CN106777479B - Turbine blade nonlinear creep analysis method based on beam theory - Google Patents
Turbine blade nonlinear creep analysis method based on beam theory Download PDFInfo
- Publication number
- CN106777479B CN106777479B CN201611018355.9A CN201611018355A CN106777479B CN 106777479 B CN106777479 B CN 106777479B CN 201611018355 A CN201611018355 A CN 201611018355A CN 106777479 B CN106777479 B CN 106777479B
- Authority
- CN
- China
- Prior art keywords
- creep
- turbine blade
- time
- point
- stress
- 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
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/17—Mechanical parametric or variational design
Abstract
The invention discloses a turbine blade nonlinear creep analysis method based on a beam theory, which comprises the following steps of: a. determining material creep parameters at a plurality of temperatures within a turbine blade operating range; b. dividing the operating time of the turbine blade into a plurality of time steps; c. selecting a plurality of sections of the turbine blade and dividing the sections into grids; d. acquiring the creep stress and the permanent damage of the blade at each time step after the creep and the creep relaxation based on a beam theory; e. and acquiring the creep elongation and creep lasting damage of the blade. The main factors of the creep of the turbine blade are considered, the acquisition is convenient and fast, the precision can meet the practical engineering requirements, the acquisition efficiency is improved by hundreds of times, the method is suitable for multi-scheme blade comparison analysis, full-life blade creep analysis and online life monitoring of the turbine blade, and the engineering practicability is better. The creep elongation and the endurance life of the multi-type engine turbine blade are analyzed and verified, and engine long test results show that the acquired data precision can meet engineering practical requirements.
Description
Technical Field
The invention relates to the technical field of detection and calibration of turbine blades of aero-engines, in particular to a nonlinear creep analysis method of a turbine blade based on a beam theory.
Background
The turbine blade is the worst part of the working environment in the engine, the creep deformation and creep rupture of the turbine blade are important failure modes of the turbine blade, and the creep analysis of the turbine blade is important content of the engine design and the outfield monitoring. Creep is a non-linear deformation that increases with time, and blade creep is related to operating temperature, stress level, and duration.
The conventional blade creep analysis generally adopts a universal three-dimensional finite element method, creep is considered in a constitutive equation, and the creep of a structure is simulated through material creep parameters, discretized structural rigidity and application of corresponding boundary conditions. The three-dimensional finite element creep analysis is long in time consumption and low in efficiency, and is difficult to adapt to the requirements of blade design analysis and blade service life monitoring of multiple schemes, multiple working conditions and long service life.
Disclosure of Invention
The invention provides a turbine blade nonlinear creep analysis method based on a beam theory, and aims to solve the technical problems that the existing three-dimensional finite element creep analysis is long in time consumption and low in efficiency, and is difficult to adapt to multi-scheme, multi-working-condition and long-service-life blade design analysis and real-time monitoring of the service life of a blade.
The invention provides a turbine blade nonlinear creep analysis method based on a beam theory, which comprises the following steps of: a. determining material creep parameters at a plurality of temperatures within a turbine blade operating range; b. dividing the operating time of the turbine blade into a plurality of time steps; c. selecting a plurality of sections of the turbine blade and dividing the sections into grids; d. acquiring the creep stress and the permanent damage of the blade at each time step after the creep and the creep relaxation based on a beam theory; e. and acquiring the creep elongation and creep lasting damage of the blade.
Further, the specific implementation steps of the step a are as follows: determining the material creep equation parameters of at least three temperatures in the working temperature range of the blade, wherein the material creep equation at the specific temperature is
εc＝Aσmtp
Wherein A is constant, m is stress index, p is temperature index, A, m, p are determined by material creep test curve, epsiloncFor creep strain, σ is stress, and t is time; creep equations at different temperatures can be obtained according to creep tests at multiple temperatures; in the case of limited material creep test data, the creep test curves are constructed according to discrete material creep limits.
Further, the specific implementation steps of step c are as follows: cutting a radial cross section along a blade body of the turbine blade, and cutting a plurality of radial cross sections along an axial direction of the blade body; dividing each radial section into a plurality of section meshes composed of triangular mesh units; nodes are formed between the adjacent triangle mesh cell handoffs.
Further, the specific implementation steps of step d are as follows: according to the plane hypothesis of the radial section, the tensile stress and the bending stress of the turbine blade at each node position of the radial section at the initial moment are obtained by adopting a beam theory and a numerical method; selecting a joint j point on a hypothetical plane, wherein the stress at the initial moment is sigmaj(0) At the lapse of 1 st period of time Δ1After t, assume that the j points are all subjected to σ in this periodj(0) Obtaining delta according to creep equation of material under action of stress1Creep strain increment at time t
Considering creep strain delta from the radial cross-sectional plane assumption
Obtaining j point total strain increment delta by adopting numerical method1εj。
Further, j point Δ1the stress increment at time t is:
wherein E isjThe modulus of elasticity at point j;
j point Δ1the stress at time t is:
σj(1)＝σj(0)+Δ1σj。
further, the stress σ according to the time i-1j(i-1) and creep equation of the material to obtain DeltaiCreep strain increment of j point corresponding to t time
Considering creep strain delta from the radial cross-sectional plane assumption
Numerically acquiring j-point total strain increaseQuantity Δiεj。
Further, Δithe j point stress increment corresponding to t is:
wherein E isjThe modulus of elasticity at point j;
the stress at time j at time i is:
σj(i)＝σj(i-1)+Δiσj。
further, acquiring the equivalent stress of a j point in the action time of the external load; acquiring creep endurance strength reserve of a j point in the action time of the external load; and acquiring creep endurance strength reserve of a j point under the combined action of a plurality of working conditions.
Further, for the nodes corresponding to the k section and the k +1 section of two adjacent radial sections, the creep elongation is as follows:
wherein epsilonk+1Is the creep amount of the corresponding point of the k +1 section, epsilonkThe amount of creep of the corresponding point of the k section, hk+1Leaf height, h, of the corresponding point of the k +1 sectionkThe leaf height of a corresponding point of the k section; the creep elongation for the overall leaf height was obtained as:
further, the specific implementation steps of step e are as follows: and d, repeating the step d to obtain the calculation results of the stress, the strength reserve and the creep elongation of each node of all the radial sections, and obtaining the lasting damage of each node of the turbine blade in the working time according to the accumulated damage principle.
The invention has the following beneficial effects:
the turbine blade nonlinear creep analysis method based on the beam theory considers the main factors of the turbine blade creep, is convenient to obtain, has the precision capable of meeting the practical engineering requirements, is higher in obtaining efficiency by hundreds of times compared with the existing three-dimensional finite element method, is suitable for multi-scheme blade comparison analysis, full-life blade creep analysis and online life monitoring of the turbine blade, and is better in engineering practicability. The creep elongation and the endurance life of the multi-type engine turbine blade are analyzed and verified by using the method, and engine long test results show that the acquired data precision can meet engineering practical requirements and the expected effect is achieved.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a flow chart illustrating the steps of a method for analyzing the nonlinear creep of a turbine blade based on the beam theory in accordance with a preferred embodiment of the present invention.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the accompanying drawings, but the invention can be embodied in many different forms, which are defined and covered by the following description.
FIG. 1 is a flow chart illustrating the steps of a method for analyzing the nonlinear creep of a turbine blade based on the beam theory in accordance with a preferred embodiment of the present invention. As shown in FIG. 1, the method for analyzing the nonlinear creep of the turbine blade based on the beam theory of the embodiment comprises the following steps: a. determining material creep parameters at a plurality of temperatures within a turbine blade operating range; b. dividing the operating time of the turbine blade into a plurality of time steps; c. selecting a plurality of sections of the turbine blade and dividing the sections into grids; d. acquiring the creep stress and the permanent damage of the blade at each time step after the creep and the creep relaxation based on a beam theory; e. and acquiring the creep elongation and creep lasting damage of the blade. Alternatively, the order of implementation of steps b and c may be reversed. The turbine blade nonlinear creep analysis method based on the beam theory considers the main factors of the turbine blade creep, is convenient to obtain, has the precision capable of meeting the practical engineering requirements, is higher in obtaining efficiency by hundreds of times compared with the existing three-dimensional finite element method, is suitable for multi-scheme blade comparison analysis, full-life blade creep analysis and online life monitoring of the turbine blade, and is better in engineering practicability. The creep elongation and the endurance life of the multi-type engine turbine blade are analyzed and verified by using the method, and engine long test results show that the acquired data precision can meet engineering practical requirements and the expected effect is achieved. The beam theory is to simplify the three-dimensional problem of the elasticity theory into a one-dimensional problem.
In this embodiment, the specific implementation steps of step a are as follows: determining the material creep equation parameters of at least three temperatures in the working temperature range of the blade, wherein the material creep equation at the specific temperature is
εc＝Aσmtp
Wherein A is constant, m is stress index, p is temperature index, A, m, p are determined by material creep test curve, epsiloncFor creep strain, σ is stress, and t is time; creep equations at different temperatures can be obtained according to creep tests at multiple temperatures; in the case of limited material creep test data, the creep test curves are constructed according to discrete material creep limits.
In this embodiment, the specific implementation steps of step c are as follows: cutting a radial cross section along a blade body of the turbine blade, and cutting a plurality of radial cross sections along an axial direction of the blade body; dividing each radial section into a plurality of section meshes composed of triangular mesh units; nodes are formed between the adjacent triangle mesh cell handoffs.
In this embodiment, the specific implementation steps of step d are as follows: according to the plane hypothesis of the radial section, the tensile stress and the bending stress of the turbine blade at each node position of the radial section at the initial moment are obtained by adopting a beam theory and a numerical method; selecting a joint j point on a hypothetical plane, wherein the stress at the initial moment is sigmaj(0) At the lapse of 1 st period of time Δ1After t, assume that the j points are all subjected to σ in this periodj(0) Obtaining delta according to creep equation of material under action of stress1At time tCreep strain increment of etching
Considering creep strain delta from the radial cross-sectional plane assumption
Obtaining j point total strain increment delta by adopting numerical method1εj。
In this embodiment, j point Δ1the stress increment at time t is:
wherein E isjThe modulus of elasticity at point j;
j point Δ1the stress at time t is:
σj(1)＝σj(0)+Δ1σj。
in this embodiment, the stress σ at the time i-1j(i-1) and creep equation of the material to obtain DeltaiCreep strain increment of j point corresponding to t time
Considering creep strain delta from the radial cross-sectional plane assumption
Obtaining j point total strain increment delta in a numerical modeiεj。
In this example,. DELTA.ithe j point stress increment corresponding to t is:
wherein E isjThe modulus of elasticity at point j;
the stress at time j at time i is:
σj(i)＝σj(i-1)+Δiσj。
in the embodiment, the equivalent stress of the j point in the action time of the external load is obtained; acquiring creep endurance strength reserve of a j point in the action time of the external load; and acquiring creep endurance strength reserve of a j point under the combined action of a plurality of working conditions.
In this embodiment, for the nodes corresponding to the k section and the k +1 section of two adjacent radial sections, the creep elongation is:
wherein epsilonk+1Is the creep amount of the corresponding point of the k +1 section, epsilonkThe amount of creep of the corresponding point of the k section, hk+1Leaf height, h, of the corresponding point of the k +1 sectionkThe leaf height of a corresponding point of the k section;
the creep elongation for the overall leaf height was obtained as:
in this embodiment, the specific implementation steps of step e are as follows: and d, repeating the step d to obtain the calculation results of the stress, the strength reserve and the creep elongation of each node of all the radial sections, and obtaining the lasting damage of each node of the turbine blade in the working time according to the accumulated damage principle.
In practice, a convenient method of turbine blade creep acquisition is provided. The main idea is as follows: dividing the working time into a plurality of time steps; acquiring the creep of the blade at each time step, stress after the creep is relaxed and permanent damage based on a beam theory; finally, the creep elongation and creep endurance damage of the blade are calculated. The method comprises the following specific steps:
(1) determining material creep equation parameters at least 3 temperatures within the working temperature range of the blade;
(2) dividing the working time into a plurality of time steps;
(3) selecting a plurality of sections of the blade and dividing the sections into grids;
(4) acquiring tensile and bending stresses of each node of the section;
(5) calculating creep strain of each node according to the temperature and the stress of the node and the time step length;
(6) acquiring node stress after creep relaxation, and acquiring creep endurance damage of a time step;
according to the steps (3) - (6), calculating creep, stress and permanent damage of each time step in the working time;
calculating the creep elongation of the blade, wherein the creep elongation is calculated according to the corresponding nodes of two adjacent sections
Creep elongation of the entire blade is
And according to the accumulated damage principle, calculating the permanent damage of each node of the blade in the working time.
The turbine blade nonlinear creep analysis method based on the beam theory is characterized in that the blade nonlinear creep based on the beam theory is obtained; acquiring a stress numerical value of the section with the irregular shape; obtaining the endurance life of the blade considering creep relaxation; acquiring creep elongation of the blade based on section strain; the foregoing calculation procedure. The method considers the main factors of blade creep, is convenient to obtain, has the precision capable of meeting the practical engineering requirements, improves the obtaining efficiency by hundreds of times compared with the existing three-dimensional finite element method, is suitable for multi-scheme blade comparative analysis, full-life blade creep analysis and online life monitoring of the turbine blade, and has better engineering practicability. By using the method, the creep elongation and the endurance life of the multi-type engine turbine blade can be obtained, and engine long-test results show that the obtained data precision can meet the practical engineering requirements, and the expected effect is achieved.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (1)
1. A turbine blade nonlinear creep analysis method based on a beam theory, which simplifies the three-dimensional problem of the elasticity theory into a one-dimensional problem, is characterized in that,
the method comprises the following steps:
a. determining material creep parameters at a plurality of temperatures within a turbine blade operating range;
b. dividing the operating time of the turbine blade into a plurality of time steps;
c. selecting a plurality of sections of the turbine blade and dividing the sections into grids;
the specific implementation steps of the step c are as follows: cutting a radial cross section along a blade body of the turbine blade, and cutting a plurality of radial cross sections along an axial direction of the blade body; dividing each radial section into a plurality of section meshes composed of triangular mesh units; nodes are formed between the adjacent triangle mesh unit handover;
d. acquiring the creep stress and the permanent damage of the blade at each time step after the creep and the creep relaxation based on a beam theory;
the specific implementation steps of the step d are as follows: according to the plane hypothesis of the radial section, the tensile stress and the bending stress of the turbine blade at each node position of the radial section at the initial moment are obtained by adopting a beam theory and a numerical method; selecting a joint j point on a hypothetical plane, wherein the stress at the initial moment is sigmaj(0) At the lapse of 1 st period of time Δ1After t, assume that the j points are all subjected to σ in this periodj(0) Obtaining delta according to creep equation of material under action of stress1Creep strain increment at time t
Considering creep strain delta from the radial cross-sectional plane assumption
Obtaining j point total strain increment delta by adopting numerical method1εj(ii) a j point Δ1the stress increment at time t is:
wherein E isjThe modulus of elasticity at point j;
j point Δ1the stress at time t is:
σj(1)＝σj(0)+Δ1σj；
stress σ according to time i-1j(i-1) and creep equation of the material to obtain DeltaiCreep strain increment of j point corresponding to t time
Considering creep strain delta from the radial cross-sectional plane assumption
Obtaining j point total strain increment delta in a numerical modeiεj；
Δithe j point stress increment corresponding to t is:
wherein E isjThe modulus of elasticity at point j;
the stress at time j at time i is:
σj(i)＝σj(i-1)+Δiσj；
acquiring the equivalent stress of a j point in the action time of the external load; acquiring creep endurance strength reserve of a j point in the action time of the external load; acquiring creep endurance strength reserve of a j point under the combined action of a plurality of working conditions;
for the nodes corresponding to the k section and the k +1 section of two adjacent radial sections, the creep elongation is as follows:
wherein epsilonk+1Is the creep amount of the corresponding point of the k +1 section, epsilonkThe amount of creep of the corresponding point of the k section, hk+1Leaf height, h, of the corresponding point of the k +1 sectionkThe leaf height of a corresponding point of the k section;
the creep elongation for the overall leaf height was obtained as:
e. acquiring creep elongation and creep lasting damage of the blade;
the concrete implementation steps of the step e are as follows: and d, repeating the step d to obtain the calculation results of the stress, the strength reserve and the creep elongation of each node of all the radial sections, and obtaining the lasting damage of each node of the turbine blade in the working time according to the accumulated damage principle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611018355.9A CN106777479B (en) | 2016-11-18 | 2016-11-18 | Turbine blade nonlinear creep analysis method based on beam theory |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611018355.9A CN106777479B (en) | 2016-11-18 | 2016-11-18 | Turbine blade nonlinear creep analysis method based on beam theory |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106777479A CN106777479A (en) | 2017-05-31 |
| CN106777479B true CN106777479B (en) | 2020-04-21 |
Family
ID=58968298
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611018355.9A Active CN106777479B (en) | 2016-11-18 | 2016-11-18 | Turbine blade nonlinear creep analysis method based on beam theory |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106777479B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110245394B (en) * | 2019-05-28 | 2022-04-22 | 西北工业大学 | Creep equivalent and simplification method for close-packed air film hole of nickel-based single-crystal turbine cooling blade |
| CN112630045B (en) * | 2020-11-19 | 2024-04-12 | 西北工业大学 | Creep life prediction method of nickel-based single crystal alloy based on real blade sample |
| CN112945495B (en) * | 2021-02-05 | 2022-06-03 | 中国航发沈阳发动机研究所 | Method for testing fatigue strength of blades of aero-engine in batch |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104809273A (en) * | 2015-04-03 | 2015-07-29 | 北京航空航天大学 | Creep deformation describing method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9280620B2 (en) * | 2012-10-16 | 2016-03-08 | Siemens Aktiengesellschaft | Method and system for probabilistic fatigue crack life estimation |
-
2016
- 2016-11-18 CN CN201611018355.9A patent/CN106777479B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104809273A (en) * | 2015-04-03 | 2015-07-29 | 北京航空航天大学 | Creep deformation describing method |
Non-Patent Citations (3)
| Title |
|---|
| Creep Behaviors of Nickel-Based Single Crystal Superalloys Compact Tension Specimen at High Temperature;Zhixun Wen等;《Advances in Superalloys》;20101108;全文 * |
| 单晶涡轮叶片的蠕变计算分析;饶寿期等;《燃气涡轮试验与研究》;19981231;第11卷(第4期);第30-33页 * |
| 考虑应力松弛的单晶涡轮叶片蠕变疲劳寿命预测;高靖云等;《航空动力学报》;20160331;第31卷(第3期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106777479A (en) | 2017-05-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10527520B2 (en) | Operating wind motors and determining their remaining useful life | |
| CN106777479B (en) | Turbine blade nonlinear creep analysis method based on beam theory | |
| CN110175394A (en) | A kind of turbo blade spleen tissue extracts damage coupling Probabilistic Life Prediction calculation method | |
| WO2017163562A1 (en) | Remaining service life evaluating device and method, and wind power electricity generating system | |
| Hou et al. | Prediction of fatigue crack propagation lives of turbine discs with forging-induced initial cracks | |
| WO2019178974A1 (en) | Fatigue damage monitoring method for blade of wind-driven generator, and electronic device and storage medium | |
| Chatterjee et al. | Modal characteristics of turbine blade packets under lacing wire damage induced mistuning | |
| CN109855991B (en) | Method for predicting fatigue life of composite material | |
| KR20180014761A (en) | Scheduling of checks on machine components and prediction of end of life | |
| Heinze et al. | The impact of geometric scatter on high-cycle-fatigue of compressor blades | |
| JP2015052487A (en) | Material strength estimation device | |
| CN115758603A (en) | Method for predicting multi-working-condition creep/stress rupture life of turbine blade of aircraft engine | |
| CN111465837A (en) | Life evaluation device and life evaluation method | |
| CN108680431B (en) | Evaluation method for self-healing performance of cable sheath material | |
| Chen et al. | Stochastic modelling fatigue crack evolution and optimum maintenance strategy for composite blades of wind turbines | |
| CN112213090B (en) | Simplified spectrum compilation method for damage tolerance of helicopter maneuvering component | |
| CN114528743A (en) | Method for calculating dynamic stress monitoring limit value of rotor blade in wide rotating speed range | |
| Zhang et al. | Optimum maintenance strategy for fatigue damaged composite blades of offshore wind turbines using stochastic modelling | |
| He et al. | Stochastic modeling of damage physics for mechanical component prognostics using condition indicators | |
| Verma et al. | Optimal time scheduling for carrying out minor maintenance on a steam turbine | |
| Cathcart et al. | Probabilistic lifing methods for digital assets | |
| Kotambkar et al. | Modeling and investigation of modal properties under crack induced mistuning in a turbine blade packet | |
| Wilkie et al. | Ultimate limit state fragility of offshore wind turbines on monopile foundations | |
| Kotambkar et al. | Analytical and numerical investigation of lacing wire damage induced mistuning in turbine blade packet | |
| Schinas et al. | Assessment of extreme stresses and deflections on wind turbine blades with stochastic material properties using statistical extrapolation methods |
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 |