12 results about "Bending fatigue test" patented technology

The application discloses a kind of asphalt mixture fatigue life prediction methods, comprising the following steps: S1, making the standard test piece of asphalt mixture;S2, the three-point bending fatigue test of asphalt mixture under different stress levels is carried out to the standard test piece made under the setting parameter;S3, according to the stress-strain hysteresis curve of asphalt mixture is fitted to test data;S4, the accuracy of the stress-strain hysteresis curve obtained is verified;S5, based on the hysteresis curve, the fatigue damage variable of asphalt mixture is constructed;S6, the fatigue life prediction model of asphalt mixture is constructed.The method of the application avoids the defect that the relative change rate of dissipation energy is the discrete index data of prediction fatigue life, so as to improve the prediction accuracy of asphalt mixture fatigue life, the model construction step is less, form is simple, and has higher practical value.

This invention provides a high-temperature three-point bending ultrasonic fatigue testing device and its usage method, which can be used to conduct high-temperature and ultra-high-temperature three-point bending fatigue tests on materials. This invention overcomes the limitation of traditional three-point bending ultrasonic fatigue tests, which can only be performed at room temperature, bringing a novel fatigue testing method. Furthermore, the combined fixture device adopts a modular design, making it simple to process and operate, and easy to replace.

The application discloses a kind of asphalt pavement asphalt mixture layer fatigue life prediction method, belong to data processing technical field, including preparation asphalt pavement structure fatigue life calculation layer asphalt mixture sample;Using beam four-point bending testing machine to carry out bending fatigue test to asphalt mixture, test the fatigue life of asphalt mixture under different test temperatures and strain levels, in combination with fatigue life test results, take the average of each test temperature and strain level combination, deduce fatigue life prediction model based on different each type asphalt mixture;According to the parameters of fatigue life prediction model based on different types of asphalt mixture, determine asphalt mixture layer fatigue cracking life model.The application constructs the fatigue life prediction model of pavement structure asphalt layer based on different types of asphalt mixture, and can realize the fatigue life prediction of asphalt pavement asphalt mixture layer for more than 30 years, is favorable for the accurate design and maintenance of long-life asphalt pavement structure.

This invention relates to the field of material fatigue testing technology, and more particularly to a high-temperature rotary bending fatigue testing device capable of simulating different salt spray environments. Addressing the problem of existing equipment providing only a single environmental simulation, the high-temperature rotary bending fatigue testing device proposed in this invention includes an environmental cabinet with a shock-absorbing wooden block at the top; it also includes an environmental simulation mechanism, a salt spray supply and control mechanism, and a rotary bending loading mechanism. The environmental simulation mechanism is located on top of the shock-absorbing wooden block; the salt spray supply and control mechanism is located inside the environmental cabinet and communicates with the interior of the environmental simulation mechanism, used to control the concentration and flow rate of the salt spray supplied to the environmental simulation mechanism; the rotary bending loading mechanism is located on top of the shock-absorbing wooden block and coaxially connected to the environmental simulation mechanism, used for rotary bending of the test specimen. The high-temperature rotary bending fatigue testing device of this invention can closely simulate real service environments.

The application discloses a medical catheter bending fatigue test method and system based on a geometric model quantitative conversion, and comprises the following steps: obtaining an initial clamping distance of a to-be-tested catheter, and setting a target bending angle; based on a geometric model that approximates a bent catheter axis to a circular arc, a displacement amount of a movable crossbeam is calculated, and a quantitative mapping is formed between the displacement amount and the target bending angle through a geometric relationship of an arc length, a chord length and a bending angle of the circular arc; the movable crossbeam is controlled to perform periodic reciprocating motion with the displacement amount as an amplitude, so that the to-be-tested catheter is cyclically switched between a straight state and a bending state; in the bending-relaxing cycle process, force values of each cycle are collected in real time, peak forces of each cycle are extracted, and a peak force attenuation curve is generated with the cycle number as an abscissa and the peak force as an ordinate; and failure is determined according to the peak force attenuation curve. The application realizes standardized and quantitative test of bending fatigue, and improves the pertinence and scientificity of the test.

The method for predicting the service life of the coiled tubing under the cooperation of plasticity and damage is characterized in that the fatigue service life and the strain amplitude under the specific curvature radius are obtained through a full-size bending fatigue test, and the fatigue service life and the strain amplitude are substituted into a Manson-Coffin model to invert an unknown coefficient; the method comprises the following steps: determining mechanical parameters of a material in combination with a uniaxial tensile test, constructing a finite element mechanical model, carrying out finite element simulation on bending working conditions of a damaged coiled tubing on a roller and a guider, extracting strain amplitudes, and further establishing strain amplitude calculation models under different working conditions by adopting a Levenberg-Marquardt algorithm; coupling the model with a Manson-Coffin equation, and respectively constructing fatigue life prediction models of the roller and the guider; and on the basis of the Miner theory, three times of bending cycles with different curvatures in one trip are regarded as complete load cycles, an accumulated damage value is calculated, a correction coefficient is determined through low-cycle fatigue finite element simulation, a calculation model of the number of remaining trip times is established, and quantitative prediction of the remaining life is achieved. The method is suitable for the technical field of petroleum and natural gas drilling engineering.

The application discloses a kind of laser cladding repair axle class part fatigue life prediction method and system, comprising: obtaining each test piece microdefect feature, the heterogeneous structure feature of the microstructure of cladding layer-heat affected zone-substrate, carry out rotating bending fatigue test, obtain the rotating bending fatigue life data corresponding to microdefect feature, heterogeneous structure feature, and establish the fatigue life label corresponding to data;Establish the initial data set including cladding layer microdefect feature parameter, heterogeneous structure feature parameter and axle fatigue life data;And the data set is pretreated and reduced dimension processing;Establish feature extraction model, adopt random forest regression model to carry out feature importance quantification, identify key feature;The fatigue life prediction model of XGBoost algorithm is constructed, the feature parameter of the high independence of microdefect and heterogeneous structure is obtained, and the key feature parameter and weight are screened out, to carry out residual fatigue life prediction based on fracture mechanics framework.

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.

This invention discloses a deflection measuring device for axial bending fatigue testing, relating to the field of road engineering technology. It includes a base, with the lower end of a connecting rod fixedly connected to the base, and the upper end of the connecting rod fixedly connected to a disc clamp. The disc clamp is threadedly connected to a deflection measuring component. It also includes an upper loading head and a lower loading head, with the working ends of the upper and lower loading heads positioned opposite each other. The non-working ends of both the upper and lower loading heads are fixedly connected to a loading device, and the interior of the lower loading head mates with the deflection measuring component. This invention overcomes the measurement error problem in current axial bending fatigue tests, simplifies the testing process, and allows for more accurate and efficient evaluation of the fatigue characteristics of the specimen.

This utility model discloses a glass cover plate bending fatigue testing device, including a housing, a motor, and two adsorption components arranged left and right. One adsorption component is fixedly connected to the housing, and the other adsorption component is rotatably connected to the housing and driven by the motor to realize the opening and closing of the two adsorption components. The adsorption component includes an adsorption plate and a pressing mechanism. The upper side of the adsorption plate is provided with a vacuum suction hole. The pressing mechanism is located at the inner edge of the adsorption plate and includes a tensioner and a pressure band. Limiting grooves are provided on the front and rear sides of the adsorption plate. The width of the limiting grooves is adapted to the width of the pressure band. The pressure band passes over the upper edge of the adsorption plate in the front-rear direction. Both ends of the pressure band pass through the corresponding limiting grooves and extend to the lower side of the adsorption plate. The tensioner is installed on the lower side of the adsorption plate and connected to the end of the pressure band to tighten or loosen the pressure band. This utility model proposes a testing device to improve the fixing effect of glass cover plates.