79 results about "Stress cycle" patented technology

A method for analyzing vortex vibration and fatigue of a depth tension-type vertical pipe, which relates to the field of depth vertical pipe design, comprises the following specific steps of: step 1. obtaining flow field data; step 2. substituting the flow field data into vertical pipe vibration equations 6 and 7; step 3. solving the equations 6 and 7 by using a finite element method, and obtaining calculation results including displacement, velocity, accelerated velocity and stress time interval; and step 4. counting stress cycle number n(i) of an amplitude within a certain time by adopting a rain-flow counting method according to the calculation results, and substituting the n(i) into a fatigue damage calculation formula 8 to calculate the fatigue damage. The method for analyzing vortex vibration and fatigue of the depth tension-type vertical pipe improves the accuracy of stress calculation by adopting a practical pipe-in-pipe model and simultaneously considering direct flow vibration and cross flow vibration.

Provided is a wind turbine blade fatigue life real-time monitoring method. The wind turbine blade fatigue life real-time monitoring method real time measures output power, rotating speed and pitch angle of a wind wheel, and reversely pushes out relative wind speed of a random blade element of the blade according to monitoring data, and then apply blade element-momentum (BEM) principle to calculate loading impacted on each blade element, and then calculate loading of the whole blade through integration, form stress spectrum, and eventually use rain-flow counting method to count stress cycle times and accordingly conduct life loss calculation, and obtain fatigue life of wind turbine blade. The power of the wind turbine acts as a monitoring quantity, wind turbine blade fatigue life is obtained by theoretical calculation. The wind turbine blade fatigue life real-time monitoring method has the advantages that not only accuracy of measured data and reliability of monitoring results are guaranteed, but also the whole monitoring process relies on the existing system, and no large quantity sensor is needed to be additionally install. The wind turbine blade fatigue life real-time monitoring method has the advantages of being convenient in implement, low in monitoring cost and the like. The real-time monitoring method of wind turbine blade fatigue life is an ideal method of analyzing and evaluating wind turbine operating safety.

The invention is a method to determine stress within a formation, the method comprising the steps of: providing a closed reference pressure volume within the formation; providing a flexible diaphragm which can be exposed on one side to formation, and on the other side to the closed reference pressure volume; providing a switch wherein the switch generates a signal based on the diaphragm being in a position indicative of the diaphragm being flexed by pressure on one side of the diaphragm being greater than pressure on the other side of the diaphragm; cycling a pressure within the reference pressure volume to between a pressure at which a signal is generated and a pressure at which a signal is not generated; and determining the formation stress as the pressure at which the signal changes. Another aspect of the invention is the apparatus useful in this method. The switch is preferably an electrical contact that is activated by movement of the diaphragm.

The invention provides a bending fatigue test machine for a steel wire rope in case of alternating load. The bending fatigue test machine comprises a frame, a steel wire rope test piece, a driving wheel, a drive unit, a proximity switch which are arranged on the frame, a power transmission system for driving the driving wheel to circularly rotate, and an electro-hydraulic servo system for supplying the alternating load to the steel wire rope test piece and a tensioning wheel, wherein the driving wheel, the drive unit and the proximity switch are arranged on the frame. In the invention, every time the tensioning wheel circularly rotates back and forth, the electro-hydraulic servo system changes the stress cycle of the steel wire rope once; then the proximity switch sends a counting signal; and finally the fatigue life of the steel wire rope is measured by counting cycle indexes. The test machine can be used for performing bending fatigue tests on various standard steel wire rope test pieces in the case of the alternating load, and applying various alternating loads on the steel wire rope test pieces. The test machine has a simple structure, and is easy to control.

The invention provides an analyzing method for parametric-excitation and vortex-induced vibratory fatigue of a deep-ocean top tension riser. The analyzing method comprises 1) taking regard of vortex induced lift caused by ocean current and parametric excitation caused by platform heave, and establishing a parametric-excitation and vortex-induced vibration model for the riser; 2) calculating heaving movement of a platform under wave effects according to on-site measuring results or a numerical method, and determining the parametric excitation of the riser; 3) analyzing stability of the parametric excitation of the riser, and ensuring that the parametric excitation of the riser is within a stable range; 4) calculating parametric-excitation and vortex-induced vibration response of the riser, and obtaining a time-history stress curve for each point of the riser; 5) calculating a stress cycle index of each point of the riser in a rain-flow counting method; and 6) calculating a fatigue life of the riser via a Miner damage cumulating theory and an S-N curve method. The analyzing method of the invention overcomes the disadvantage that present fatigue analysis based on vortex induced vibration tends to be unsafe, and enables fatigue damage analysis of the riser to satisfy practicality better.

The present invention relates to a method for controlling and for refreshing memory cells in an electrically erasable and programmable memory comprising a memory array organized in sectors, each sector comprising memory cells linked to bit lines and to word lines. The method comprises controlling and refreshing memory cells of pages of the memory array the address of which is indicated by a control and refresh counter comprising data forming tokens usable once. According to the present invention, a control and refresh counter is integrated into each sector of the memory and comprises memory cells linked to the bit lines of the sector. A counter of a sector is erased after reaching a maximum counting value that is chosen so that, when this maximum counting value is reached, memory cells of the counter have undergone a number of electrical stress cycles that is at the most equal to a determined number. Application to Flash memories.

A long life fatigue strength design method for a metallic material is capable of allowing design of an optimum mechanical part according to a set service life by considering an increase in ODA (area affected by hydrogen observed blackish by a metallurgical microscope) size according to the assumed service life of the mechanical part. The method includes obtaining, from the results of a fatigue test, a functional relation between the number of stress cycles to failure and the size of a hydrogen affected area around an inclusion affected by trapped hydrogen. From the functional relation, equivalent defect sizes as the sizes of the inclusions after growth corresponding to the assumed number of cycles of working stress on the mechanical part using the metallic material are obtained, and the mechanical part is designed using the equivalent defect sizes in the calculation of a long life fatigue strength such as allowable stress, whereby a failure life design can be performed with the ODA size growth taken into account according to the assumed service life of the mechanical part.

Provided is a method for testing faults of an antiskid brake control box under complex working conditions. Integrated environment stress and a working current are applied to the antiskid brake control box at the same time, testing of five integrated environment stress cycles is carried out, and therefore the faults, about the integrated environment stress and the working current, of the antiskid brake control box are motivated at the same time. When the antiskid brake control box has the faults in a testing process, technical improvement on fault correction should be conducted, and then testing is conducted again until no fault occurs in the five cycles. According to the method, the capability of the antiskid brake control box to adapt to the integrated environment stress can be enhanced, and therefore the antiskid brake control box has no fault when being used under integrated environment conditions.

The invention discloses an experimental device of 'wet' rotor effect of a multi-stage centrifugal pump, which comprises a multi-stage wet rotor platform (9) and the like, wherein the multi-stage wet rotor platform (9) comprises a pressure-bearing shell which is internally provided with at least two stages of rotor sections, and a rotating shaft (18) passing through the pressure-bearing shell; each stage of rotor section consists of a high pressure bin (25) and a lower pressure bin (24) provided with a pump rotor (26); inter-stage seal (28) is arranged between the high pressure bin (25) and the lower pressure bin (24); the shaft neck part at the root of the pump rotor (26) is provided with a speed displacement sensor (22); a pressure circulating system is respectively communicated with the high pressure bin (25) and the lower pressure bin (24); a driving motor (3) is connected with a rotating shaft (18) by a belt pulley speed changing device (4); and a torque rotating speed measurement instrument (6) is positioned between the belt pulley speed changing device (4) and the rotating shaft (18). The experimental device can be used for measuring the amplitude and the torque of a multi-stage wet rotor along with the change of the rotating speed under the different working pressures and inter-stage seal structures.

The invention discloses a fatigue life calculation method of a welded steel bridge structure. The method comprises steps as follows: a steel fatigue resistance total-space S-N curve model with average stress modification taken into consideration is established; the real stress time history of steel bridge welding details is calculated in consideration of the coupling effect between welding residual stress and vehicle load stress; the real stress time history is processed with a rain flow counting method, and the stress amplitude, average stress and stress cycle number under the condition of single open traffic are calculated on the basis of a processing result; by use of the established total-space S-N curve model with average stress modification taken into consideration, the total stress cycle number corresponding to the stress amplitude and the average stress is calculated; on the basis of the calculated stress cycle number under the condition of single open traffic and the total stress cycle number, the fatigue life of steel bridge welding details is calculated. The influence of the average stress effect on the fatigue life of the welded steel bridge is accurately considered, the defect that existing steel bridge fatigue design standards for fatigue life are too high is overcome, and the method is worth wide application and popularization.

This invention relates to a method to process stress long circle fiber grating module plate, especially to a new method to process fiber grating by use of mechanical stress which is used in fiber communication, filter gain flatness device and sensors. The technique scheme is the following: the stress module is a rectangle organic glass plate with circle strip; to wind the copper wire along the glass plate according to strip image; to put the glass plate after winding to two parallel extra fibers and usual fiber; to exert pressure on the glass plate by use of sprig device.

The invention discloses a method for monitoring the fatigue stress of a ship power pipeline, and relates to the technical field of safety control of the power pipeline. The method comprises the following steps: establishing a stress analysis model of the power pipeline, and generating a stress comparison table of all monitoring points of the pipeline under a unit load condition; obtaining a time history curve of low-period cycle load and high-period cycle load on the pipeline during a ship navigation process; calculating and drawing a cumulative frequency table of low-period stress cycles of the monitoring points; calculating an equivalent gravity load factor of the pipeline; calculating the cumulative frequency table of high-period stress cycles of the monitoring points; and merging the cumulative frequency table of the low-period stress cycles with the cumulative frequency table of the high-period stress cycles of the monitoring points to obtain a complete cumulative frequency tableof stress cycle, so as to complete the fatigue analysis and check of the monitoring points of the ship pipeline. By adopting the method disclosed by the invention, the setting of sensors can be reduced, the situation that the sensors are directly attached to dangerous points for measurement is avoided, and the stress monitoring of any area in the ship power pipeline is completed indirectly.

The invention discloses a metal structure fatigue life calculation method based on a material corrosion damage factor and a weld crack damage factor.Damage factors of two factors of corrosion and weldjoint of the steel structure to the yield strength of the steel structure are obtained; finally, the yield limit of the material after aging along with time is solved; a model of the steel structureyield characteristics changing along with time is established by utilizing the factors, so that the reliable yield strength limit of the steel structure is obtained, an intersection point exists at acertain position by utilizing a steel structure S-N curve considering damage factors and a stress cycle, and the intersection point is a residual service life value needing to be predicted by people.According to the method, the influence of corrosion and weld crack damage on the metal structure of the hoisting machine in actual use is fully considered, and a material corrosion factor and a weld crack damage factor are introduced, so that a calculation result is more practical and accurate, and the method is suitable for application of metal structure safety assessment.

A method for calculating a fatigue usage factor of a component in a nuclear reactor includes determining a flow scaling factor for each stress component of a stress cycle, applying the flow scaling factor to rapid cycling stress conditions, and performing a fatique evaluation by calculating a fatigue usage factor using the flow scaling factor. The flow scaling factor is a ratio of a temperature fluctuation ratio at a first reactor operating condition divided by a temperature fluctuation ratio at a second reactor operating condition. The temperature fluctuation ratio is defined as a ratio of the metal temperature range over the fluid temperature range.

The invention discloses a rail train bogie fatigue life estimation method. The method comprises the steps: S1, establishing a finite element analysis model of a bogie framework; s2, applying a boundary condition and an external required load to the finite element analysis model constructed in the step S1, and performing finite element analysis and calculation; s3, selecting a stress monitoring point for stress monitoring, and inversing the numerical relationship BX = Y between the monitoring point and the external load, wherein B is a coefficient matrix, X is an external load column matrix, and Y is a value matrix of the stress monitoring point; s4, arranging stress monitoring points on the actual bogie, monitoring stress, obtaining an actual stress monitoring value, and meanwhile calculating the actual external load in combination with the numerical relationship between the monitoring points obtained in the step S3 and the external load; and S5, applying the actual external load calculated in the step S4 to the finite element model in the step S1 for analysis, and selecting a node with a relatively large stress cycle for fatigue life estimation, thereby predicting the residual life of the framework and guiding the actual operation of the train.

The invention relates to a dynamic stress accelerated life test profile compilation method. The method comprises the following steps that 1, on the basis of a damage equivalent principle, dynamic stress is converted into static stress within a certain time interval; 2, on the basis of the step 1, an equivalent relation of a dynamic stress accelerated factor and a static stress accelerated factor is obtained; 3, the dynamic temperature stress is adopted as the dynamic stress, and on the basis of an Arrhenius model, dynamic temperature accelerated stress accelerated factor computational formulais obtained; 4, the dynamic temperature accelerated stress profile is compiled, and three parameters including a dynamic temperature accelerated stress mean value Tm*, a dynamic temperature accelerated stress amplitude Ta* and a dynamic temperature accelerated stress cycle period w* are determined. According to the method, the dynamic stress accelerated life test profile can be designed accordingto the dynamic change environment actually adopted by products, the reality degree simulated by the environment conditions in the accelerated test is improved, and it is ensured that the product failure mechanism in the test is consistent to that under the actual service condition.

The invention discloses a testing device and method for the shear modulus of a geotextile interlayer of an asphalt concrete structure. When the shear modulus is tested, a test piece of asphalt concrete structure to be tested is located between two side clamp plates, a loading spring fixed to the two side clamp plates applies required lateral pressure to the test piece to be tested. A cyclic shearload is applied by a loading plate, and relative displacement caused by cyclic shear force is monitored by four displacement sensors. The whole testing device is connected with a base through two fixing beams and fixing bolts. According to the size of the test piece, the applied load and the relative displacement recorded by the displacement sensors, the shear modulus of the geotextile interlayerunder specific testing temperature, loading frequency and lateral pressure conditions can be calculated. The testing device is simple in structure and low in cost, and the testing method is easy to master. The problems of testing the shear modulus of the geotextile interlayer in the asphalt concrete structure under different temperature, lateral pressure and loading frequency conditions are solved.

The invention provides an asphalt mixture multi-sequence local loading high temperature performance test method. the method includes the following steps: firstly, determining the number of stress levels and the magnitude of stress applied to a test piece in a test according to actual axle load spectrum distribution of an expressway, forming a large rotating compacted test piece and cutting the upper and lower end faces of the test piece, and determining a holding temperature of a material according to layers applied the material in practical engineering; secondly, determining the diameter of ametal indenter used in the teat according to the size of the test piece, and arranging preloaded stress levels and loading times and stress cycles and loading times in multi-sequence loading; and finally, calculating permanent strain rates under the sequences according to a creep curve after the test is finished. The relationship between the permanent strain rate of the material and the stress levels under more realistic conditions can be efficiently and accurately obtained by using the method, and the high temperature of different asphalt mixtures can be compared under the multiple stress levels.

The invention provides a speed reducer fatigue acceleration test and residual life prediction method and a storage processing system, and relates to the technical field of machine learning. The method comprises the following steps: fatigue performance parameters of a to-be-predicted speed reducer are obtained, the fatigue performance parameters comprise the average fault-free time and the stress cycle number, and the fatigue performance parameters are fatigue life characterization parameters in an ideal state; a performance degradation model of the speed reducer is constructed based on the fatigue performance parameters; a pre-constructed fatigue acceleration model and a pre-constructed performance degradation model are adopted, acceleration factors are screened, an acceleration test is carried out, the fatigue durability of the speed reducer in the current stage and a performance degradation test result are obtained, and the fatigue durability of the current stage comprises the remaining average fault-free time and the remaining stress cycle number; and the residual life of the speed reducer is predicted according to the fatigue durability of the current stage. The method can improve the efficiency and accuracy of residual life prediction of the speed reducer.

The invention relates to a multilayer rolling bearing, which comprises an inner ring, at least one middle ring, an outer ring and at least two rolling layers, wherein the rolling layers comprises an inner rolling layer and an outer rolling layer, each rolling layer comprises a rolling body and a retainer, each retainer is used for containing rolling bodies so that the positions between the rolling bodies are relatively fixed, two rolling bodies positioned in the inner rolling layer form a row in a side-by-side way, a plurality of rows of rolling bodies are distributed in each retainer, and the axial lines of the side-by-side rolling bodies are parallel to the axial line of the inner rolling layer. The multilayer rolling bearing has the advantages that the number of stress cycle times and the number of rolling times of the rolling bodies in the rolling process are reduced, so the service life is prolonged, and the bearing safety is improved.

The invention discloses a power transmission tower structure full-life multi-disaster resistance evaluation method considering a wind-induced fatigue effect, and the method comprises the steps: building a power transmission tower structure model, and selecting and simulating a seismic wave and coherent wind load time history suitable for the structure; actually measured wind speed and wind direction data of the structure are collected, and the occurrence probability and annual duration of different wind speeds and wind directions are calculated; simulating and generating wind load time histories of different wind speeds and wind directions according to the actually measured data, and loading the power transmission tower structure to obtain a structure stress response time history; the stress cycle of the structural rod piece under the wind load effect is counted, and fatigue accumulated damage of the structural rod piece in unit time is calculated; according to the fatigue accumulated damage of the structural rod piece and the material fatigue performance time-varying model, material parameters of the structural rod piece in different life cycles are updated, and time-varying finite element models of different life stages considering wind-induced fatigue performance degradation are established; and performing multi-disaster resistance evaluation on the model in the whole life cycle, and verifying the influence of the wind-induced fatigue effect on the multi-disaster resistance of the structure in different life stages.

The pressure and circulation culture apparatus includes a holder (culture chamber part), a pressure transmission part and a culture solution circulation line (culture circuit). The holder is a means that reserves culture solution and that holds a cultured object. The pressure transmission part is a means that communicates with the holder and transmits an external pressure to the culture solution. The culture solution circulation line is a means that is connected to the holder via the pressure transmission part, and circulates the culture solution through the holder via the pressure transmission part. Such a structure is included, and an external pressure is made to operate on the culture solution via the pressure transmission part to allow pressure on the cultured object in the holder and circulation of the culture solution in the holder.

The invention belongs to the technical field of bridge dead load stress testing, and discloses a concrete bridge dead load stress testing system and method and an information data processing terminal.The concrete bridge dead load stress test system comprises a bridge image acquisition module, a bearing acquisition module, a bridge prestress detection module, a main control module, a bridge modelconstruction module, a parameter import module, a simulation test module, an analysis module, a storage module and a display module. The real-time relationship between the tension strength (tension force) and the tension displacement is established through real-time measurement data by the bridge prestress detection module, the magnitude and uniformity of effective prestress are intelligently controlled, and the bridge prestress detection precision is improved; and moreover, the analysis module is used for obtaining the stress cycle data of a to-be-analyzed bridge through adoption of a data simulation method based on the actually measured traffic flow data of the to-be-analyzed bridge, the theory is scientific, the analysis result is scientific and reliable, the applicability is high, andimportant engineering significance is achieved.

The invention relates to a representation method of a metal material fatigue curve. The method comprises the steps that 1, a metal material fatigue life range, different stress ratios R under the stress concentration condition and a metal material fatigue life S-N curve are determined; 2, three groups of values of limit stress S and cycle number N are selected according to the S-N curve obtained in the step 1; 3, the three groups of numerical values selected in the step 2 are substituted into a following formula (please see the formula in the description), and numerical values of q, m and c are solved; 4, a function, that is, an expression of the metal material fatigue performance curve in the step 3 is determined according to the numerical values, solved in the step 3, of q, m and c. According to the representation method of the metal material fatigue curve, life point data corresponding to various stress cycle conditions can be quickly and precisely determined, the structure fatigue analysis period can be shortened, and the work tediousness degree can be reduced.

The invention discloses a gas cylinder fatigue testing machine which comprises an electrical control cabinet system, a pressurization system and a test well; the electrical control cabinet system is composed of a cabinet body, a control table, a host machine, a display and a printer; the pressurization system is composed of a box body and a pressure pump group; and the pressure pump group in the pressurization system is electrically connected with the host machine in the electrical control cabinet system and is connected with a tested gas cylinder in the test well through a high-pressure pipeline. The gas cylinder fatigue testing machine provided by the invention is formed by the control table, the host machine, the pressure pump group, a pressure and temperature sensor and the high-pressure pipeline; by adopting a microcomputer control technology, all the test process can be operated on the control table, and values of a test time, a pressure circulation waveform, a deformation curve,a test pressure and the like are displayed in real time, a test result can be automatically stored and can be printed and output; by adopting a microcomputer to perform data processing and analysis,records are automatically controlled, a test report is automatically formed and the like, so that the gas cylinder fatigue testing machine is simple to operate and is safe and reliable.

The invention relates to a method for compiling a test load spectrum, which comprises the steps of selecting a stress reference point, processing a measured data signal, setting a threshold value of an invalid stress cycle, judging an invalid stress cycle, determining an invalid load period and connecting a breakpoint. This method can shorten the test cycle, reflect the loading condition of key components, and satisfy the principle of damage consistency before and after concentration.

The invention discloses a fiber-reinforced composite material foundation bolt. The fiber-reinforced composite material foundation bolt comprises an inner core structure and an outer-layer structure, wherein the inner core material is an aramid fiber-reinforced composite material; the outer-layer material is a basalt fiber-reinforced composite material; and a diameter ratio of the inner core to the outer layer is 3 to 4. The fiber-reinforced composite material foundation bolt disclosed by the invention has relatively strong corrosion resistance and fatigue resistance under low-stress cycles such as wind load, and is long in service life.