearing capacity before the destruction of GFRP-RC beam and the maximum deflection before the destruction of the GFRP-RC beam, the limit bearing capacity and the maximum deflection are by the GFRP-RC beam is obtained by three-point bending static loading test, obtain the initial fatigue deflection value of the GFRP-RC beam, the initial fatigue deflection value is by the GFRP-RC beam is carried out fatigue stress level cyclic loading test, and the test result is carried out initial deflection identification and obtains, based on the maximum deflection and the initial fatigue deflection value, input to the preset CEB-FIP fatigue life prediction model, obtain the GFRP-RC beam fatigue life.
Owner:HUBEI JIAOTONG EXPRESSWAY CONSTR MANAGEMENT CO LTD +5

Alloy cable tensile strength testing method and system

The invention discloses an alloy cable tensile strength test method and system, and relates to the technical field of cable test.Through continuous execution of steps S1 to S4, under the condition that existing tensile machine hardware conditions are not changed, a baseline output set Out1 can be established, a cyclic output set Out2 can be obtained through cyclic loading, and a final strength set Ufn can be measured after fatigue action; compared with an existing mode which only depends on a single static tensile strength test, the method has the advantages that the strength attenuation law of the alloy cable under the low-amplitude cyclic loading effect can be directly quantified, a strength judgment result which is closer to a long-term service condition is provided, and the fatigue coupling coefficient Fec is obtained through calculation. Not only is the defect that the traditional test cannot simulate strength degradation in practical application solved, but also the residual service capability of the alloy cable is clearly revealed through the fatigue coupling coefficient Fec, so that a scientific and reliable strength evaluation basis is provided for engineering application.
Owner:SHENZHEN SHENZHOU CABLE

Damping steel tensile test method

The invention provides a damping steel tensile test method, which relates to the technical field of metal material performance detection, and comprises the following steps: a testing machine adopts automatic program control, the initial tensile speed is set to be 1-5mm / min, a displacement control mode is adopted, hysteresis loop method cyclic tensile is performed for the first time, the target strain point of a first extensometer is set to be 1%, and the target strain point of a second extensometer is set to be 1%; the lower reverse point of the lag loop is 5-10 MPa, and the load holding time is 10-20 s; the strain is accumulated in sequence, the target strain point of the extensometer in each cyclic stretching is increased by 1%, the stress is unloaded to 5-10 MPa after the target strain point is reached each time, and loading is carried out again after the load is kept for 10-20 s until the sample is fractured; extracting stress-strain original data of each time of cyclic stretching, and performing data superposition on the original data extracted each time to form a stress-strain curve of cyclic stretching; and according to the stress-strain curve, analyzing the mechanical property and damping property change of the damping steel under cyclic loading.
Owner:ANGANG STEEL CO LTD

420 MPa-grade wind power steel welded joint with fatigue grade of DC112 and preparation method of 420 MPa-grade wind power steel welded joint

The invention belongs to the technical field of metallurgy, and particularly relates to a 420 MPa-grade wind power steel welded joint with the fatigue grade of DC112 and a preparation method. According to the 420 MPa grade wind power steel welded joint, under the tension-tension fatigue test condition that the stress ratio R is equal to 0.5, after 2 * 106 times of cyclic loading, the fatigue strength of the 420 MPa grade wind power steel welded joint reaches 112 MPa, and the strict requirement for the DC112 grade fatigue grade in the international standard DNV-ST-0126 is completely met. The performance index is obviously superior to the prior art level, and key technical support is provided for high-reliability design and light-weight manufacturing of a wind power tower tube structure.
Owner:YANSHAN UNIV +2

A method for rapid prediction of thermal-mechanical fatigue life of metal materials based on hysteretic energy density

The present application relates to the field of material science and engineering application technology, specifically to a kind of metal material thermal mechanical fatigue life fast prediction method based on hysteresis energy density.First, hysteresis curve is used to calculate hysteresis energy density, then the quantitative relationship between shape coefficient, stress variation range and plastic strain range between low cycle fatigue and thermal mechanical fatigue is used, to achieve the purpose of predicting thermal mechanical fatigue hysteresis energy density under the same mechanical strain amplitude by low cycle fatigue, finally, energy accumulation damage model is used to predict thermal mechanical fatigue life.The method carries out two groups of experiments for low cycle fatigue and thermal mechanical fatigue respectively, realizes the prediction of thermal mechanical fatigue life under different mechanical strain amplitudes by low cycle fatigue, establishes the correlation between low cycle fatigue and thermal mechanical fatigue by using the similarity between them in the process of cyclic loading, effectively reduces the experimental amount required for thermal mechanical fatigue life evaluation, and is applied to the thermal mechanical fatigue life prediction of high-temperature alloy and vermicular cast iron and other metal materials.
Owner:INST OF METAL RESEARCH - CHINESE ACAD OF SCI

Damage detection device for steel angle main material of power transmission tower

The invention discloses a damage detection device for an angle steel main material of a power transmission tower, and relates to a damage detection device. The invention aims to solve the problems of low detection efficiency, high cost and high omission ratio when the existing angle steel main material is detected. A magnetic conductivity probe, an ultrasonic flaw detection probe and a pressure sensor are integrated to cooperatively work to form a three-dimensional detection system of surface stress detection, internal flaw detection and pressure calibration; the magnetic conductivity probe detects stress distribution of an angle steel main material through an inverse magnetostrictive effect, and accurately identifies a local strain high-risk area under a cyclic load; early warning is provided for fatigue crack initiation; the ultrasonic flaw detection probe penetrates through the metal surface by using high-frequency sound waves to carry out deep scanning on a high-risk area and detect defects such as internal cracks and air holes, so that full-dimensional damage identification from the surface to the inside is realized; the pressure sensor calibrates the attaching state, and it is ensured that the attaching pressure of the magnetic conductivity probe and the measured surface is consistent. The invention belongs to the technical field of electric iron tower damage detection.
Owner:HEILONGJIANG ELECTRIC POWER SCIENCE RESEARCH INSTITUTE +1

Method for evaluating pore pressure of saturated sand based on permeability of weak permeable interlayer

The invention belongs to the technical field of saturated sandy soil dynamic analysis, and particularly relates to a saturated sandy soil pore pressure evaluation method based on weak permeable interlayer permeability. Establishing a layered model composed of saturated sand and the weak permeable interlayer; selecting a dynamic constitutive model suitable for cyclic loading conditions; applying a self-weight load to the dynamic constitutive model to generate an initial stress field of the dynamic constitutive model; based on a finite difference theory, constructing a dynamic fluid-solid coupling analysis model of a saturated sand dynamic response control equation and a pore water seepage control equation; simulating pore water pressure response of the saturated sandy soil under different power working conditions; and quantitatively evaluating the influence of the permeability of the weakly permeable interlayer on the pore pressure accumulation, dissipation and liquefaction response of the saturated sand. According to the method, the dynamic numerical model considering the interlayer permeation difference is established, and the influence of the weakly permeable interlayer on the pore water pressure generation, diffusion and dissipation process is systematically analyzed, so that the pore pressure response of the saturated sand is accurately evaluated.
Owner:JIANGSU UNIV

Concrete asymmetric fatigue test system and method based on ultrasonic vibration loading

The application discloses a kind of concrete asymmetric fatigue test systems based on ultrasonic vibration loading, including universal testing machine, ultrasonic frequency generator, ultrasonic transducer, upper displacement amplifier and lower displacement amplifier and for reducing system loading eccentric moment ball hinge mechanism, the ball hinge mechanism is connected with lower displacement amplifier bottom by clamping connecting disc.This application also provides a kind of concrete asymmetric fatigue test method based on ultrasonic vibration loading, fix the concrete test piece of equal cross section cylinder between upper displacement amplifier and lower displacement amplifier, then open universal testing machine, ultrasonic frequency generator and ultrasonic transducer, realize the ultrasonic vibration asymmetric compression-compression fatigue cycle loading of concrete test piece.The application can realize the asymmetric compression-compression fatigue loading of concrete test piece by ultrasonic fatigue test technology, solve the problem of high time cost in the super-long life fatigue test of traditional concrete fatigue test system.
Owner:SICHUAN UNIV

An Electrically Assisted Tension-Compression Cyclic Loading Device and Testing Method for Ultra-Thin Titanium Plates

The present invention discloses an electro-assisted tension-compression cyclic loading device and testing method for ultra-thin titanium plates. The device comprises a composite tension-compression specimen, wherein a lateral force is applied to both sides of the composite tension-compression specimen; two pairs of electro-assisted fixtures, respectively clamping both ends of the composite tension-compression specimen, include two oppositely arranged clamping heads. The clamping surface of the clamping heads have a conductive structure, and the conductive structure is connected to an external power source, so that when the composite tension-compression specimen is clamped on the clamping head, the conductive structure contacts the composite tension-compression specimen to transfer current to the composite tension-compression specimen through the conductive structure to heat it. The clamping head is further connected to the loading end of a universal testing machine. The present invention can avoid torsional deformation of the ultra-thin titanium plate specimen during the test.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Simulation analysis method and equipment for rigidity and strength fatigue wear of clutch separation device and medium

The invention provides a rigidity and strength fatigue wear simulation analysis method and equipment for a clutch separation device and a medium, and belongs to the technical field of vehicle clutches. Three-dimensional models of a separation shifting fork shaft, a rocker arm and a gearbox front shell are obtained, and a finite element model is established based on the three-dimensional models; defining a constraint set point, a surface grid set, a contact relation, a material attribute and a grid type; and applying a first load to the surface grid set to establish pre-contact, and then applying a second load to perform static simulation. Extracting stress data to determine a dangerous position, and extracting displacement data to calculate torsional rigidity. And based on the dangerous position and second load cyclic loading, fatigue safety coefficient distribution is obtained, and bushing wear data are extracted to evaluate the wear condition. The rigidity, the fatigue life and the lining abrasion performance of the separation device are evaluated synchronously through simulation, a stress danger area and an abrasion overrun area are positioned, data support is provided for structural optimization and maintenance period formulation, the reliability of the clutch is improved, and the service life of the clutch is prolonged.
Owner:SINO TRUK JINAN POWER CO LTD

Anti-fatigue pressure-sensitive adhesive and preparation method thereof

The application belongs to the field of pressure-sensitive adhesive bonding materials, and discloses an anti-fatigue pressure-sensitive adhesive, which comprises a first adhesive layer, a structural layer and a second adhesive layer in sequence, and the structural layer comprises a plurality of structural units arranged at intervals. Through the above structural design, the anti-fatigue pressure-sensitive adhesive provided by the application can form a bridging energy dissipation zone under the action of cyclic loading or static sustained loading, thereby inhibiting crack propagation and improving the interface anti-fatigue performance and service life; the structure is suitable for various pressure-sensitive adhesive tape systems and can be applied to different substrate surfaces, and has good material applicability and commercial application prospect.
Owner:ZHEJIANG UNIV

Method for determining the operating pressure of a compressed air energy storage cavern

The application discloses a kind of compressed air energy storage cavern operating pressure determination method, comprising the following steps: establishing the elastic mechanics plane strain model of surrounding rock-lining-sealing layer composite structure, deducing the analytical solution of elastic stress and displacement of composite structure;Determine the upper limit of cyclic internal pressure;Introduce the spatial heterogeneity function of surrounding rock parameter, deduce the elastoplastic stress and plastic zone radius expression of composite structure;Introduce the fatigue damage evolution equation to correct rock mass strength parameter, based on the plastic zone radius control condition, solve lower limit pressure.The method can simultaneously utilize initial geostress to constrain surrounding rock deformation and quantify the attenuation of rock mass parameters caused by long-term cyclic loading, while ensuring that surrounding rock does not produce tensile failure and the expansion of plastic zone is controllable, the best operating pressure range and amplitude of compressed air energy storage cavern in the whole life cycle of up to 30 years are accurately quantified, so as to ensure the long-term sealing and safety of the structure, effectively optimize the design parameters, and improve the engineering economy.
Owner:CHINA RAILWAY FIRST SURVEY & DESIGN INST GRP +1

A composite material fatigue performance prediction method and system based on infrared thermal imaging

PendingCN122282529AAccelerate research and developmentSpeed ​​up the selection processFatigue loadingStress level
This application provides a method and system for predicting the fatigue performance of composite materials based on infrared thermal imaging, belonging to the field of material mechanical property testing technology. The method includes determining the fatigue performance characterization parameters and corresponding static strength values ​​of the composite material to be predicted; constructing a fatigue performance testing system for the composite material; determining the progressively increasing fatigue loading stress and load; applying progressively increasing stress levels of fatigue cyclic loading to the composite material under a given cycle to obtain a temperature field sequence and extracting temperature characteristic parameters characterizing the material's energy dissipation state; based on the temperature characteristic parameters and a composite material damage infrared characteristic library, obtaining the temperature-damage characteristic-stress relationship of the composite material under each cyclic loading level; based on this relationship, obtaining the critical transformation stress of the composite material to be predicted, determining the fatigue limit, and obtaining the fatigue life-stress relationship for fatigue performance prediction. This scheme improves prediction efficiency and accuracy, and avoids misjudgment based on a single parameter.
Owner:CHINA AIRPLANT STRENGTH RES INST