CN112487580B - Nuclear power plant important pump gear box operational state evaluation method - Google Patents
Nuclear power plant important pump gear box operational state evaluation method Download PDFInfo
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- 238000011156 evaluation Methods 0.000 title abstract description 8
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- 229910018487 Ni—Cr Inorganic materials 0.000 description 1
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Abstract
The invention discloses a method for evaluating the operational state of an important pump gearbox of a nuclear power plant, which comprises the following steps: s1, regularly detecting the surface morphology of a gear of an important pump gear box, and judging whether the gear fails according to failure standards; s2, building a material cyclic stress-strain curve, S3, and determining a stress course; s4, drawing an S-N curve; s5, modeling analysis: establishing a gear box operation model, and acquiring stress states of different positions on the gear surface in the dynamic meshing process of the gear by adopting stress simulation analysis; s6, fatigue life calculation: and calculating the service life of each part of gears in the gear set when the gears are subjected to fatigue fracture, and simultaneously obtaining stress states of different positions on the surfaces of the gears. The invention provides an effective method for evaluating the operable life of a gear box, which is used as an effective evaluation means for judging the operability of the gear box so as to improve the operation reliability of equipment and guide on-site operation and maintenance strategies.
Description
Technical Field
The invention belongs to the technical field of nuclear power, relates to a method for evaluating the operable life of a gearbox, and particularly relates to a method for evaluating the operable state of an important pump gearbox of a nuclear power plant.
Background
The gear box equipped with the important pump set of the nuclear power plant has the technical characteristics of high transmission power, high reliability requirement and the like, and the gear tooth surface flaking and even the fatigue caused tooth breakage occur repeatedly during long-term operation. For an important pump set of a nuclear power plant, such as a circulating water pump, if a gear box fails, the power of the unit is reduced, even the unit is stopped, and great economic loss is caused. Therefore, it is necessary to study the failure mechanism of the important pump gear box of the nuclear power plant, predict the service life of the gear box in advance, and study a complete set of operational performance of the gear box to carry out evaluation technical methods so as to guide the on-site operation and maintenance work of the important pump gear box.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides an effective method for evaluating the operational life of the gear box, which is used as an effective evaluation means for judging the operational performance of the gear box so as to improve the operational reliability of equipment and guide the on-site operation and maintenance strategy.
The technical scheme adopted for solving the technical problems is as follows:
an evaluation method for the operational state of a gearbox of an important pump of a nuclear power plant comprises the following steps:
s1, detecting the surface morphology of gears of an important pump gear box regularly, judging whether the gears fail according to failure standards, and if the failure standards are met, replacing new gears; if the failure standard is not met, the next step is carried out;
s2, building a material cyclic stress strain curve: according to the actual material and surface treatment state of the on-site used gear, establishing a cyclic stress-strain curve of the top point of the hysteresis ring which is connected by taking strain epsilon as an abscissa and stress sigma as an ordinate;
s3, determining stress history: determining the load-time history of a pump motor by actually measuring interface equipment or according to design parameters, and converting the load-time history into a local stress-time history of the gear dangerous point position according to a cyclic stress-strain curve aiming at the gear dangerous point position;
s4, drawing an S-N curve: manufacturing a test piece consistent with a gear of the gear box, performing a fatigue test, measuring the number N of cycles when the test piece breaks, and drawing an S-N curve;
s5, modeling analysis: establishing a gear box operation model, and acquiring stress states of different positions on the gear surface in the dynamic meshing process of the gear by adopting stress simulation analysis;
s6, fatigue life calculation: respectively calculating the service life of each part gear in the gear set when in fatigue fracture through the following formula;
wherein, the stress level progression of the l-amplitude load;
n i -number of cycles at each stress level;
N i -a limit number of cycles at which fatigue failure of the material occurs at each stress level;
d-total fatigue damage;
n-fatigue life;
t s -simulation time in seconds;
t-fatigue life time, unit year.
In the method for evaluating the operational state of the important pump gearbox of the nuclear power plant, preferably in the step S5, stress states of different positions on the gear surface in the dynamic meshing process of the gear are obtained by adding simulation analysis under different gear surface roughness.
In the method for evaluating the operational state of the important pump gearbox of a nuclear power plant, preferably, in the step S2, the surface treatment state of the gear is obtained through metallographic structure sampling analysis.
In the method for evaluating the operational status of the important pump gearbox of a nuclear power plant, preferably in the step S3, the load-time history of the pump motor is determined by actually measuring the interface device or according to the design parameters as follows: when the pump set actually operates, the interface equipment is actually measured to transmit torque and data of transient change at the initial stage of starting the pump, and the torque transmitted to the gear pair is calculated; and meanwhile, obtaining the load-time history of the pump motor according to the gear design experience data, the start-stop impact use coefficient and the load non-uniformity coefficient of the gear pair.
Further, in the method for evaluating the operational status of the important pump gearbox of a nuclear power plant, preferably in the step S4, the drawing of the S-N curve means: carrying out fatigue test on the test piece, applying different stress amplitudes under certain average stress sigma m or certain cyclic characteristic R, and measuring the cyclic number N of the test piece when the test piece breaks; and drawing points and connecting corresponding S-N curves by taking sigma max as an ordinate and N as an abscissa.
Further, in the method for evaluating the operational status of the important pump gearbox of a nuclear power plant, preferably in the step S5, the establishing a gearbox operational model is as follows: and establishing a three-dimensional model of the operation of the gear box by adopting a finite element method according to the design or actual measurement parameters of the gear box.
In the method for evaluating the operational state of the important pump gearbox of a nuclear power plant, preferably, in the step S5, the stress simulation analysis is performed by dividing the gearbox into at least two partial engagement structures according to the gear engagement effect.
In the method for evaluating the operational state of the important pump gearbox of the nuclear power plant, preferably, in the step S5, stress simulation analysis is performed to calculate the service lives of gears of each component in the gear set when fatigue fracture occurs according to the material properties and the surface friction state conditions of the different gear components, and simultaneously obtain stress states of different positions on the surfaces of the gears.
The invention is based on the actual working condition of the important pump set of the nuclear power plant, calculates the maximum stress area in the working process of the gear box by means of combining detection and simulation calculation with the on-site actual working condition, and simulates and calculates the theoretical operation residual life of the gear tooth structure of the gear box. The evaluation method is reliable and is used as a basis for in-service inspection of the on-site operation of the gearbox and establishment of related operation and maintenance strategies.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a block diagram of an embodiment of the present invention;
FIG. 2 is a cyclic stress-strain graph of an embodiment of the present invention;
FIG. 3 is an S-N plot of a material of an embodiment of the present invention;
FIG. 4 is a discretized model of the sun-planet local structure of an embodiment of the invention;
FIG. 5 is a schematic diagram of a discrete grid refinement of a sun gear of an embodiment of the present invention;
FIG. 6 is a detailed partial enlarged view of a discrete grid of sun gears of an embodiment of the present invention;
fig. 7 shows a discretized model of the planet-ring gear partial structure of an embodiment of the invention;
fig. 8 is a schematic diagram of a discrete grid refinement of an annulus gear according to an embodiment of the present invention;
fig. 9 is a detailed partial enlarged view of the discrete mesh of the ring gear of the embodiment of the present invention;
FIG. 10 is a graph of individual gear life curves for different roughnesses for an embodiment of the present invention.
Detailed Description
For a clearer understanding of technical features, objects and effects of the present invention, a detailed description of embodiments of the present invention will be made with reference to the accompanying drawings.
As shown in FIG. 1, the method for evaluating the operational state of the important pump gearbox of the nuclear power plant comprises the following steps:
s1, detecting the surface morphology of gears of an important pump gear box regularly, judging whether the gears fail according to failure standards, and if the failure standards are met, replacing new gears; if the failure standard is not met, the next step is performed.
The surface topography detection adopts a three-dimensional non-contact surface topography instrument. The three-dimensional non-contact surface topography instrument is a common instrument in the mechanical field and will not be described in detail.
The detection items comprise the three-dimensional appearance of the surface, the depth and the size of tooth surface micropunching and pitting and the distribution thereof.
The failure judgment standard is JB/T5664-2007 or directly scrapped or continued to operate according to the operation experience suggestion.
S2, building a material cyclic stress strain curve: according to the actual material and surface treatment state of the on-site used gear, establishing a cyclic stress-strain curve of the top point of the hysteresis ring which is connected by taking strain epsilon as an abscissa and stress sigma as an ordinate; the cyclic stress-strain curve is a conventional technique in the mechanical arts and will not be described in detail herein.
Since the load-time history determination needs to be performed through the measured parameters or design parameters of the interface device, the method mainly comprises the following steps: materials and surface treatment conditions. The gear material may be different according to practical application, for example: steel, aluminum alloy material.
And obtaining the surface treatment state of the gear through metallographic structure sampling analysis. The surface treatment state is a heat treatment state, and the heat treatment includes carburizing heat treatment, nitriding heat treatment, and general heat treatment.
S3, determining stress history: determining the load-time history of a pump motor by actually measuring interface equipment or according to design parameters, and converting the load-time history into a local stress-time history of the gear dangerous point position according to a cyclic stress-strain curve aiming at the gear dangerous point position;
specifically, the load-time history of the pump motor is determined by actually measuring the interface device or according to design parameters: when the pump set actually operates, actually measuring data of transmission torque and transient change at the initial stage of starting the pump, and calculating to obtain the torque transmitted to the gear pair; and meanwhile, obtaining the load-time history of the pump motor according to the gear design experience data, the start-stop impact use coefficient and the load non-uniformity coefficient of the gear pair.
The calculation and conversion of this step is a matter of ordinary skill in the art and will not be described in detail herein.
S4, drawing an S-N curve: and (3) manufacturing a test piece consistent with the gear of the gear box, performing a fatigue test, measuring the number N of cycles when the test piece breaks, and drawing an S-N curve.
The S-N curve refers to a curve that relates the level of applied stress to the fatigue life of a standard sample, and is generally a curve that represents the relationship between median fatigue life and applied stress, and is therefore also referred to as the median S-N curve. Specifically, plotting an S-N curve refers to: performing fatigue test on the test piece under a certain average stress sigma m Or applying different stress amplitudes under a certain cyclic characteristic R, and measuring the cyclic number N of the test piece when the test piece breaks; sigma of max And (3) drawing points and connecting to obtain corresponding S-N curves by taking the ordinate and the N as the abscissa.
The FE-SAFE software provides a comprehensive material fatigue property material library and material library management system, contains hundreds of common fatigue materials of steel and aluminum alloy materials, and can directly form an S-N curve through the software. The S-N curve provided by FE-SAFE is a curve on a double logarithmic scale.
If the existing data and the existing gear fatigue test S-N curve cannot be passed, the tensile strength (UTS) and the elastic modulus E of the material can be utilized to approximate the material fatigue data.
S5, modeling analysis: and (3) establishing a gearbox operation model, and acquiring stress states of different positions on the gear surface in the dynamic meshing process of the gear by adopting stress simulation analysis.
The establishment of the gear box operation model is as follows: and establishing a three-dimensional model of the operation of the gear box by adopting a finite element method according to the design or actual measurement parameters of the gear box.
The stress simulation analysis is to divide the gear box into at least two partial meshing structures according to the meshing action of gears for simulation analysis.
S6, fatigue life calculation: the life at fatigue fracture of each component gear in the gear set was calculated separately by:
wherein, the stress level progression of the l-amplitude load;
ni—number of cycles at each stress level;
ni-the limit number of cycles at which fatigue failure occurs for the material at each stress level;
d-total fatigue damage;
n-fatigue life;
ts-simulation time, unit seconds;
t-fatigue life time, unit year.
The following describes the CRF circulating water pump gear box of the nuclear power plant in detail.
The nuclear power plant CRF circulating water pump gear box comprises a set of planetary gear speed reducer, and consists of a sun gear, an annular gear, a planet carrier and four planet gears. Wherein the sun gear is driven by a motor shaft and the pump shaft is driven by a planet carrier.
An evaluation method for the operational state of a gearbox of an important pump of a nuclear power plant comprises the following steps:
s1, detecting the surface morphology of gears of an important pump gear box regularly, judging whether the gears fail according to failure standards, and if the failure standards are met, replacing new gears; if the failure standard is not met, the next step is performed.
In the step, a three-dimensional non-contact surface morphology instrument is adopted for surface morphology detection, and the three-dimensional non-contact surface morphology instrument adopts an international forefront white light axial chromatic aberration technology (also called a white light quasi-confocal technology) to realize rapid, high-resolution and large-range three-dimensional surface morphology measurement and related parameter measurement. The method is mainly used for detecting the roughness of the tooth surface, wherein detection items comprise the three-dimensional appearance of the surface, the micro-pitting corrosion of the tooth surface, the depth and the size of pitting corrosion and the distribution of the depth and the size, wherein the accurate pit number can be achieved, and the micro-pitting corrosion diameter is accurate to 0.001mm. The failure judgment standard of pitting and spalling is shown in JB/T5664-2007 or suggested to be directly scrapped or continuously operated according to operation experience.
In this embodiment, sun gear, ring gear, planet carrier, four planet gears are detected, and the detection result is:
TABLE 1 three-dimensional surface topography measurement test results
| Part name | Exfoliation of | Number of pits | Cracking of | Broken tooth | Micro pitting diameter |
| Sun gear | Without any means for | 1 | Without any means for | Without any means for | 1mm |
| Inner gear ring | Without any means for | 1 | Without any means for | Without any means for | 2mm |
| Planet carrier | Without any means for | Without any means for | Without any means for | Without any means for | Without any means for |
| First star wheel | Without any means for | Without any means for | Without any means for | Without any means for | Without any means for |
| Second star wheel | Without any means for | Without any means for | Without any means for | Without any means for | Without any means for |
| Third star wheel | Without any means for | Without any means for | Without any means for | Without any means for | Without any means for |
| Fourth star wheel | Without any means for | Without any means for | Without any means for | Without any means for | Without any means for |
By JB/T5664-2007 standard comparison, the planetary gear speed reduction device does not reach the failure standard and can continue to operate. In order to further predict the remaining operating life of the planetary gear reducer, the following steps are performed.
If the gear is a new gear, the step S1 is not needed, and the step S2 is directly carried out.
S2, building a material cyclic stress strain curve: according to the actual materials and surface treatment state of the on-site used gears, a cyclic stress-strain curve of the top point of the hysteresis loop is established, wherein the cyclic stress-strain curve is connected by taking the strain epsilon as an abscissa and the stress sigma as an ordinate.
The main structure of the CRF circulating water pump gear box is as follows: the planet wheel, the sun wheel and the inner gear ring are made of BS 970G 655M13, and are subjected to surface heat treatment in a carburizing and quenching mode; the inner gear ring is made of BS970 722M24T, and is subjected to surface heat treatment in a nitriding mode.
From the above material characteristics, a cyclic stress-strain curve as shown in fig. 2 was established.
S3, determining stress history: actually measuring data of transmission torque and transient change at the initial stage of starting the pump when the pump set actually operates through actually measured parameters or design parameters of the interface equipment, and calculating to obtain the torque transmitted to the gear pair; meanwhile, according to the gear design experience data, the start-stop impact use coefficient and the gear pair load non-uniformity coefficient, the pump motor load-time history is obtained, and according to the gear dangerous point position, the load-time history is converted into the local stress-time history of the gear dangerous point position according to the cyclic stress-strain curve.
In this embodiment, the parameters of the gearbox are:
TABLE 2 essential parameters of gearbox
| Parameter name | Numerical value | Parameter name | Numerical value |
| Transmission power | 4500kW | Tooth number of toothed ring | 94 |
| Input rotational speed | 744rpm | Modulus of | 8.467 |
| Reduction ratio | 4.615:1 | Pressure angle | 22.5° |
| Weight of gear box | 12000kg | Helix angle | 30° |
| Lubricating oil model | ISO VG 100 | Modulus of elasticity | 206GPa |
| Number of sun gear teeth | 26 | Poisson's ratio | 0.3 |
| Tooth number of planet wheel | 4*34 | Density of | 7850kg/m 3 |
In this embodiment, the torque Ta applied to the sun gear is calculated as follows:
Ta＝9550*P/n/4*KA*Kp
wherein: p is motor power 4500Kw
n is the rotation speed 744rpm of the sun wheel
KA is a use coefficient, and takes factors such as start-stop impact and the like into consideration, the numerical value is selected to be 1.6-1.7 empirically
Kp is a planet load non-uniformity coefficient, and is empirically selected to be 1.05 considering that the components in the planet packet are all floating
The torque Tc is applied to the planet wheel, and the Tc is calculated as follows:
Tc＝9550*P/n/4*i*KA*Kp
wherein: p is motor power 4500Kw
n is the rotation speed 744rpm of the sun wheel
i is the ratio of the planet to sun, i=zc/za=34/26= 1.308
KA is a use coefficient, and takes factors such as start-stop impact and the like into consideration, the numerical value is selected to be 1.6-1.7 empirically
Kp is a planet load non-uniformity coefficient and is empirically selected to be 1.05 considering that the components within the planetary pack are all floating.
Selecting a tooth surface friction coefficient: taking the friction coefficient between the inner gear ring and the planet wheel as 0.05.
S4, drawing an S-N curve: and (3) performing a fatigue test on the test piece, and drawing an S-N curve after measuring the number N of cycles when the test piece breaks.
The S-N curve may be formed directly by the FE-SAFE software or may be obtained as follows.
In this embodiment, the S-N curves of BS 970G 722M24T and BS 970G 655M13 cannot be obtained by the existing data and the existing gear fatigue test S-N curves, so the Seeger material approximation algorithm is adopted for calculation:
material fatigue data is approximated using the tensile strength (UTS) and elastic modulus E of the material.
According to the 15 th gear material of the gear handbook and the approximate comparison table of the heat treatment table 15.2-20 China and common steel numbers of other countries, BS 970G 655M13 national standard approximate mark is 12CrNi3, and UTS of 12CrNi3 in GB/T3077-1999 is 930MPa.
BS970 722M24T has no similar material in the approximate comparison table of the common steel grade of China and other countries in the 15 th gear material of the gear handbook and the heat treatment table thereof, and according to the material composition (which can be approximately regarded as 25Cr3 Mo) of the material 722M24 in the continuous table 2.12.1-1 of the world standard steel grade handbook, is closest to 25Cr2Mo1VA in GB/T3077-1999 (mainly looking at Cr and Mo elements with relatively large C content and relatively large influence on mechanical properties), UTS of the 25Cr2Mo1VA in GB/T3077-1999 is 735MPa.
According to the elastic modulus and Poisson ratio of materials 1-1-6 in volume 1 of the mechanical design manual, the elastic modulus value of nickel-chromium steel and alloy steel is 206GPa, the Poisson ratio value is 0.25-0.3, and according to the experience of calculating gears for a long time, the elastic modulus values of BS 970G 655M13 and BS 970G 722M24T are 206GPa, and the Poisson ratio value is 0.3.
The tensile strength (UTS) and elastic modulus E and Poisson' S ratio μ of materials BS 970G 655M13 and BS 970G 722M24T were input into FE-SAFE, and the S-N curve of the material of FIG. 3 was obtained using the Seeger material approximation algorithm.
S5, modeling analysis: and (3) establishing a gearbox operation model, and acquiring stress states of different positions on the gear surface in the dynamic meshing process of the gear by adopting stress simulation analysis.
The three-dimensional simplified model of the planetary gearbox is built by the Kisssoft gear drive design software through the basic parameters in Table 2 and the planetary package data obtained by mapping the CRF circulating water pump gearbox by Dacron of Zhengzhou mechanical study in 1999. The model is formed by copying various data of the actually operated planetary gear box.
Because the structure complexity of the gear box system and the states of all gears are herringbone teeth, the systematic modeling simulation difficulty is extremely high, and in order to further ensure the reliability of simulation results, a simplified analysis method is adopted for simulation, specifically, the whole planetary transmission gear box is divided into a sun gear-planet gear meshing structure and a planet gear-inner gear ring meshing structure according to the meshing effect of all gears, and then stress simulation analysis is carried out on the two partial meshing structures.
Simulation analysis of sun wheel and planet wheel:
the extracted three-dimensional analysis model of the sun gear and the planet gear and the discretized calculation model are shown in fig. 4, wherein in order to better show the stress state when the gear teeth are meshed, the meshing gear tooth areas of the sun gear and the planet gear are respectively subjected to refinement treatment of calculation model grids, as shown in fig. 5-6, the sun gear is taken as an example, the meshing is used for locally refining grids on the gear tooth structure, and the non-meshing gear teeth are subjected to discretization treatment of normal calculation grids.
And a rotating speed is applied to the planet wheel, and the sun wheel and the planet wheel are in meshed association through applying contact constraint.
Selecting a tooth surface friction coefficient: according to the lubrication and cooling 2.3 mixed lubrication of the 16 th gear device of the gear manual, the fact that most closed gear transmission belongs to the lubrication state (mixed lubrication) is pointed out, the friction coefficient of the mixed lubrication is 0.03-0.07, and the friction coefficient between a sun gear and a planet gear is 0.05 according to long-term calculation experience.
The simulation result of the stress under the meshing of the sun wheel and the planet wheel structure is as follows:
TABLE 3 simulation results of stress under sun-planet structure engagement
| Time step | Maximum stress Mpa of sun wheel-planet wheel |
| 1 | 286.05 |
| 2 | 327.4 |
| 3 | 379.86 |
| 4 | 316.68 |
| 5 | 234.47 |
| 6 | 292.12 |
| 7 | 366.67 |
Planet wheel-inner gear ring simulation analysis
The extracted planetary gear-annular gear three-dimensional analysis model and discretized calculation model are shown in fig. 7, wherein in order to better show the stress state when the gear teeth are meshed, the annular gear and the planetary gear meshing gear tooth areas are respectively subjected to refinement treatment of calculation model grids, the annular gear is taken as an example, as shown in fig. 8-9, the meshing is performed on the local refinement of grids on the gear tooth structure, and the non-meshing gear teeth are subjected to discretization treatment of normal calculation grids.
And a rotating speed is applied to the inner gear ring, and the planetary gears and the inner gear ring are in meshed connection through applying contact constraint.
The stress simulation result under the meshing of the planet wheel-inner gear ring structure is as follows:
TABLE 4 simulation results of stress under planetary gear-ring gear structure engagement
| Time step | Maximum stress Mpa of planet wheel-inner gear ring |
| 1 | 235.6 |
| 2 | 219.75 |
| 3 | 251.75 |
| 4 | 227.73 |
| 5 | 190.22 |
| 6 | 196.24 |
| 7 | 207.63 |
S6, fatigue life calculation: the life at fatigue fracture of each component gear in the gear set was calculated separately by:
wherein, the stress level progression of the l-amplitude load;
n i -number of cycles at each stress level;
N i -a limit number of cycles at which fatigue failure of the material occurs at each stress level;
d-total fatigue damage;
n-fatigue life;
t s -simulation time in seconds;
t-fatigue life time, unit year;
according to the method, the service life of gears of all parts in the gear set can be calculated respectively according to the material properties, the surface friction states and other conditions of different gear parts, and meanwhile stress states of different positions of the surfaces of the gears can be obtained.
Technical parameters of the gear set: the sun wheel and the planet wheel are made of BS 970G 655M13, the heat treatment process is surface carburization quenching, the tensile strength UTS is 930MPa, the elastic modulus E is 206GPa, and the Poisson ratio is 0.3; the material selected for the inner gear ring is BS 970G 722M24T, the heat treatment process is surface nitriding, the tensile strength UTS is 735MPa, the elastic modulus E is 206GPa, and the Poisson ratio is 0.3.
The software prediction results are analyzed and calculated according to ANSYS/FE-SAFE software:
when the use coefficient ka=1.7, the predicted lifetime of the sun gear was 235366.938 hours, the unit was converted into years, and the predicted lifetime was 26.9 years.
When the use coefficient ka=1.6, the predicted lifetime of the sun gear was 243540.579 hours, the unit was converted into years, and the predicted lifetime was 27.8 years.
The predicted lifetime of the planet wheel is 245489.266 hours, the unit is converted into years, and the predicted lifetime is 28.0 years when the use coefficient ka=1.7.
The predicted lifetime of the planet wheel is 258876.347 hours when the use coefficient ka=1.6, the unit is converted into years, and the predicted lifetime is 29.6 years.
The predicted life of the ring gear was 229132.672 hours, the unit was converted into years, and the predicted life was 26.1 years, when the use coefficient ka=1.7.
The predicted life of the ring gear was 239570.588 hours, the unit was converted into years, and the predicted life was 27.3 years, when the use coefficient ka=1.6.
Taking the service life of the worst parts, the predicted service life of the internal gear of the gear box of the whole CRF circulating water pump is 26.1-26.9 years.
Further, other factors can be added to further estimate the service life of the gearbox based on the prediction.
Gear life at different gear surface roughness: the following data are calculated for a use factor KA of 1.7.
The change in lubrication state of the gear will contact the change in the roughness of the tooth surface, thereby causing gear failure. Here, the fatigue life of the gear at different roughness is used to reflect the effect of the gear lubrication state on the gear life. According to the CRF circulating water pump gear box gear transient model and the finite element analysis result, the service life of each gear under different surface roughness can be calculated by inputting different roughness values into the FE-SAFE, as shown in table 5 and figure 10.
TABLE 5 fatigue life of individual gears at different roughness
The roughness Rz6.3 corresponds to Ra0.8 or Ra1.6, and is the tooth surface finish achieved by gear grinding in a general state. According to years of experience of mapping foreign gears and experience of gear grinding processing, taking the gear roughness state of the CRF gear box when leaving the factory as Rz6.3.
As can be seen from the results of the calculation, the predicted lifetime of the gear gradually decreases as the surface roughness increases; and the trend of reduction in predicted life of the three gears is consistent.
Claims (5)
1. The method for evaluating the operational state of the important pump gearbox of the nuclear power plant is characterized by comprising the following steps of:
s1, detecting the surface morphology of gears of an important pump gear box regularly, judging whether the gears fail according to failure standards, and if the failure standards are met, replacing new gears; if the failure standard is not met, the next step is carried out;
s2, building a material cyclic stress strain curve: according to the actual material and surface treatment state of the on-site used gear, establishing a cyclic stress-strain curve of the top point of the hysteresis ring which is connected by taking strain epsilon as an abscissa and stress sigma as an ordinate;
s3, determining stress history: determining the load-time history of the pump motor by actually measuring the interface device or according to design parameters: when the pump set actually operates, the interface equipment is actually measured to transmit torque and data of transient change at the initial stage of starting the pump, and the torque transmitted to the gear pair is calculated; meanwhile, according to gear design experience data, a start-stop impact use coefficient and a gear pair load non-uniformity coefficient, a pump motor load-time history is obtained, and according to a gear dangerous point position, the load-time history is converted into a local stress-time history of the gear dangerous point position according to a cyclic stress-strain curve;
s4, drawing an S-N curve: manufacturing a test piece consistent with a gear of the gear box, performing a fatigue test, measuring the number N of cycles when the test piece breaks, and drawing an S-N curve;
s5, modeling analysis: establishing a gear box operation model, dividing the gear box into at least two partial meshing structures according to the meshing action of each gear, respectively calculating the service life of each component gear in the gear set when in fatigue fracture according to the material properties and surface friction state conditions of different gear components, and simultaneously obtaining stress states of different positions of the gear surface;
s6, fatigue life calculation: the life at fatigue fracture of each component gear in the gear set was calculated separately by:
wherein, the stress level progression of the l-amplitude load;
n i -number of cycles at each stress level;
N i -a limit number of cycles at which fatigue failure of the material occurs at each stress level;
d-total fatigue damage;
n-fatigue life;
t s -simulation time in seconds;
t-fatigue life time, unit year.
2. The method for evaluating the operational state of a gear box of an important pump of a nuclear power plant according to claim 1,
the method is characterized in that in the step S5, stress states of different positions on the gear surface in the dynamic meshing process of the gear are obtained by adding simulation analysis under different gear surface roughness.
3. The method for evaluating the operational status of a gear box of an important pump of a nuclear power plant according to claim 1 or 2, wherein in the step S2, the surface treatment status of the gear is obtained by metallographic structure sampling analysis.
4. The method for evaluating the operational status of a gear box of an important pump of a nuclear power plant according to claim 1 or 2, wherein in the step S4, an S-N curve is drawnFinger means: performing fatigue test on the test piece under a certain average stress sigma m Or applying different stress amplitudes under a certain cyclic characteristic R, and measuring the cyclic number N of the test piece when the test piece breaks; sigma of max And (3) drawing points and connecting to obtain corresponding S-N curves by taking the ordinate and the N as the abscissa.
5. The method for evaluating the operational status of a gearbox of an important pump of a nuclear power plant according to claim 1 or 2, wherein in the step S5, the establishing a gearbox operational model is: and establishing a three-dimensional model of the operation of the gear box by adopting a finite element method according to the design or actual measurement parameters of the gear box.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103018063A (en) * | 2012-11-27 | 2013-04-03 | 河海大学 | Bridge random fatigue life prediction method based on Mittag-Leffler distribution |
| CN104268335A (en) * | 2014-09-23 | 2015-01-07 | 工业和信息化部电子第五研究所 | Vibration fatigue life predication method and system for micro-packaging assembly |
| CN108263639A (en) * | 2018-01-28 | 2018-07-10 | 北京工业大学 | Aircaft configuration key position fatigue life on-line monitoring method based on indirect measuring strain under spectrum carries |
| CN109299559A (en) * | 2018-10-08 | 2019-02-01 | 重庆大学 | A kind of Surface hardened layer gear wear and fatigue failure competition mechanism analysis method |
| CN110147624A (en) * | 2019-05-24 | 2019-08-20 | 重庆大学 | A kind of Gear Contact Prediction method for fatigue life based on loading spectrum |
| CN111339700A (en) * | 2020-02-19 | 2020-06-26 | 广东核电合营有限公司 | Method and device for evaluating fatigue damage of nuclear turbine blade and storage medium |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10620621B2 (en) * | 2016-03-25 | 2020-04-14 | Hitachi, Ltd. | Remaining life assessment apparatus and method as well as wind turbine generator system |
-
2020
- 2020-11-27 CN CN202011364733.5A patent/CN112487580B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103018063A (en) * | 2012-11-27 | 2013-04-03 | 河海大学 | Bridge random fatigue life prediction method based on Mittag-Leffler distribution |
| CN104268335A (en) * | 2014-09-23 | 2015-01-07 | 工业和信息化部电子第五研究所 | Vibration fatigue life predication method and system for micro-packaging assembly |
| CN108263639A (en) * | 2018-01-28 | 2018-07-10 | 北京工业大学 | Aircaft configuration key position fatigue life on-line monitoring method based on indirect measuring strain under spectrum carries |
| CN109299559A (en) * | 2018-10-08 | 2019-02-01 | 重庆大学 | A kind of Surface hardened layer gear wear and fatigue failure competition mechanism analysis method |
| CN110147624A (en) * | 2019-05-24 | 2019-08-20 | 重庆大学 | A kind of Gear Contact Prediction method for fatigue life based on loading spectrum |
| CN111339700A (en) * | 2020-02-19 | 2020-06-26 | 广东核电合营有限公司 | Method and device for evaluating fatigue damage of nuclear turbine blade and storage medium |
Non-Patent Citations (3)
| Title |
|---|
| 中华人民共和国国家发展和改革委员会.重载齿轮失效判据.中华人民共和国机械行业标准JB/T5664-2007.2007,全文. * |
| 杨志凌等.基于CAE软件的风电机组齿轮疲劳寿命预测.计算机仿真.2015,第162-169页. * |
| 郦明等.双参数统计计数法.结构抗疲劳设计.1987,全文. * |
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