CN109726411B - Method for calculating fatigue strength of cabin structure of wind turbine - Google Patents
Method for calculating fatigue strength of cabin structure of wind turbine Download PDFInfo
- Publication number
- CN109726411B CN109726411B CN201711042092.XA CN201711042092A CN109726411B CN 109726411 B CN109726411 B CN 109726411B CN 201711042092 A CN201711042092 A CN 201711042092A CN 109726411 B CN109726411 B CN 109726411B
- Authority
- CN
- China
- Prior art keywords
- stress
- fatigue
- load
- wind turbine
- damage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 36
- 239000000463 material Substances 0.000 claims abstract description 22
- 238000004364 calculation method Methods 0.000 claims abstract description 20
- 238000001228 spectrum Methods 0.000 claims abstract description 16
- 238000004458 analytical method Methods 0.000 claims abstract description 7
- 230000005484 gravity Effects 0.000 claims abstract description 6
- 239000011159 matrix material Substances 0.000 claims description 9
- 238000001514 detection method Methods 0.000 claims description 3
- 230000002123 temporal effect Effects 0.000 claims description 3
- 230000001186 cumulative effect Effects 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 description 1
Abstract
The invention belongs to the technical field of calculation of fatigue strength of a wind turbine cabin structure, in particular relates to a calculation method of fatigue strength of a wind turbine cabin structure, and aims to solve the problems that in the past, fatigue strength influence factors are not fully considered, fatigue damage calculation is inaccurate and the like in the calculation process, a unit load component and a generator gravity working condition stress result are obtained through a finite element analysis method, a stress time sequence is obtained through combining a fatigue time sequence, a stress spectrum is obtained through a rain flow counting method, S-N curve families under different stress ratios of materials are established, and finally final damage is calculated through a Miner linear cumulative damage theory. The method is characterized in that: it includes the determination of stress spectrum; calculating S-N curve families of the material under different stress ratios; and checking the fatigue strength of the cabin structure. The method is more accurate and more suitable for actual load working conditions, can more accurately analyze fatigue damage of the nacelle structure of the wind turbine, and improves the running safety and reliability of wind turbine equipment.
Description
Technical Field
The invention belongs to the technical field of calculation of fatigue strength of a wind turbine cabin structure, and particularly relates to a calculation method of fatigue strength of a wind turbine cabin structure.
Background
The cabin structure is one of the most critical and most complex bearing components in the permanent magnet direct drive wind generating set, and the design reliability directly influences the running safety of the set. In hundreds of wind power accidents at home and abroad in the past decade, most of the wind power accidents are caused by fatigue failure. The design life of a wind turbine is usually 20 years, and the wind turbine must bear alternating stress generated by alternating load and possibly fatigue damage in the design life, so that the safety and reliability of the wind turbine generator set must be checked by scientific and standard calculation.
When the fatigue strength analysis is carried out on the wind turbine cabin structure in the past, the consideration of factors influencing the structural fatigue strength performance is incomplete, the external load only considers the load under the fixed coordinate system of the hub center, the SN curve only adopts the SN curve of one standard sample, and the calculation result is inaccurate and unreliable.
Disclosure of Invention
The invention aims to enable fatigue check of a nacelle structure of a wind turbine to be more accurate and reliable, solve the problems of incomplete consideration of fatigue strength influence factors, inaccurate fatigue damage calculation and the like in the traditional calculation process, obtain stress results under unit load components and generator gravity load through a finite element analysis method, obtain stress time sequence through combining fatigue time sequence, obtain stress spectrum through a rain flow counting method, establish S-N curve families under different stress ratios of materials, and finally calculate final damage through a Miner linear cumulative damage theory.
The invention is realized in the following way:
a calculation method for fatigue strength of a wind turbine cabin structure specifically comprises the following steps:
step one: determination of stress spectrum
Firstly, obtaining a linear relation between load and part stress; the stress time course is calculated by adopting a finite element analysis method, namely, the linear product of the finite element calculation result of the structural unit load and the gravity load of the generator and the time load course is used for calculating the stress time course, and the stress formula of the wind turbine cabin structure is as follows:
σx(t)＝SxFx*Fx(t)+SxFy*Fy(t)+SxFz*Fz(t)+SxMx*Mx(t)+SxMy*My(t)+SxMz*Mz(t)+SxG
σy(t)＝SyFx*Fx(t)+SyFy*Fy(t)+SyFz*Fz(t)+SyMx*Mx(t)+SyMy*My(t)+SyMz*Mz(t)+SyG
σz(t)＝SzFx*Fx(t)+SzFy*Fy(t)+SzFz*Fz(t)+SzMx*Mx(t)+SzMy*My(t)+SzMz*Mz(t)+SzG
τxy(t)＝SxyFx*Fx(t)+SxyFy*Fy(t)+SxyFz*Fz(t)+SxyMx*Mx(t)+SxyMy*My(t)+SxyMz*Mz(t)+SxyG
τyz(t)＝SyzFx*Fx(t)+SyzFy*Fy(t)+SyzFz*Fz(t)+SyzMx*Mx(t)+SyzMy*My(t)+SyzMz*Mz(t)+SyzG
τxz(t)＝SxzFx*Fx(t)+SxzFy*Fy(t)+SxzFz*Fz(t)+SxzMx*Mx(t)+SxzMy*My(t)+SxzMz*Mz(t)+SxzG
wherein: σx, σy, σz, τxy, τyz, τxz are stress components; fx (t), fy (t), fz (t), mx (t), my (t), mz (t) are temporal load history components; others are finite element stress component results;
determining the average stress and the stress range of each stress cycle by using a rain flow counting method through Ncode software, and finally determining a stress spectrum, namely a matrix relation of one-to-one correspondence of the average stress, the stress amplitude and the cycle number;
step two: calculating S-N curve family of material under different stress ratios
According to GL2010 specifications, determining an S-N curve family of the corresponding material, wherein a specific formula refers to the content in a fifth chapter annex B in the specifications; all the formulas are programmed into excel for presentation; wherein the wall thickness of the structure is input according to the maximum thickness, and the tensile strength and the yield strength of the material are referred to accessory related standards; roughness, quality level and flaw detection method refer to relevant standards, and in order to obtain S-N curves under different stress ratios, the stress ratio is taken as a value: 0.5,0.25,0, -0.5, -1, -2, etc.; finally, an S-N curve family of the cabin structural material under different stress ratios is obtained, as shown in figure 1;
step three: cabin structural fatigue strength check
Converting a stress spectrum into full cycle times under each stress level by a rain flow counting method by combining a material S-N curve family synthesized according to specifications to obtain a rain flow matrix, comparing the rain flow matrix with the material S-N curve family, performing interpolation calculation on adjacent curves which are not on stress ratio curves, extracting different types of stresses in a cabin structure by adopting an absolute value maximum principal stress method, a signed mises stress method and a critical plane method, and finally calculating a damage value; calculating the fatigue life according to the fatigue accumulated damage theory, wherein the fatigue algorithm adopted is a Miner linear accumulated damage theory; the total fatigue damage is:
wherein the method comprises the steps of
d i -damage under i-th class load;
m-total number of load levels in the load spectrum;
n i -number of actions of the i-th stage load;
N i -number of permitted roles of the i-th stage load.
The beneficial effects of the invention are as follows:
when the fatigue strength analysis is carried out on the wind turbine cabin structure in the past, the consideration of factors influencing the structural fatigue strength performance is incomplete, the external load only considers the load under the fixed coordinate system of the hub center, the SN curve only adopts the SN curve of one standard sample, and the calculation result is inaccurate and unreliable. According to the invention, external wind load is considered, the gravity influence of the generator is also considered, an S-N curve family under the multi-stress ratio which can clearly represent the cabin structural material is used, and finally the fatigue damage of the cabin structure is calculated through an absolute value maximum main stress method, a signed mises stress method and a critical plane method. The fatigue damage of the wind turbine cabin structure can be accurately analyzed more accurately and more closely fit with the actual load working condition, and the running safety and reliability of wind turbine equipment are improved.
Drawings
FIG. 1 is a family of S-N curves for multiple stress ratios.
Detailed Description
The invention is further described below with reference to the drawings and examples.
A method for calculating fatigue strength of a nacelle structure of a wind turbine comprises the following steps:
step one: determination of stress spectrum
Linear fatigue refers to fatigue caused by a load time series under the condition that the stress magnitude of a part linearly changes with the external load magnitude. Wind turbine nacelle structural fatigue is a type of fatigue. First, a linear relationship between load and part stress is obtained. The stress time course is generally calculated by adopting a finite element analysis method, namely, the linear product of the finite element calculation result under the structural unit load and the gravity load of the generator and the time load course is utilized to calculate the stress time course, and the stress formula of the wind turbine cabin structure is as follows (the calculation formula is compiled by the inventor according to specific working conditions).
σx(t)＝SxFx*Fx(t)+SxFy*Fy(t)+SxFz*Fz(t)+SxMx*Mx(t)+SxMy*My(t)+SxMz*Mz(t)+SxG
σy(t)＝SyFx*Fx(t)+SyFy*Fy(t)+SyFz*Fz(t)+SyMx*Mx(t)+SyMy*My(t)+SyMz*Mz(t)+SyG
σz(t)＝SzFx*Fx(t)+SzFy*Fy(t)+SzFz*Fz(t)+SzMx*Mx(t)+SzMy*My(t)+SzMz*Mz(t)+SzG
τxy(t)＝SxyFx*Fx(t)+SxyFy*Fy(t)+SxyFz*Fz(t)+SxyMx*Mx(t)+SxyMy*My(t)+SxyMz*Mz(t)+SxyG
τyz(t)＝SyzFx*Fx(t)+SyzFy*Fy(t)+SyzFz*Fz(t)+SyzMx*Mx(t)+SyzMy*My(t)+SyzMz*Mz(t)+SyzG
τxz(t)＝SxzFx*Fx(t)+SxzFy*Fy(t)+SxzFz*Fz(t)+SxzMx*Mx(t)+SxzMy*My(t)+SxzMz*Mz(t)+SxzG
Wherein: σx, σy, σz, τxy, τyz, τxz are stress components; fx (t), fy (t), fz (t), mx (t), my (t), mz (t) are temporal load history components; others are finite element stress component results.
Fatigue loading spectra are typically determined using a cycle count method. There are tens of methods available for cycle counting, with the most widely used being the rain flow counting method. The method has sufficient mechanical basis and high accuracy, and the average stress and the stress range of each stress cycle are determined by using a rain flow counting method through Ncode software, so that the stress spectrum, namely the matrix relation of one-to-one correspondence of the average stress, the stress amplitude and the cycle number is finally determined.
Step two: calculating S-N curve family of material under different stress ratios
According to the GL2010 specification, an S-N curve family of the corresponding material is determined, a specific formula refers to the content in an annex B of a fifth chapter in the specification, and all the used formulas are programmed into excel for calculation convenience and are presented. Wherein the wall thickness of the structure is input according to the maximum thickness, and the tensile strength and the yield strength of the material are referred to accessory related standards; roughness, quality level and flaw detection method refer to relevant standards, and in order to obtain S-N curves under different stress ratios, the stress ratio is taken as a value: 0.5,0.25,0, -0.5, -1, -2, etc. Finally, an S-N curve family of the cabin structural material under different stress ratios is obtained, as shown in figure 1.
Step three: cabin structural fatigue strength check
And combining a material S-N curve family synthesized according to specifications, converting a stress spectrum into full cycle times under each stress level through a rain flow counting method to obtain a rain flow matrix, comparing the rain flow matrix with the material S-N curve family, performing interpolation calculation on adjacent curves which are not on stress ratio curves, respectively extracting different types of stresses in a cabin structure by adopting an absolute value maximum principal stress method, a signed mises stress method and a critical plane method, and finally calculating a damage value. And (3) calculating the fatigue life according to the fatigue cumulative damage theory, wherein the fatigue algorithm adopted is the Miner linear cumulative damage theory. The total fatigue damage is:
wherein the method comprises the steps of
d i -damage under i-th class load;
m-total number of load levels in the load spectrum;
n i -number of actions of the i-th stage load;
N i -number of permitted roles of the i-th stage load.
The embodiment of the present invention has been described in detail with reference to the embodiments, but the present invention is not limited to the embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention. The invention may be practiced otherwise than as specifically described in the specification.
Claims (1)
1. A method for calculating fatigue strength of a nacelle structure of a wind turbine comprises the following steps:
step one: determination of stress spectrum
Firstly, obtaining a linear relation between load and part stress; the method is used for calculating by adopting a finite element analysis method, namely calculating the stress time course by utilizing the linear product of the finite element calculation result under the structural unit load and the gravity load of the generator and the time load course, and the stress formula of the wind turbine cabin structure is as follows:
σx(t)＝SxFx*Fx(t)+SxFy*Fy(t)+SxFz*Fz(t)+SxMx*Mx(t)+SxMy*My(t)+SxMz*Mz(t)+SxG
σy(t)＝SyFx*Fx(t)+SyFy*Fy(t)+SyFz*Fz(t)+SyMx*Mx(t)+SyMy*My(t)+SyMz*Mz(t)+SyG
σz(t)＝SzFx*Fx(t)+SzFy*Fy(t)+SzFz*Fz(t)+SzMx*Mx(t)+SzMy*My(t)+SzMz*Mz(t)+SzG
τxy(t)＝SxyFx*Fx(t)+SxyFy*Fy(t)+SxyFz*Fz(t)+SxyMx*Mx(t)+
SxyMy*My(t)+SxyMz*Mz(t)+SxyG
τyz(t)＝SyzFx*Fx(t)+SyzFy*Fy(t)+SyzFz*Fz(t)+SyzMx*Mx(t)+
SyzMy*My(t)+SyzMz*Mz(t)+SyzG
τxz(t)＝SxzFx*Fx(t)+SxzFy*Fy(t)+SxzFz*Fz(t)+SxzMx*Mx(t)+
SxzMy*My(t)+SxzMz*Mz(t)+SxzG
wherein: σx, σy, σz, τxy, τyz, τxz are stress components; fx (t), fy (t), fz (t), mx (t), my (t), mz (t) are temporal load history components; others are finite element stress component results;
determining the average stress and the stress range of each stress cycle by using a rain flow counting method through Ncode software, and finally determining a stress spectrum, namely a matrix relation of one-to-one correspondence of the average stress, the stress amplitude and the cycle number;
step two: calculating S-N curve family of material under different stress ratios
According to GL2010 specifications, determining an S-N curve family of the corresponding material, wherein a specific formula refers to the content in a fifth chapter annex B in the specifications; all the formulas are programmed into excel for presentation; the wall thickness of the structure is input according to the maximum thickness, and the tensile strength and the yield strength of the material meet the national standard; the roughness, the quality level and the flaw detection method meet the national standard, and the stress ratio is taken as a value for obtaining S-N curves under different stress ratios: 0.5,0.25,0, -0.5, -1, -2; finally, an S-N curve family of the cabin structural material under different stress ratios is obtained;
step three: cabin structural fatigue strength check
Converting a stress spectrum into full cycle times under each stress level by a rain flow counting method by combining a material S-N curve family synthesized according to specifications to obtain a rain flow matrix, comparing the rain flow matrix with the material S-N curve family, performing interpolation calculation on adjacent curves which are not on stress ratio curves, extracting different types of stresses in a cabin structure by adopting an absolute value maximum principal stress method, a signed mises stress method and a critical plane method, and finally calculating a damage value; calculating the fatigue life according to the fatigue accumulated damage theory, wherein the fatigue algorithm adopted is a Miner linear accumulated damage theory; the total fatigue damage is:
wherein the method comprises the steps of
d i -damage under i-th class load;
m-total number of load levels in the load spectrum;
n i -number of actions of the i-th stage load;
N i -number of permitted roles of the i-th stage load.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711042092.XA CN109726411B (en) | 2017-10-31 | 2017-10-31 | Method for calculating fatigue strength of cabin structure of wind turbine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711042092.XA CN109726411B (en) | 2017-10-31 | 2017-10-31 | Method for calculating fatigue strength of cabin structure of wind turbine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109726411A CN109726411A (en) | 2019-05-07 |
| CN109726411B true CN109726411B (en) | 2024-04-02 |
Family
ID=66292906
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711042092.XA Active CN109726411B (en) | 2017-10-31 | 2017-10-31 | Method for calculating fatigue strength of cabin structure of wind turbine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109726411B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110991111B (en) * | 2019-11-27 | 2024-01-30 | 南京安维士传动技术股份有限公司 | Wind power gear box planet carrier fatigue calculation method based on friction contact |
| CN111914355B (en) * | 2020-07-23 | 2023-07-18 | 中车唐山机车车辆有限公司 | Rail vehicle welding structure stress factor determining method and device and terminal equipment |
| CN113177331A (en) * | 2021-06-04 | 2021-07-27 | 中国船舶重工集团海装风电股份有限公司 | SN curve automatic generation method and system based on specific data model |
| CN113357099B (en) * | 2021-06-07 | 2022-09-06 | 浙江大学 | Fatigue diagnosis and detection method for fan tower drum based on acceleration sensor |
| CN115169203B (en) * | 2022-09-09 | 2022-11-25 | 长江勘测规划设计研究有限责任公司 | Method for evaluating fatigue strength of welding seam of ship lift in complex welding structure |
| CN117077273B (en) * | 2023-10-18 | 2024-02-20 | 中国船舶集团风电发展有限公司 | Fatigue strength calculation method for tower barrel bearing platform of wind turbine generator |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104792633A (en) * | 2015-04-17 | 2015-07-22 | 中国商用飞机有限责任公司北京民用飞机技术研究中心 | Prediction method of crack propagation life of aircraft body |
| KR101706508B1 (en) * | 2016-07-12 | 2017-02-16 | 한국에너지기술연구원 | Data Analysis System of Mechanical Load Measurement Data for Wind Turbine |
-
2017
- 2017-10-31 CN CN201711042092.XA patent/CN109726411B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104792633A (en) * | 2015-04-17 | 2015-07-22 | 中国商用飞机有限责任公司北京民用飞机技术研究中心 | Prediction method of crack propagation life of aircraft body |
| KR101706508B1 (en) * | 2016-07-12 | 2017-02-16 | 한국에너지기술연구원 | Data Analysis System of Mechanical Load Measurement Data for Wind Turbine |
Non-Patent Citations (5)
| Title |
|---|
| K Hammerum et al..A fatigue approach to wind turbine control.Journal of Physics: Conference Series.2007,全文. * |
| 吴树梁 ; 于良峰 ; 李钢强 ; .水平轴风电机组轮毂疲劳损伤计算方法.风机技术.(第03期),全文. * |
| 晏红文 ; 田红旗 ; 钟杰 ; 吕杏梅 ; 杨兆忠 ; .风力发电机组大型铸件多轴疲劳计算.机械设计.(第09期),全文. * |
| 牛牧华 ; 陈程 ; .变截面纤维增强塑料梁结构的疲劳寿命分析方法.玻璃钢/复合材料.(第01期),全文. * |
| 陈严 ; 张林伟 ; 刘雄 ; 叶枝全 ; .水平轴风力机叶片疲劳载荷的计算分析.太阳能学报.(第05期),全文. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109726411A (en) | 2019-05-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109726411B (en) | Method for calculating fatigue strength of cabin structure of wind turbine | |
| CN109344553B (en) | Method for predicting structure detail life under action of high-low cycle composite fatigue loads | |
| CN107742025B (en) | Method for predicting fatigue life of airplane metal skin after impact | |
| CN101408951B (en) | Method for obtaining equivalent load spectrum and estimating weariness residual longevity of bridge crane based on neural network | |
| CN102324040B (en) | Methods for acquiring equivalent load spectrum and estimating residual fatigue life of bridge crane | |
| CN104156599B (en) | A kind of accelerated life test loading spectrum considering many mechanism determines method | |
| CN104809321A (en) | Method for analyzing service life of high maneuverability aircraft base on detail fatigue rating | |
| CN111090957B (en) | Dangerous point stress-strain calculation method for high-temperature structure | |
| AU2019436655B2 (en) | Dynamic reliability evaluation method for coupling faults of middle trough of scraper conveyor | |
| CN102645365B (en) | Method for determining range of effective stress intensity factor | |
| CN106441851A (en) | Method for detecting fatigue life of mechanical part | |
| CN104155092B (en) | Wind turbine blade static analysis method | |
| CN108052717B (en) | Fatigue life calibration method based on local stress-strain method | |
| CN115130495A (en) | Rolling bearing fault prediction method and system | |
| CN106548009B (en) | Method and device for evaluating power impact effect of goaf power transmission tower | |
| CN107169187A (en) | A kind of ocean platform weight predictor method | |
| CN109101750B (en) | Accelerated life prediction method for electronic device in damp and hot environment | |
| CN106089790A (en) | Pump shaft and lower half a coupler symmetric double key fit key technique under core main pump | |
| CN108169013B (en) | Fatigue life calibration method suitable for multi-nail connection test piece | |
| CN110287619B (en) | Multi-axis random load fatigue life prediction method | |
| CN114139276A (en) | Fatigue life analysis method for disk-shaft integrated blisk structure | |
| CN103344385A (en) | Crankshaft dynamic balance acquisition method based on finite elements | |
| CN102506806B (en) | Strain calculating method for transmission tower real-model test | |
| CN103678775A (en) | Delivery pipe dynamic strength analysis method | |
| CN104972423A (en) | Bolt screwing detection method, device and system and hydraulic wrench |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |