32results about How to "Predict fatigue life" patented technology

The invention discloses a steel bridge fatigue evaluation load modeling and fatigue evaluating method. The steel bridge fatigue evaluation load modeling and fatigue evaluating method comprises, step one, establishing a train load model; step two, processing and classifying measured data; step three, according to the measured data, establishing a probability model for parameters; step four, establishing a train load probability model; step five, generating a random load spectrum through a Monte-Carlo method; step six, through finite element analysis, acquiring stress influence lines of steel bridge fatigue details; step seven, performing influence line loading through the random load spectrum to obtain a stress history; step eight, analyzing the stress history to evaluate steel bridge fatigue. The steel bridge fatigue evaluation load modeling and fatigue evaluating method has the advantages of, through the fatigue evaluation load model which is established on the basis of the measured data for describing the load status of currently-running trains, achieving fatigue evaluation of any component of a steel bridge, establishing a complete train load modeling method, improving the utilization value of the measured data and ensuring more accurate and more practical steel bridge fatigue evaluation.

The invention proposes a cubic press health monitoring method and system. The monitoring system comprises a power management module, a signal processing module and a remote control monitoring module which are serially connected. The signal processing module comprises a strain detection module, a signal conditioning module, a microprocessor, a storage module and a wireless data transmission module; the strain detection module comprises a strain collection sheet, a bridge-type compensation circuit, and an electronic switch; the signal conditioning module comprises a passage amplifier, a filter and an A / D converter; The remote control monitoring module is arranged in a remote monitoring room and acquires the test data through the wireless data transmission module. The aim of online health monitoring of cubic presses is achieved based on an electrical strain measuring method and modern wireless transmission technology. The cubic press health monitoring system can accurately acquire weak strain signal data, has the functions of online monitoring and real-time display and recording of equipment usage status, and can predicate the fatigue life of equipment in actual work conditions, thereby preventing great and malignant accidents and reducing losses.

This invention relates to one rack electricity sending circuit online monitor system and method, which process online test on rack circuit micro wind vibration and wire temperature and bias wind and comprises data monitor device, base station and monitor supportive system, wherein, the data monitor device is in rack send circuit sent to base station through short distance sensor network broadcasting; base station receives the data to send to monitor supportive system center station through mobile communication network; the center station receives the network sending information to fulfill tasks of circuit micro wind vibration and wire temperature testing.

The invention discloses a prediction method of metal material multiaxial high cycle fatigue failure including mean stress effect; the prediction method of metal material multiaxial high cycle fatigue failure including mean stress effect comprises the following steps: using the uniaxial fatigue and the pure torsional fatigue as the boundary conditions for calculating the biggest damage surface born by the material during the fatigue loading process and taking the biggest damage surface as the boundary surface, selecting the positive stress and the shearing stress on the boundary surface as the damage parameter, using the mean stress effect parameter obtained by the uniaxial fatigue for correnting the stress on the boundary surface, and establishing the metal material multiaxial high cycle fatigue failure prediction model including axial direction mean stress and shearing stress influence; the prediction method of metal material multiaxial high cycle fatigue failure including mean stress effect is also applied to the situation without axial mean stress and shearing mean stress. The fatigue service life, the fatigue crack initiation and the initial extension direction of the material under multiaxial high cycle fatigue loading situation can be precisely forecasted while the axial mean stress and shearing mean stress are present.

The invention discloses a metal structure fatigue crack expansion life prediction method based on Taylor perturbation series method, and the method comprises the steps of first describing fatigue crack expansion process of the metal structure by employing Paris formula; conducting integration to the Paris formula to obtain an integration-formed crack expansion equation; and conducting Taylor expansion to the crack expansion equation. Then considering apparatus measuring error and structure manufacturing error to make an initial crack length contain a small disturbance; expressing the solution of the crack expansion equation and the initial crack length in perturbation grades by introducing a small parameter Epsilon; determining the perturbation grades according to an nominal value of the initial crack length and the disturbance so as to get the value of each coefficient at an initial time; obtaining a crack expansion perturbation equation in combination with the Taylor expansion of the crack expansion equation based on parameter perturbation theory; then solving the perturbation equation to obtain a fatigue crack expansion length perturbation grades solution; calculating load cycle times when a critical crack length is reached; and taking the load cycle times as a predicted value of the metal structure fatigue crack expansion life.

The invention discloses a vehicle body stress testing device for a high speed train and a work method thereof. The test apparatus comprises a strain sensor, a temperature sensor, a controller, a data collector, a switch, a remote server and a near-end debugging machine, wherein the strain sensor and the temperature sensor are connected with the data collector through an armored optical cable, and the data collector and the controller are connected through a net cable for instruction and data transmission. A fiber grating sensor measures stress, and fiber can effectively overcomes the defects of poor anti-electromagnetic interference capability in a conventional electric test method. Accurate stress signal can be obtained under complex electromagnetic environment of a high-speed rail, and subsequent data processing s more convenient. For each channel of a data collector, a plurality of fiber grating sensors of a same type can be serially connected through one fiber wire, the wiring difficult is lowered, and the space of train equipment cabin can be saved. The vehicle body stress testing device and the working method thereof can be used for researching vehicle body stress gradually changing trend under different line conditions.

The embodiment of the present disclosure discloses a method for analyzing the fatigue life of a spring. The method includes: establishing a stress-cumulative action number curve; obtaining a stress-life curve of the spring material to be tested; and obtaining each of the cumulative actions according to the stress-life curve Standard stress data corresponding to the number of times; establish the stress correspondence relationship between the standard stress data and the test stress data; obtain the ultimate stress corresponding to the ultimate life of the spring material to be tested on the stress-life curve; based on the stress correspondence, obtain the limit The limit test stress corresponding to the stress; based on the limit test stress and the stress-cumulative action times curve, predict the limit test life, and use the limit test life as the fatigue life of the spring to be tested. The technical solution can truly reflect the fatigue life of the spring in the actual use environment, so that the engineering personnel can learn the potential safety hazards in time and avoid equipment damage.

The invention discloses a method for evaluating the asphalt mastic fatigue performance. The asphalt cement and aggregates are formed and are made into asphalt mastic test pieces; the asphalt mastic fatigue performance is evaluated through the crack expansion index delta R(N) in the given load circulation times N of the asphalt mastic test pieces. The method provided by the invention is combined with an asphalt and aggregate surface free energy test and dynamic mechanical analysis experiment method; the area defined by a stress-pseudo strain curve is used for expressing the energy dissipation after the damage of the fatigue test pieces; in addition, the time effect can be eliminated; the asphalt mastic fatigue performance is evaluated; the fatigue service life of the asphalt mastic and asphalt mixture is predicted. Compared with other fatigue tests, the test method provided by the invention has the advantages that the test investment is low; the test period is short; the practical stress state of the pavement can be represented under the dynamic load.

The invention provides a fatigue test device and test method for the main force transmission structure during the ejection process of the landing gear. The force device fixing mechanism; the test method mainly includes the following steps: (1) installation and fixing of the test piece; (2) installation and fixing of the ejection loading device mechanism; (3) installation and fixing of the restraining loading device mechanism; (4) cyclic loading test; (5) Residual strength test for the maximum ejection force condition. The invention measures the fatigue life of the main force transmission structure; adopts the hydraulic cylinder to load, the load is stable and the continuity is good; the layout and installation of the test device can accurately simulate the real working conditions of the main force transmission structure, and at the same time, the construction and installation are simple, reducing the The test scale saves test cost.

The invention provides a testing apparatus for fatigue cracking of a pavement on a steel bridge. A test piece is installed on the testing apparatus. The testing apparatus is characterized by comprising a testing platform used for applying load and a testing model used for simulating stress of the test piece, wherein the testing model comprises a support base which is equipped with at least two columns, loading plates are arranged on the columns, and the loading plates are fixed with the test piece through clamps. The invention further provides a testing method for fatigue cracking of the pavement on the steel bridge. The method comprises the following steps: determining the size of the test piece according to the size of the testing platform and load limit; fixing the fabricated test piece and the loading plates together through the clamps; applying load on the testing model by using the testing platform; and predicating the technical state of a pavement layer through displacement observation, foil gauge observation and DIC digital image processing of the state of the test piece in the process of testing, and evaluating the cracking fatigue life of the pavement layer.

The invention provides a fatigue life prediction method and device based on the weighted average maximum shear stress plane, which relates to the field of multiaxial fatigue strength theory. The method includes: (1) passing the multiaxial variable amplitude load history through the von Mises equivalent stress formula The equivalent stress history is synthesized, and the von Mises equivalent stress history is counted by Wang‑Brown multiaxial cycle counting method; (2) The weighted average maximum shear stress plane is used as the high cycle multiaxial variable amplitude load. critical surface; (3) Calculate the fatigue damage parameters on the critical surface of each repetition obtained by counting; (4) use the Zhang-Shang model to calculate the fatigue damage; (5) use Miner’s linear accumulation rule to calculate the The damage is accumulated, and finally the fatigue life is calculated. The weighting function proposed in this method can take into account the main fatigue damage mechanisms under multiaxial loading. The life prediction results show that the life prediction method can better predict the fatigue life under multi-axis constant amplitude and variable amplitude loading.

The invention discloses a steel bridge fatigue evaluation load modeling and fatigue evaluating method. The steel bridge fatigue evaluation load modeling and fatigue evaluating method comprises, step one, establishing a train load model; step two, processing and classifying measured data; step three, according to the measured data, establishing a probability model for parameters; step four, establishing a train load probability model; step five, generating a random load spectrum through a Monte-Carlo method; step six, through finite element analysis, acquiring stress influence lines of steel bridge fatigue details; step seven, performing influence line loading through the random load spectrum to obtain a stress history; step eight, analyzing the stress history to evaluate steel bridge fatigue. The steel bridge fatigue evaluation load modeling and fatigue evaluating method has the advantages of, through the fatigue evaluation load model which is established on the basis of the measured data for describing the load status of currently-running trains, achieving fatigue evaluation of any component of a steel bridge, establishing a complete train load modeling method, improving the utilization value of the measured data and ensuring more accurate and more practical steel bridge fatigue evaluation.

The invention discloses a metal structure fatigue crack expansion life prediction method based on Taylor perturbation series method, and the method comprises the steps of first describing fatigue crack expansion process of the metal structure by employing Paris formula; conducting integration to the Paris formula to obtain an integration-formed crack expansion equation; and conducting Taylor expansion to the crack expansion equation. Then considering apparatus measuring error and structure manufacturing error to make an initial crack length contain a small disturbance; expressing the solution of the crack expansion equation and the initial crack length in perturbation grades by introducing a small parameter Epsilon; determining the perturbation grades according to an nominal value of the initial crack length and the disturbance so as to get the value of each coefficient at an initial time; obtaining a crack expansion perturbation equation in combination with the Taylor expansion of the crack expansion equation based on parameter perturbation theory; then solving the perturbation equation to obtain a fatigue crack expansion length perturbation grades solution; calculating load cycle times when a critical crack length is reached; and taking the load cycle times as a predicted value of the metal structure fatigue crack expansion life.