35 results about "Cyclic loading" patented technology

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.

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.

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.

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.

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.

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.

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.

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.

This invention relates to a method for evaluating service damage of aero-engine compressor blades, solving the problem that current blade performance testing cannot obtain test values ​​'d' through direct sampling from the blade. The method comprises the following steps: S1: Design the dimensions of the blade simulator; S2: Select a base material consistent with the blade; S3: Calculate the maximum temperature and maximum stress of the blade under different service conditions, based on the blade's design status; S4: Statistically count the number of Category I low-cycle cycles, Category III flight takeoff cycles, and Category IV powered takeoff cycles for at least 10 engines, and calculate the conversion factors for each type of cycle using the temperature and stress calculation values ​​under different service conditions to obtain the equivalent number of cycles for different service times; S5: Apply low-cycle fatigue loading, fixing and clamping the simulator, and performing low-cycle cyclic loading according to the stated temperature, stress, and number of cycles; S6: Take samples from the low-cycle fatigue-treated specimen and perform tensile and high-cycle fatigue mechanical property tests. This invention significantly reduces the need for collecting blade service conditions and parameters, greatly reducing workload.

This invention relates to the field of logistics transportation scheduling and loading optimization technology, and discloses a robust two-stage cyclic pickup loading and route optimization method and system, including: acquiring planned data and real-time status data; based on the planned data, solving a preset planned stage model to generate a master plan; in the execution stage, based on the real-time status data, performing execution verification on the master plan; when the verification finds that packing is infeasible or results in a late return to the factory, triggering the solution of a preset minimum repair model to generate an executable repair solution; outputting the repair solution or the verified feasible master plan as the final scheduling solution. This invention significantly improves the execution reliability and economy of the cyclic pickup scheme by constructing a two-stage collaborative optimization closed loop of planning and execution, simultaneously integrating three-dimensional packing feasibility verification, opportunity cost quantification of reserved buffer space, and timeliness control based on robust optimization in route planning.

The application discloses a kind of multi-scale modeling and fracture simulation method for compressed air energy storage cover layer integrity evaluation, steps include: constructing multi-scale heterogeneous geomechanics model;Establish the fatigue damage constitutive relationship under rock loading and unloading condition;Establish fracture simulation control equation;Multi-scale calculation strategy and local adaptive grid are constructed;Cyclic loading condition simulation and integrity quantitative evaluation are carried out.The application is designed for the core damage mode of CAES gas storage low pressure fatigue, compared with general structure analysis software, the pertinence and accuracy of cover layer integrity evaluation are higher, the heterogeneous geological characteristics of cover layer are truly reflected, the process of crack initiation and propagation in cover layer under cyclic injection and production conditions is accurately simulated, and the advanced prediction and quantitative evaluation of cover layer integrity failure risk are realized.

The application discloses a vertical cyclic loading test system applied to a geotechnical centrifuge and a control method, which comprises a model box, a counterforce mechanism, a vertical loading mechanism and an electrical control mechanism, the counterforce mechanism is fixed on the top of the model box, the vertical loading mechanism is vertically installed on the counterforce mechanism, and the vertical and horizontal position of the vertical loading mechanism on the counterforce mechanism is adjustable, the application can stably work under a high centrifugal acceleration of 160g, the maximum loading force reaches 400kN, the control precision is 0.2kN, the maximum displacement stroke is 160mm, the displacement precision is 0.1mm, the cyclic loading frequency is 1Hz, and the cyclic amplitude is ±30mm, so that the simulation requirement of most high bearing capacity working conditions of marine engineering, pile foundation engineering and the like can be met.

The application discloses a four-element model of concrete modulus and creep under long-period cyclic loading and a parameter determination method thereof. The model simulates the behavior of concrete under long-period cyclic loading through four series mechanical elements, including an instantaneous elastic deformation element with time-increasing stiffness, a recoverable creep viscoelastic element, an unrecoverable compression creep element and an unrecoverable tension creep element. In order to overcome the difficulty of small sample amount of the application object, the method adopts a step-by-step mode to classify and stage the parameter calibration of the concrete modulus and creep model.

Method for testing an assembly (2) for an electrical machine, in particular a separately excited synchronous machine, comprising two electrical conductor elements (3, 4) which are connected to each other by a crimp connection (5), wherein the crimp connection (5) is subjected to cyclic loading, in particular by applying a test force to one of the conductor elements (3, 4), and wherein a connection parameter of the crimp connection (5) is determined.

This invention relates to a method for calculating rock fatigue damage under constant amplitude increasing average stress, comprising the following steps: designing loading parameters and calculating rock fatigue damage variables defined by residual strain; establishing a nonlinear fatigue damage evolution model for constant amplitude and continuously increasing average stress; fitting the data of rock fatigue damage variables defined by residual strain as a function of the number of cycles to the nonlinear fatigue damage evolution model to obtain coefficients; fitting each coefficient to the loading parameters to obtain the relationship between each coefficient and the loading parameters; substituting the relationship of the loading parameters into the nonlinear fatigue damage evolution model to obtain a fatigue damage evolution model of lithological rock under cyclic loading with a constant amplitude linearly increasing average stress, calculating rock fatigue damage under constant amplitude increasing average stress, and predicting the evolution characteristics of rock fatigue damage. This invention can reduce the number of cyclic loading experiments and the cost, and can accurately describe the evolution of rock damage variables.

This invention discloses a test apparatus for the ultimate strength of a ship hull beam section under cyclic loading, comprising a specimen, a gantry system, and an actuation device. The specimen includes a test section, an extension section, a lengthening section, supporting steel columns, and loading steel columns. Extension sections are welded to both ends of the test section, and the extension sections are fixedly connected to the lengthening sections. Loading steel columns are welded to both ends of the top and bottom surfaces of the test section. Supporting steel columns are welded to the ends of the lengthening sections. Support supports are fixedly installed at both ends of the gantry system, and the support supports have openings for the supporting steel columns to pass through at both ends, allowing the loading steel columns to slide freely along the ship's length. The actuation device includes an upper actuating head installed above the test section and a lower actuating head installed below the test section. This invention can simultaneously apply mid-sag / mid-camber loads to the test section of the ship hull beam while ensuring that the test section only bears pure bending moments and not shear stresses, thus obtaining the ultimate strength of the test section of the ship hull beam under cyclic loading of mid-sag / mid-camber.

The present application relates to the technical field of automobile parts testing, and particularly relates to a cyclic load fatigue testing device for a suspension rubber bushing, which comprises an outer cylinder clamp, an inner cylinder limiting mechanism, a multi-axis guiding mechanism and a load simulation mechanism. The inner cylinder limiting mechanism constrains the radial translation of the bushing inner cylinder and retains the rotational freedom through a mandrel and a fixed shaft support; the multi-axis guiding mechanism guides the outer cylinder clamp to reciprocate in at least two mutually perpendicular radial directions. The load simulation mechanism simultaneously links a radial driving unit and a torsional driving unit through a main drive shaft, and utilizes the one-way rotation of the main drive shaft to synchronously drive the radial displacement of the outer cylinder clamp and the axial rotation of the mandrel. The present application adopts a full-mechanical hard-link transmission architecture, ensures the absolute phase synchronization of the radial translation load and the axial torsional load on the time axis, can truly restore the fatigue failure process of the bushing under a multi-dimensional composite stress state, and has the remarkable advantages of high simulation accuracy, good testing repeatability and the like.

The present application relates to the field of structural fatigue fracture prediction and computational fracture mechanics, and particularly relates to a high-temperature notched fracture phase field life prediction method based on cyclic plastic zone calibration. In view of the fact that significant viscoplastic flow occurs at the root of the notch under high-temperature cyclic loading, and the fact that the value of the characteristic scale parameter in the existing fatigue phase field model lacks physical basis, leading to high sensitivity of life prediction to parameters, the method obtains the local stress-strain response at the root of the notch based on a unified viscoplastic cyclic constitutive model, quantifies the characteristic size of the inelastic process zone at the root of the notch by using the cyclic plastic zone theory, and establishes a quantitative mapping between the characteristic size and the regularization length of the fracture phase field to determine the characteristic scale of the phase field; in the finite element framework, the alternating iterative solution of the displacement field and the phase field variables is realized by coupling the UMAT and UEL user subroutines, so that the crack initiation, propagation and branching can be simulated without presetting the crack path, and the crack evolution process and fatigue life prediction results of the notched component under high-temperature working conditions are output.

A method for intelligent monitoring and failure evaluation of cement sheath characteristic parameters in hydrogen storage wells under high-frequency cyclic injection and production is characterized by the following steps: First, the method uses full-scale experiments and distributed fiber optic sensing technology to collect strain and acoustic emission signals of the cement sheath under cyclic loading and hydrogen environment in real time, and extracts key characteristic parameters such as cumulative acoustic emission energy, strain energy density, and distribution non-uniformity index. Then, a quantitative prediction model between the aforementioned fiber optic characteristic parameters and cement sheath characteristic parameters is established using multivariate nonlinear regression analysis. Finally, the model is integrated with preset failure criteria to construct an intelligent evaluation system, enabling online, quantitative evaluation and early warning of cement sheath health status driven by real-time data. This invention overcomes the limitations of traditional static evaluation, accurately identifies failure modes, and provides key technical support for the safe operation of hydrogen storage wells. This invention is applicable to the field of oil and gas drilling and production engineering technology.

The present application relates to the field of civil engineering material simulation technology, and provides a kind of track slab SCC multi-phase mesoscopic fatigue damage near-field dynamics simulation method, comprising: according to four-point bending fatigue test to establish two-dimensional mesoscopic near-field dynamics model;Meshless discretization is carried out to the model;Define the material parameters of cement mortar, coarse aggregate and interface transition zone;Set boundary conditions;Random polygon aggregate is generated by taking and placing method to simulate mesoscopic heterogeneous structure;Mark particle and key type;Apply cyclic loading;Damage evolution calculation is carried out based on the maximum key elongation criterion and fatigue life model;Finally, the calculation is terminated by particle damage index judgment.The present application can realize the accurate simulation of the whole process from crack initiation to expansion of CRTS III type track slab self-compacting concrete, provide effective numerical analysis tool for revealing the influence mechanism of aggregate distribution randomness on fatigue performance, and thus provide theoretical basis for track structure durability design and maintenance.

The application discloses a kind of based on heat dissipation's ultra-high cycle fatigue stress life curve evaluation method.This method is loaded by stepwise increment fatigue stress amplitude to single sample, until the sample breaks;Real-time monitoring test sample surface temperature rise under different stress amplitude and corresponding cycle loading cycle;By analyzing the heat dissipation of single sample under different stress amplitude, the fatigue life limit under each stress amplitude is calculated, and the complete stress life curve is constructed.The number of fatigue test samples is greatly reduced, the ultra-high cycle fatigue stress life curve of the material is quickly obtained, the experimental cost is effectively reduced, and reliable data support is provided for material design and service safety evaluation.

This utility model belongs to the field of offshore wind power and discloses an integrated experimental device for fatigue testing and displacement monitoring of offshore wind turbine suction cylinder jacket foundations. It includes a support frame and a sandbox. The support frame is equipped with a cyclic loading mechanism, a displacement measuring mechanism, and a unidirectional loading mechanism. The sandbox is used to place the suction cylinder jacket foundation. The cyclic loading mechanism is connected to the tower and includes an actuator, a floating joint, and a tension sensor connected in sequence. The displacement measuring mechanism detects the displacement of the tower. The unidirectional loading mechanism includes a loading rope and a loading counterweight. One end of the loading rope is connected to the tower, and the other end is connected to the loading counterweight. This utility model integrates cyclic loading, unidirectional loading, and displacement monitoring on the same platform, realizing synchronous loading and real-time measurement of the fatigue response and foundation tilting process of the suction cylinder jacket, improving experimental efficiency and data consistency.

The application discloses a yield strength correction calculation method for instrumented indentation method, which comprises the following steps: a target material is subjected to cyclic loading test by using an instrumented indentation tester to obtain a load-displacement curve, and true stress and true strain are obtained by the load-displacement curve, and the true stress and true strain measuring points have all entered a plastic hardening stage, and the yield strength cannot be accurately extrapolated. The instrumented indentation method can very accurately obtain the tensile strength, and it can be considered that no matter whether there is a yield platform, the constitutive curve of the plastic hardening stage of the material constitutive relation remains unchanged, that is, the strengthening coefficient K and the strain hardening index n obtained by fitting the Holloman equation in this part remain unchanged, and due to the existence of the yield platform, the plastic hardening stage of the constitutive curve is translated as a whole to obtain a new constitutive equation, and the influence of the yield platform can be considered. The application improves the precision of the instrumented indentation method in on-site detection of the yield strength of steel structure materials.

The present application belongs to the field of laser additive manufacturing and remanufacturing technology, and relates to a laser additive manufacturing and remanufacturing high-temperature alloy component life prediction method and device. The alloy component manufactured and remanufactured by laser is obtained, and a standard sample is cut on the alloy component. Defect scanning is respectively performed on the alloy component and the standard sample to obtain pore defect characteristics. Fatigue tests are respectively performed on the alloy component and the standard sample to obtain S-N curves. A phase field model of the alloy component is constructed, the pore defect characteristics of the alloy component are introduced into the phase field model, and then cyclic loading is applied for fatigue evolution simulation, so that a fatigue life prediction model considering laser additive manufacturing and remanufacturing induced pore defects is obtained. The pore defect characteristics of the standard sample and the S-N curve are used for W-N f curve fitting, parameter calibration is performed on the fatigue life prediction model, and a target fatigue life prediction model is obtained. The target fatigue life prediction model is used for fatigue life prediction and crack evolution of the alloy component.

The present application belongs to the technical field of rotor dynamics, and discloses a rotor system dynamics analysis method containing blade rub. The traversal cycle loading mode is used to simulate the rotor unbalance effect, the rotation of the blade is simulated, the vibration displacement of the blade tip node and the vibration displacement of the blade root node are calculated after the centrifugal deformation of the blade is calculated separately, the difference is calculated to obtain the blade deformation, the blade deformation coordinates are converted, the position vector of the disc and the position vector of the rotating shaft are superposed, the blade tip intrusion amount after coating wear is calculated, and the normal rub force vector of the multi-blade is constructed. Then, the beam element, the shell element and the solid element are used to construct the rotor system dynamics model containing blade rub under the motor flight condition, wherein the nonlinear force model is used to calculate the bearing to consider the influence of the nonlinearity on the rub behavior; the dynamics calculation is carried out through the reduction of the degree of freedom and the interface separation, and finally the rub dynamics response of the system is calculated through the numerical simulation analysis, and the influence of the motor analysis on the rub characteristics is analyzed.