CN109446547A - A kind of strength calculation method of wind generating set pitch control cabinet mounting bracket - Google Patents
A kind of strength calculation method of wind generating set pitch control cabinet mounting bracket Download PDFInfo
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Abstract
The present invention relates to a kind of strength calculation methods of wind generating set pitch control cabinet mounting bracket, pass through Geometric Modeling, Dynamic Modeling and Dynamics Simulation Analysis, determine the two danger position operating conditions (i.e. extreme position operating condition) of variable pitch cabinet and its bracket during hub rotation, it is then based on extreme position operating condition, establish the finite element model including variable pitch cabinet and its bracket, apply gravitational load respectively, carry out the FEM calculation under two extreme position operating conditions, two finite Element Stress, the ultimate factor of safety and fatigue safety coefficient of variable pitch cabinet and its mounting bracket are calculated according to the two finite Element Stress.By the above method, the stress intensity for the mounting bracket that the present invention obtains and the accuracy of danger position operating condition are high, meet the actual loading situation of variable pitch cabinet and its bracket during hub rotation, can be realized the accurate check of variable pitch cabinet mounting bracket intensity.
Description
Technical field
The invention belongs to wind power plant performance detection technical fields, and in particular to a kind of wind generating set pitch control cabinet
The strength calculation method of mounting bracket.
Background technique
With the rapid development of social economy, demand of the people to the energy is also rapidly increasing.However it is limited to carbon emission
Etc. environmental factors and amount of storage increasingly consumption, the use of the fossil energy as non-renewable energy resources is by a certain extent
Limitation, so the renewable energy of the positive other cleanliness without any pollution of searching of people, to substitute traditional fossil energy.
The clean energy resourcies such as wind energy, solar energy, are increasingly valued by people, especially wind energy.Due to national policy
It supports energetically, the degree domestic of Wind turbines was gradually increased in recent years.In order to guarantee the reliability of Wind turbines equipment, need
The performances such as the fatigue strength to component each in blower are analyzed.
Pitch-controlled system plays an important role in MW grade wind driven generator unit structure and control system, variable pitch cabinet installation branch
Frame plays carrying and supporting role as the connection structure between variable pitch cabinet and wheel hub, to pitch-controlled system.If variable pitch cabinet is installed
Fatigue rupture occurs for bracket, can not only damage pitch-controlled system, influence wind-power electricity generation performance, or even can cause safety accident, therefore
In order to guarantee the normal operation of Wind turbines equipment, the intensity to variable pitch cabinet mounting bracket is needed to check.
Currently, most of scholar mainly concentrate wind power generating set inner hub, mainframe, rear frame, connection bolt and
The Intensity Design of the components such as tower carries out analytical calculation, counts without the intensity to wind generator variable-paddle cabinet mounting bracket
It calculates, it is thus impossible to estimate mounting bracket influence caused by entire generating set, not can guarantee the normal of Wind turbines equipment
Operation.
Summary of the invention
The object of the present invention is to provide a kind of strength calculation methods of wind generating set pitch control cabinet mounting bracket, for solving
Certainly the prior art leads to the reliable of Wind turbines equipment since the intensity not to generator variable pitch cabinet mounting bracket calculate
The low problem of property.
In order to solve the above technical problems, the present invention proposes a kind of Strength co-mputation of wind generating set pitch control cabinet mounting bracket
Method, comprising the following steps:
1) geometrical model of variable pitch cabinet and its mounting bracket is established, includes wheel hub, variable pitch cabinet and installation in the geometrical model
Bracket；
2) Dynamics Simulation Model of the geometrical model is established, obtains variable pitch cabinet and its mounting bracket in hub rotation mistake
Stress situation of change in journey, determine variable pitch cabinet and its mounting bracket during hub rotation one week stress maximum with it is the smallest
Two extreme position operating conditions；
3) grid dividing is carried out to the geometrical model, establishes the finite element mould under described two extreme position operating conditions respectively
Type；
4) gravitational load is applied to the finite element model under two extreme position operating conditions respectively, corresponding two poles are calculated
Under extreme position operating condition, two finite Element Stress of variable pitch cabinet and its mounting bracket weld seam hot spot during hub rotation one week,
The allowable stress of mounting bracket component is compared with each finite Element Stress, obtains the limiting safe of variable pitch cabinet mounting bracket
Coefficient.
The present invention passes through Geometric Modeling, Dynamic Modeling and Dynamics Simulation Analysis first, determines variable pitch cabinet and its installation
Two danger position operating conditions (i.e. extreme position operating condition) of bracket during hub rotation, are then based on extreme position operating condition,
The finite element model including variable pitch cabinet and its mounting bracket is established, applies gravitational load respectively, carries out two limiting conditions
Under FEM calculation, obtain under corresponding two extreme position operating conditions, variable pitch cabinet and its mounting bracket are in one week mistake of hub rotation
Two finite Element Stress of weld seam hot spot in journey, the finite Element Stress being calculated under a kind of extreme position operating condition is maximum, another
The finite Element Stress obtained under kind extreme position operating condition is minimum, by the allowable stress of mounting bracket component and each finite Element Stress
It is compared, finally obtains the ultimate factor of safety of two variable pitch cabinet mounting brackets, two ultimate factors of safety are all used for structure
Ultimate strength assessment think that the ultimate strength of structure meets GL specification when the wherein lesser ultimate factor of safety is greater than 1
Design requirement.By the above method, the stress intensity for the mounting bracket that the present invention obtains and the accuracy of danger position operating condition are high,
Meet the actual loading situation of variable pitch cabinet and its mounting bracket during hub rotation, it is strong to can be realized variable pitch cabinet mounting bracket
The accurate check of degree.
Finite Element Stress in order to obtain is determined by following steps:
Coordinate system is established according at the weld seam hot spot of mounting bracket, answering for weld seam hot spot is extracted based on the coordinate system respectively
Force component, according to the components of stress of weld seam hot spot calculate weld seam hot spot equivalent stress, using the equivalent stress of weld seam hot spot as
The finite Element Stress.The calculating formula of the equivalent stress of weld seam hot spot is as follows:
In formula, σeqvFor the equivalent stress of weld seam hot spot, σx、σy、τxyFor three stress point that weld seam hot spot is calculated
Amount.
To obtain the accurate components of stress of weld seam hot spot, further includes: according to the welding structure hotspot type of mounting bracket, adopt
Stress extrapolation is carried out with weld seam hot spot of the hot spot stress method to mounting bracket to calculate, and obtains the accurate stress point of the weld seam hot spot
Amount.
The stress situation of change of variable pitch cabinet and its mounting bracket during hub rotation in order to obtain, further includes: utilize
The heart applies angular velocity of rotation and acceleration of gravity around wheel hub axial direction, action edge credit of going forward side by side to Dynamics Simulation Model in the hub
Analysis obtains the stress situation of change of variable pitch cabinet and its mounting bracket during hub rotation.
In order to solve the above technical problems, the present invention also proposes a kind of intensitometer of wind generating set pitch control cabinet mounting bracket
Calculation method, further comprising the steps of:
1) geometrical model of variable pitch cabinet and its mounting bracket is established, includes wheel hub, variable pitch cabinet and installation in the geometrical model
Bracket；
2) Dynamics Simulation Model of the geometrical model is established, obtains variable pitch cabinet and its mounting bracket in hub rotation mistake
Stress situation of change in journey, determine variable pitch cabinet and its mounting bracket during hub rotation one week stress maximum with it is the smallest
Two extreme position operating conditions；
3) grid dividing is carried out to the geometrical model, establishes the finite element mould under described two extreme position operating conditions respectively
Type；
4) gravitational load is applied to the finite element model under two extreme position operating conditions respectively, corresponding two poles are calculated
Under extreme position operating condition, variable pitch cabinet and its mounting bracket move two finite Element Stress of weld seam hot spot in a circular flow in wheel hub,
In conjunction with critical plane algorithm, calculate separately to obtain the direct stress value of two weld seam hot spots；
5) according to wheel hub, the varied configurations fatigue load timing of fatigue load is composed in one week operational process, bond material
The direct stress value of two weld seam hot spots of S/N curve and weld seam hot spot, the fatigue damage and fatigue that mounting bracket is calculated are pacified
Overall coefficient.
The present invention determines variable pitch cabinet and its mounting bracket by Geometric Modeling, Dynamic Modeling and Dynamics Simulation Analysis
Two danger position operating conditions (i.e. extreme position operating condition) during hub rotation, are then based on extreme position operating condition, establish
Finite element model including variable pitch cabinet and its mounting bracket, applies gravitational load respectively, obtains two finite Element Stress and (divides
Dui Ying two extreme position operating conditions), in conjunction with critical plane algorithm, calculate separately to obtain the direct stress value of two weld seam hot spots,
The S/N curve and fatigue load timing of bond material are composed, and the fatigue safety coefficient of mounting bracket is calculated.The present invention being capable of mould
Intend the actual loading situation of true variable pitch cabinet and its mounting bracket in wind wheel rotation process, work can be operated normally in blower
The fatigue damage and fatigue safety coefficient of hub interior variable pitch cabinet mounting bracket are accurately and reliably obtained under condition.
The calculating formula of the direct stress value of above-mentioned weld seam hot spot is as follows:
In formula, σx(t, θ) is the direct stress value of weld seam hot spot under angle, θ, according to mounting bracket weld seam heat
Coordinate system is established at point, extracts three components of stress of weld seam hot spot respectively based on the coordinate system.
Obtain the accurate components of stress of weld seam hot spot, further includes: according to the welding structure hotspot type of mounting bracket, use
Hot spot stress method carries out stress extrapolation to the weld seam hot spot of mounting bracket and calculates, and obtains the accurate stress point of the weld seam hot spot
Amount.
Detailed description of the invention
Fig. 1 is the geometrical model schematic diagram in the embodiment of the present invention comprising wheel hub, variable pitch cabinet and its mounting bracket；
Fig. 2 is the kinetic model schematic diagram in the embodiment of the present invention comprising wheel hub, variable pitch cabinet and its mounting bracket；
Fig. 3 be in the embodiment of the present invention variable pitch cabinet and its bracket with stress variation diagram during hub rotation；
Fig. 4-a is variable pitch cabinet and its a kind of extreme position operating condition schematic diagram of mounting bracket in the embodiment of the present invention；
Fig. 4-b is variable pitch cabinet and its mounting bracket another kind extreme position operating condition schematic diagram in the embodiment of the present invention；
Fig. 5 is variable pitch cabinet and its bracket FEM model schematic diagram in the embodiment of the present invention；
Fig. 6 is the schematic diagram of welding toe structural stress of the invention；
Fig. 7 is the schematic diagram of welding structure hotspot type of the invention；
Fig. 8-1 is the schematic diagram of a type weld seam of the invention；
Fig. 8-2 is the schematic diagram of b type weld seam of the invention；
Fig. 9 is critical plane and stress schematic diagram of the invention；
Figure 10 is the S/N curve graph of variable pitch cabinet mounting bracket weld seam in the embodiment of the present invention；
Figure 11 is the strength calculation method flow chart of wind generating set pitch control cabinet mounting bracket of the invention；
The label declaration of the figures above is as follows: 1 is wheel hub, and 2 be variable pitch cabinet, and 3 be variable pitch cabinet mounting bracket, and 4 be elasticity branch
Support, 5 be wheel hub boss, and 6 be manhole, and 7 be variable pitch cabinet body center of gravity, and 8 be vertical plane；9 be variable pitch cabinet cabinet body, and 10 be variable pitch bottom of cabinet
Plate, 11 be variable pitch cabinet mounting bracket (calling mounting bracket in the following text).
Specific embodiment
A specific embodiment of the invention is further described with reference to the accompanying drawing.
A kind of strength calculation method of wind generating set pitch control cabinet mounting bracket of the invention, comprising the following steps:
1) geometrical model of wheel hub, variable pitch cabinet and its mounting bracket, the geometrical model such as Fig. 1 institute are established using three-dimensional software
Show, including wheel hub, variable pitch cabinet, mounting bracket and resilient support etc..
2) geometrical model of wheel hub, variable pitch cabinet and its mounting bracket is imported into dynamics analysis software Simpack, carried out whole
Each component is arranged as shown in Fig. 2, carrying out Model Mounting according to component physical location in the multi-body dynamics modeling of a assembly
Attribute and connection relationship establish Dynamics Simulation Model, in the hub the heart apply wheel hub operate normally when angular velocity of rotation and
Acceleration of gravity carries out dynamic analysis, obtains variable pitch cabinet and its mounting bracket stress variation maximum and the smallest two danger
Position (i.e. extreme position operating condition), the calculating for subsequent finite element model.Detailed process is as follows:
During Dynamic Modeling, wheel hub, variable pitch cabinet and its mounting bracket are modeled using rigid body, between component
It is connected using fixed hinge, and hub centre and ground are applied in rotation hinged place around hub axis using rotation articulated connection
The angular velocity of rotation in direction, and apply acceleration of gravity, consider gravity to the setting time of integration of variable pitch cabinet and its mounting bracket,
The dynamics simulation for carrying out overall model, to obtain the constraint reaction of variable pitch cabinet mounting bracket hinged place with hub rotation
Situation of change in the process, the stress versus time curve of variable pitch cabinet and its mounting bracket during hub rotation is as schemed
Shown in 3, variable pitch cabinet and its mounting bracket stress maximum and the smallest two turned positions during hub rotation are thereby determined that,
I.e. variable pitch cabinet and mounting bracket level are upward with horizontal two danger positions downward, two limit as subsequent finite element analysis
Position operating condition.
3) it is symmetric due to three variable pitch cabinets in hub interior, therefore to simplify finite element analysis, become with one of
Paddle cabinet and its mounting bracket are research object, analyze its strength character.Variable pitch cabinet and its geometrical model of mounting bracket are imported
Grid dividing software hypermesh carries out grid dividing to variable pitch cabinet and mounting bracket, and the attribute of set parts with connect pass
Finite element model, according to two determining extreme position operating conditions, is separately adjusted to angularly the corresponding positions of two extreme position operating conditions by system
It sets, as shown in Fig. 4-a, Fig. 4-b.
When variable pitch cabinet and its mounting bracket are in two kinds of otherwise limit operating conditions, location in the hub is different, by
It is influenced in gravity, cabinet body and the practical contact condition of mounting bracket are also different, therefore the two is arranged according to practical contact condition
Between contact area.One of extreme position operating condition is variable pitch cabinet level placement status upward, as depicted in fig. 4-a, cabinet at this time
Body weight is undertaken by the entire contact surface of mounting bracket, so when using between cabinet body and the load-carrying surface of mounting bracket use face face tie up
It is fixed to connect；Another extreme position operating condition is placement status under variable pitch cabinet horizontal direction, as shown in Fig. 4-b, at this time cabinet body with
Mounting bracket is only bolted by connection, therefore is only connected in bolt hole area using the binding of face face.
The finite element model under two kinds of extreme position operating conditions is established, detailed process is as follows:
In finite element modeling, variable pitch cabinet body and its bottom plate use hexahedral element grid division, and mounting bracket uses four
Face body unit grid division is connected by the binding of face face between cabinet body and bottom plate and between bottom plate and mounting bracket,
It is bolted with simulation；Variable pitch cabinet material is disposed as SUS304 stainless steel, and mounting bracket material is set as Q235 structural steel.
Variable pitch cabinet and the solid element size of mesh opening of mounting bracket are disposed as 2-30mm；Variable pitch cabinet is drawn using Low-Order Elements in FEM
Subnetting lattice, and 1 layer of grid is arranged in plate thickness direction；Cabinet body bottom plate uses Element of High Order grid division, and 3 layers of net are arranged in plate thickness direction
Lattice；Mounting bracket uses high-order tetrahedron element grid division, as shown in Figure 5.
In variable pitch cabinet and the finite element model of mounting bracket, the specific setting of each component is as shown in table 1；
Table 1
4) grid model under two kinds of extreme position operating conditions is imported in finite element analysis software ANSYS, variable pitch cabinet is set
And its connection relationship, load transferring mode and boundary condition between mounting bracket.
Consider that the gravity of interior of the cabinet component influences, establish quality point in the position of centre of gravity of variable pitch cabinet, and by the point with
Cabinet body bottom plate is bound the way of contact by point face and is connected；One is established respectively at four resilient support hole centers of mounting bracket
It is connected, constrains four quality points by quality point with corresponding bottom welding plate surface using point face binding
The degree of freedom on a node basis, to simulate the resilient support constraint between mounting bracket and wheel hub at four mounting holes.
5) coordinate system of finite element model is parallel with the tower top coordinate system in GL2010 specification, i.e., X-axis is by blower upwind
It is directed toward lower wind direction, Y-axis is horizontally directed to, and Z axis is straight up.To global finite element model apply acceleration of gravity, i.e., Z axis just
Direction applies acceleration of gravity, carries out to variable pitch cabinet and its mounting bracket finite element model limited under two extreme position operating conditions
Member calculates, and obtains under corresponding two extreme position operating conditions, and variable pitch cabinet and its mounting bracket move weld seam in a circular flow in wheel hub
Two finite Element Stress of hot spot, establish coordinate system according at the weld seam hot spot of mounting bracket, the direction regulation of the coordinate system
As follows: X-direction is along bead direction, and Y direction is perpendicular to bead direction, and Z-direction and X-axis, Y-axis are at right-hand rule right angle
Coordinate system.Extract the components of stress of weld seam hot spot, including 3 direct stress component σ respectively based on the coordinate systemx、σy、σzIt is cut with 3
Shearing stress component τxy、τyz、τxz, three components of stress σ of present invention extractionx、σy、τxy, i.e. σxTo be parallel to just answering for bead direction
Power, σyFor the direct stress perpendicular to bead direction, τxyFor the shear stress in X/Y plane.According to the components of stress of weld seam hot spot
σx、σy、τxyThe equivalent stress for calculating weld seam hot spot, by the equivalent stress of the allowable stress of mounting bracket component and weld seam hot spot into
Row compares, and obtains the ultimate factor of safety of variable pitch cabinet mounting bracket.
The calculating formula of the equivalent stress of above-mentioned weld seam hot spot is as follows:
It is the equivalent stress of weld seam hot spot, σ in formulax、σy、τxyFor three components of stress that weld seam hot spot is calculated.
Specifically, using the ratio of the equivalent stress of component allowable stress and weld seam hot spot as the pole of variable pitch cabinet mounting bracket
Safety coefficient is limited, when the ultimate factor of safety is compared with 1, mounting bracket weld seam ultimate strength, i.e. limiting safe are assessed with this
When coefficient is greater than 1, judgement meets design requirement.
If in the calculating process that material factor is considered to the ultimate factor of safety, then, the meter of the ultimate factor of safety
Formula is as follows:
Wherein, SRF1(Stress reserve fator) indicates to consider the ultimate factor of safety of material factor,
σallowableIndicate allowable stress, σoccurringExpression obtains the equivalent stress of weld seam hot spot, i.e. σeqv, γmIndicate that material is safely
Number takes 1.1 according to GL2010 specification.
Since mounting bracket is welded by steel plate, danger position usually occurs in gusset and mounting bracket welding position
It sets, since position while welding is there are singular stress, this is caused to be in the weld seam heat for carrying out FEM calculation extraction in finite element model
Point the components of stress inaccuracy, for improve the components of stress accuracy, according to the welding structure hot spot class of variable pitch cabinet mounting bracket
Type carries out outside stress the weld seam hot spot of variable pitch cabinet mounting bracket using the hot spot stress method of International Welding association (IIW) specification
Calculating is pushed away, obtains the accurate components of stress of weld seam hot spot (including " stress of welding toe " obtained using " a type weld seam extrapolation "
" stress of welding toe " obtained with " b type weld seam extrapolation ").
6) two finite Element Stress of above-mentioned weld seam hot spot calculate separately to obtain two weld seams in conjunction with critical plane algorithm
The direct stress value of hot spot；According to the variation of wheel hub fatigue load in one week operational process, mounting bracket is obtained in hub rotation mistake
Stress condition in journey, and based on stress condition construction fatigue load timing spectrum；According to being calculated two of weld seam hot spot
The direct stress value of weld seam hot spot, in conjunction with fatigue load timing spectrum and the S/N curve of weld seam, using analysis of fatigue software Fesafe,
The Calculation of Fatigue Strength for carrying out weld seam hot spot, obtains the fatigue damage and fatigue safety coefficient of mounting bracket.
The present invention is as follows using the meaning that hot spot stress method carries out stress extrapolation calculating:
Welding toe total stress includes that geometry stress and the concentration of the stress as caused by local notch (i.e. toe of weld) are (non-linear
Peak stress).Since toe of weld position is singular stress point, the concentration of the stress due to caused by local notch (i.e. toe of weld) need to be excluded.
The definition of hot spot stress method is that, based on the stress perpendicular to two reference points on weld seam path, extrapolation calculates in IIW specification
To the structural stress (the i.e. accurate components of stress) of welding toe, as shown in Figure 6.
Welding structure hotspot type has two classes, respectively a type hot spot and b type hot spot, as shown in Figure 7, wherein a type hot spot
Toe of weld be located at welding plate surface, the toe of weld of b type hot spot is located at the edge of welded plate.It is standardized, is chosen perpendicular to weld seam according to IIW
Direction be interpolation path, different types of hot spot has different reference point and extrapolation calculation formula, a type weld seam and the weldering of b type
The reference point locations being considered as when seam stress extrapolation are respectively as shown in Fig. 8-1 and Fig. 8-2.
For a type weld seam, the node on interpolation path at selected distance toe of weld 0.4t and 1t is as a reference point, into
The extrapolation of row two o'clock stress, stress extrapolation calculation formula are as follows:
σhs=1.67 × σ0.4-0.67×σ1t (2)
In formula, σhsFor stress (the i.e. accurate components of stress of weld seam hot spot, when welding structure hotspot type is a of welding toe
When type weld seam, σx、σy、τxyTo be calculated by above-mentioned stress extrapolation calculation formula)；σ0.4For on interpolation path away from toe of weld
The stress of 0.4t；σ1tFor the stress away from toe of weld 1t on interpolation path.
For b type weld seam, it is located at the edge of plate, welding toe stress is independent of plate thickness, therefore the choosing of reference point
It takes without considering that plate thickness, b type weld seam generally use 3 stress extrapolations, stress extrapolation calculation formula is as follows:
σhs=3 × σ4mm-3×σ8mm+σ12mm (3)
In formula, σhsFor stress (the i.e. accurate components of stress of weld seam hot spot, when welding structure hotspot type is b of welding toe
When type weld seam, σx、σy、τxyTo be calculated by above-mentioned stress extrapolation calculation formula), σ4mmFor on interpolation path away from toe of weld
The stress of 4mm；σ8mmFor the stress away from toe of weld 8mm on interpolation path；σ12mmFor the stress away from toe of weld 12mm on interpolation path.
Since fatigue fracture typically occurs in body structure surface, and surface stress is two dimensional stress state, therefore according to IIW
Hot spot stress method in specification carries out stress extrapolation calculation formula and obtains the accurate components of stress of mounting bracket surface weld hot spot,
The i.e. three accurate components of stress (σ x, σ y, τ xy) then use the following equation gauging surface weld seam hot spot of critical plane algorithm
Direct stress value under different directions (also referred to as angle):
In above formula, σx(t, θ) is maximum (normal) stress value of the surface weld hot spot under different directions (also referred to as angle, θ),
Normal stress under i.e. each critical plane；σx(t,0)、σy(t,0)、τxy(t, 0) carries out stress extrapolation calculation formula and obtains
Three accurate components of stress, t indicate extreme position operating condition, and stress maximum extreme position operating condition is indicated when t=1, and t=2 is indicated
The smallest extreme position operating condition of stress, θ usually take every 10 ° a numerical value (being usually divided into 18 planes), i.e., θ=0 °,
10 °, 20 °, 30 ° ... 170 °, 180 °, have thus obtained the maximum (normal) stress value under all directions, then each with these
Stress value under direction carries out fatigue mechanisms respectively, and carries out fatigue analysis, therefore, this point of difference using these results
The method that direction (also referred to as angle) carries out fatigue mechanisms is known as critical plane algorithm, and " each critical plane " that the present invention mentions refers to
Be direction under all angles, the vivid plan-position for being known as being constructed under the angle, as shown in Figure 9.
The specific method is as follows for the fatigue damage and fatigue safety coefficient of mounting bracket of the present invention:
Firstly, in conjunction with result of finite element and weld seam hot spot stress extrapolation formula (2) under two extreme position operating conditions,
The accurate components of stress (the σ of weld seam hot spot is calculatedx、σy、τxy), then obtained according to the calculation formula (4) of critical plane algorithm
Maximum (normal) stress value of the weld seam hot spot under a certain angle under to two extreme position operating conditions, finally by two maximum (normal) stress values
It is composed with fatigue load timing and imports analysis of fatigue software Fesafe, and definition material S/N curve, using the rain-flow counting in software
Method obtains the fatigue damage and fatigue safety coefficient of weld seam hot spot.
Rain-flow counting rule is a kind of by irregular, random load history (random load spectrum), is converted into one
The cycle counting method of the variable amplitude loading spectrum of series of cycles, the purpose of this method are the circulations time provided under certain perseverance width stress S effect
Number n calculates fatigue damage value D=n/N in conjunction with the N that S/N curve gives.
By taking the Fatigue Damage Calculation under 0 degree of plane as an example: the maximum (normal) stress being calculated of extrapolating under two kinds of limiting conditions
Value is respectively σ1=10MPa, σ2=-10MPa, then the range of stress is △ σi=σ1-σ2=20MPa.It is answered at material S/N knee of curve
Power range (has contemplated that material factor γmIt=1.25) is △ σD=46.78MPa is determined according to wind speed round, that is, operating condition design
It is n that fatigue load, which acts on cycle-index,i=9.88 × 107.Fatigue load cycle-index allowable is calculated according to formula are as follows:
Cycle-index is acted on further according to fatigue load and following fatigue damage is calculated in fatigue load cycle-index allowable
With fatigue safety coefficient:
Wherein, D is fatigue damage, and the definition of fatigue damage is fatigue load effect cycle-index niWith cycle-index allowable
NiThe ratio between, and cycle-index N allowableiIt is to be calculated by the S/N curve of material, SRF2For fatigue safety coefficient.GL2010
Regulation, it is finger fatigue damage less than 1 that component fatigue strength, which is met the requirements, i.e. when fatigue safety coefficient SRF is greater than 1, as
Meet design requirement.
The S/N curve of mounting bracket weld seam of the present invention is to standardize determination according to GL2010, and as shown in Figure 10, wherein S is
The range of stress, N are stress-number of cycles, i.e., S-N curve is given under range of stress S effect, and the service life for being recycled to destruction is N.
If real load cycle-index is ni, then according to Miner defect theory, the damage of component may be defined as D=ni/N.Fatigue load
Timing spectrum is that the situation of change of the gravity according to suffered by variable pitch cabinet at hub rotation one week determines that fatigue load acts on cycle-index
It is then the revolving speed determination according to Wind turbines during 20 year service life.
In conclusion the strength calculation method of variable pitch cabinet bracket of the present invention is as shown in figure 11, first by establishing variable pitch cabinet
And its geometrical model of mounting bracket carries out Dynamic Modeling and Dynamics Simulation Analysis, determines that variable pitch cabinet and its mounting bracket exist
Two danger position operating conditions (i.e. extreme position operating condition) during hub rotation, are then based on the extreme position operating condition, establish
Finite element model including variable pitch cabinet and its mounting bracket, applies gravitational load respectively, carries out under two limiting conditions
FEM calculation carries out stress extrapolation with hot spot stress method to weld seam hot spot in conjunction with IIW specification and calculates, obtains weld seam hot spot
The accurate components of stress (σx、σy、τxy), according to the accurate components of stress calculate equivalent stress, and with the allowable stress of component ratio
Compared with the ultimate strength of check mounting bracket weld seam；Further according to the accurate components of stress and critical plane method of weld seam hot spot, calculate
The direct stress value of two weld seam hot spots is obtained, in conjunction with fatigue load timing spectrum and the S/N curve of material, using Fesafe software,
Check the fatigue damage and fatigue safety coefficient of mounting bracket weld seam.By the above method, the present invention can simulate true change
The actual loading situation of paddle cabinet and its mounting bracket in wind wheel rotation process, the stress intensity of obtained mounting bracket and danger
Position accuracy is high, meets the actual loading situation of variable pitch cabinet and its mounting bracket during hub rotation, can be in blower
The maximum stress and minimum stress of hub interior variable pitch cabinet mounting bracket, Jin Erneng are accurately and reliably checked under accidental conditions
Enough realize the accurate check of variable pitch cabinet mounting bracket intensity.
The above description is only a preferred embodiment of the present invention, is not intended to restrict the invention, for those skilled in the art
For member, the invention may be variously modified and varied.All within the spirits and principles of the present invention, it is made it is any modification,
Equivalent replacement, improvement etc., should be included within scope of the presently claimed invention.
Claims (8)
1. a kind of strength calculation method of wind generating set pitch control cabinet mounting bracket, which comprises the following steps:
1) geometrical model of variable pitch cabinet and its mounting bracket is established, includes wheel hub, variable pitch cabinet and mounting bracket in the geometrical model；
2) Dynamics Simulation Model of the geometrical model is established, obtains variable pitch cabinet and its mounting bracket during hub rotation
Stress situation of change, determine variable pitch cabinet and its bracket stress maximum and the smallest two limit during hub rotation one week
Position operating condition；
3) grid dividing is carried out to the geometrical model, establishes the finite element model under described two extreme position operating conditions respectively；
4) gravitational load is applied to the finite element model under two extreme position operating conditions respectively, corresponding two limit positions are calculated
It sets under operating condition, two finite Element Stress of variable pitch cabinet and its mounting bracket weld seam hot spot during hub rotation one week will pacify
The allowable stress of dress bracket component is compared with each finite Element Stress, obtains the limiting safe system of variable pitch cabinet mounting bracket
Number.
2. the strength calculation method of wind generating set pitch control cabinet mounting bracket according to claim 1, which is characterized in that
The finite Element Stress is determined by following steps:
Coordinate system is established according at the weld seam hot spot of mounting bracket, extracts the stress point of weld seam hot spot respectively based on the coordinate system
Amount calculates the equivalent stress of weld seam hot spot according to the components of stress of weld seam hot spot, using the equivalent stress of weld seam hot spot as described in
Finite Element Stress.
3. the strength calculation method of wind generating set pitch control cabinet mounting bracket according to claim 2, which is characterized in that
Further include: according to the welding structure hotspot type of mounting bracket, carried out using weld seam hot spot of the hot spot stress method to mounting bracket
Stress extrapolation calculates, and obtains the accurate components of stress of the weld seam hot spot.
4. the strength calculation method of wind generating set pitch control cabinet mounting bracket according to claim 3, which is characterized in that
The calculating formula of the equivalent stress of weld seam hot spot is as follows:
In formula, σeqvFor the equivalent stress of weld seam hot spot, σx、σy、τxyFor three components of stress that weld seam hot spot is calculated.
5. the strength calculation method of wind generating set pitch control cabinet mounting bracket according to claim 1, which is characterized in that
Stress situation of change of the variable pitch cabinet and its mounting bracket of step 2) during hub rotation is to utilize Dynamics Simulation Model
The heart applies the angular velocity of rotation and acceleration of gravity around wheel hub axial direction in the hub, goes forward side by side and takes action what mechanical analysis obtained.
6. a kind of strength calculation method of wind generating set pitch control cabinet mounting bracket, which comprises the following steps:
1) geometrical model of variable pitch cabinet and its mounting bracket is established, includes wheel hub, variable pitch cabinet and mounting bracket in the geometrical model；
2) Dynamics Simulation Model of the geometrical model is established, obtains variable pitch cabinet and its mounting bracket during hub rotation
Stress situation of change, determine variable pitch cabinet and its mounting bracket the stress maximum and two the smallest during hub rotation one week
Extreme position operating condition；
3) grid dividing is carried out to the geometrical model, establishes the finite element model under described two extreme position operating conditions respectively；
4) gravitational load is applied to the finite element model under two extreme position operating conditions respectively, corresponding two limit positions are calculated
It sets under operating condition, variable pitch cabinet and its mounting bracket move two finite Element Stress of weld seam hot spot in a circular flow in wheel hub, in conjunction with
Critical plane algorithm calculates separately to obtain the direct stress value of two weld seam hot spots；
5) according to wheel hub, the varied configurations fatigue load timing of fatigue load is composed in one week operational process, the S/N of bond material
Fatigue damage and the fatigue safety system of mounting bracket is calculated in the direct stress value of two weld seam hot spots of curve and weld seam hot spot
Number.
7. the strength calculation method of wind generating set pitch control cabinet mounting bracket according to claim 6, which is characterized in that
The calculating formula of the direct stress value of weld seam hot spot is as follows:
In formula, σx(t, θ) is the direct stress value of weld seam hot spot under angle, θ, according to built at the weld seam hot spot of mounting bracket
Vertical coordinate system, three components of stress for extracting weld seam hot spot respectively based on the coordinate system.
8. the strength calculation method of wind generating set pitch control cabinet mounting bracket according to claim 7, which is characterized in that
Further include: according to the welding structure hotspot type of mounting bracket, carried out using weld seam hot spot of the hot spot stress method to mounting bracket
Stress extrapolation calculates, and obtains the accurate components of stress of the weld seam hot spot.
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| CN113468712A (en) * | 2020-03-30 | 2021-10-01 | 新疆金风科技股份有限公司 | Method and device for determining service life of structural stress component of wind turbine generator |
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| CN113468712B (en) * | 2020-03-30 | 2024-01-30 | 金风科技股份有限公司 | Method and equipment for determining service life of stressed component of wind turbine generator structure |
| CN112668124A (en) * | 2021-01-04 | 2021-04-16 | 上海电气风电集团股份有限公司 | Method and device for determining limit design load of wind generating set and computer readable storage medium |
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