Wind Energy,

Engineering Services and Software Solutions for System

Level Simulation from among Wind Turbine Simulation

이혁재 과장MSC Korea 2009

Agenda

• Engineering Challenges for Wind Turbine Manufacturers

• Simulation of Wind Turbine using MBS

• Reference

7/30/2009 2

Trends

• Increase of power generated per WT

• Result: Growing size

Engineering challenges

• Reliability vs. reduction of “Top Head” mass

E.g. relative gear box weight down, failure rates up

Growing size increasing structural elasticity/flexibility

• Acoustic performance (noise reduction)

• Maximum efficiency and aerodynamic performance

Also at low wind speeds

• Offshore expansion

Wind Turbine Trends & Engineering Challenges

3

0

20

40

60

80

100

120

140

160

1980 1985 1990 1995 2000 2005 20101980 1985 1990 1995 2000 2005 2010

50kW 300kW

500kW600kW

1.5MW

2.5MW

6.5MW

10MW?

160

140

120

100

80

60

40

20

0

Ro

tor

Dia

mete

r

• Limitations of physical tests

Size of equipment (rotor blades, tower, …) limits number of available test facilities

Control over loads

(weather / wind conditions)

Expensive, slow, late

in development cycle

Limited understanding of durability

issues

• Simulation advantages

Accelerate time to market

Allows prediction of durability issues

Increasing system reliability

Decreasing warranty and maintenance

expenses

Virtual tests against various weather

(wind, off-shore: waves) conditions

System size not an issue

Value of Simulation

4

Process for Design Evaluation

5

Type Certification according to IEC WT01

Design Evaluation

Safety System

Rotor Blades

Electrical Components

Personal Safety

Nacelle / Spinner

Loads

Mechanical

Components

Tower

Foundation &

Bases

Manuals (maintenance,

manufacturing, commissioning)

Process for Design Evaluation

6

Process for Design Evaluation

7

Process for Design Evaluation (Cont.)

8

IEC/Specified

StandardAerodynamic

Detail Design

1. Dynamic

2. Composite

3. Fluid

…Control

1. C, Fotran etc

2. Simulink or Easy 5Fatigue

Analysis

Load Calculation

Extreme/Fatigue

Load Extract

System Modeling

(Parameterized)

Force & Moment

Vibration

Extreme Load

Fatigue Load

FE Analysis

System Simulation

Structure Simulation

Simulation of Wind Turbine using MBS

7/30/2009

• Adams is a very flexible software for general mechanical system simulation

• Applied on wind turbines, detailed models can be created including gear

boxes, control systems, bearings, etc

• Adams has been used for wind turbine simulations for more than 10 years

• Static analysis, dynamic analysis and frequency domain analysis

Complete Wind Turbine Simulation

Aerodynamics

Control systems

Hydraulics

Electric systems

Flexible bodies

Roller bearings

Gears

Linearization

Frequency

domain analysis

Transient analysis

System performance

Load histories

Disp / Vel / Acc

Stress recovery

10

Gear Modeling ; Subsystem Level

• Idealized constraints

The most simple approach

Add gear ratio between axles

No back lash

• Simplified gear contact

Analytical contact calculation, based on true gear

geometry

Very fast to simulate

Spur gears, helical gears, bevel gears, planetary gears

Takes back lash into account

Load investigation of shafts and bearings

Study of gear rattle and general system behavior due to

lash and losses in gears

Incre

ased

accura

cy

11

Gear Modeling (Cont.) ; Subsystem Level

• Detailed 3D contact

Generates accurate gear geometry in Adams

3D contact between rigid gears

Load investigation of gears, shafts and

bearings

Study of gear rattle and general system

behavior due to lash and losses in gears

Friction in tooth contact

Incre

ased

accura

cy

• Flexible gear contact

Uses Nastran as pre-processor to generate accurate data for

flexible tooth contact in Adams

High level of detail, takes local tooth flexibility into account

12

Geartrain System Simulation ; Subsystem Level

Options in MD Adams

• Kinematic coupling

• GearTrain toolkit*

• User defined subroutines

13

Business: Manual transmissions, transaxles, driveline products

Challenge: Eliminate gear noise problems

Solution: Using Adams to investigate rattle generation in early stages of design, before any hardware is built

Value: Simulation saves tens of $K and months of development effort, and improves designs

“Predictive engineering is key to optimizing designs early in the development cycle. We can test and fix designs in the computer so we get it right before any parts are built.”

-- Bob Perkins Manager of Engineering Systems

Case Study – New Venture Gear

14

Bearing Modeling ; Subsystem Level

• Linear six component spring-damper

• Non-linear six-component force

• Detailed ball/roller bearing model

Takes local flexibility into account

Outer ring is rigid, doesn’t take gearbox flexibility into account

Nastran is used as preprocessor to generate bearing data for Adams

Picture below shows ball bearing but roller bearing is also available

Incre

ased

accura

cy

15

Bearing Modeling ; Subsystem Level

MD Nastran

• Statics

• Dynamics

• 2D / 3D Contacts

• Thermal

• Common data model

Department interoperability

Cost and time savings

• Combined nonlinearity

Geometric & material

• Glueing

• Friction

Incl. heat generation

7/30/2009 16

MD Adams

• Kinematic coupling

• Compliances

Linear

Nonlinear

User-defined subroutines

• Rolling bearing toolkit*

Automated design process

Contact force model

Finest FE-meshes

Fast contact simulation

Fast system simulation

• Flexible bearing contact

Bearing Modeling, continued ; Subsystem Level

17

Brake Systems ; Subsystem Level

• Rigid disc

Model as torque applied to shaft

User defines brake torque magnitude based on any state in the model,

for example angular velocity of shaft, pitch angles, etc

Can also include PID controller

• Flexible disc

High fidelity model, can be used for analysis of brake squeal and other

vibration-related problems

• Import Control System from Control Design Code (Easy5 or MATLAB/Simulink)

Detailed models can be imported into Adams and connected to the

mechanical model

Preserves investments already made in Control Design Code

Typical approach is to import control system from Control Design Code

that sets a torque in the Adams model

18

Case Study:

Bosch Brake Systems

Business: Second largest supplier of automotive technology worldwide

Challenge:Assess the influence of design parameters on the brake assembly’s dynamic response, including thermal effects

Solution:Modal force element in Adams, which captures the thermal deformation calculated with MSC.NASTRAN.

Value: Reduced the need for physical prototypes through increased accuracy of virtual approach

“Thermal deformations can readily be included through modal force definitions which lead to an accurate component response. A significant system influences can be noted”

-- Richard A. Swift, Ph.D, BOSCH Automotive Corporation

19

2009-07-30 20

ADAMS WindTurbine Toolkit ; System Level

• ADAMS WindTurbine Toolkit has been developed under contract to the National Renewable Energy Laboratory (NREL) specifically for modeling horizontal-axis wind turbines

• ADAMS WindTurbine Toolkit can be thought of as an “overlay” for ADAMS/View

• ADAMS WindTurbine Toolkit gives the user greater confidence in his model’s fidelity by automating the turbine modeling process

• This tool is used for:

Calculating loads for fatigue analysis

Estimate torques in power train

Verifying system dynamics

Etc

• There are 2 different types of ADAMS WindTurbine Toolkit:

ADAMS/WT 2.0

ADAMS/Adwimo

Flexible blades

Flexible tower

Aerodynamic forces

applied on blades

Power train

with generator

• Flexible rotor blades

• Flexible tower, can be supported by wires

• Aerodynamic forces on blades

• Detailed aerodynamic model, includes turbulence, wind shear and tower shadow

• Rather simple power train model

• Rigid hub with flexible connection to blades

Common modeling• Aerodynamic forces act at a point

• Smooth load distribution by nastran

• NREL / Aerodyn

• Certified by Germanischer Lloyd

• ADAMS open SW-architecture

• User subroutines (C,FORTRAN)

• Large number of utilities

Adv. aerodynamic modeling• Distributed aerodyn. pressure

• On-going research

Blade modelling - Aerodynamics

2009-07-30 21

22

ADAMS/WT 2.0 Toolkit ; System Level

• ADAMS/WT 2.0 can select,

the direction of rotor rotation and whether

the rotor is an upwind or downwind config.

• Straight, tapered flexible beam

Untwisted version of flexible rotor blade element

Optionally, add sets of guy wires

• Input for tower:

Mass/unit length, Section mass moments of inertia, Section CG offsets from reference axis

Structural twist, Torsional stiffness, Lateral stiffness, Extensional stiffness

2009-07-30 22

FIELD

element

Part

boundary

2009-07-30 23

• Straight, rigid blade plus flapping hinge (Including Lumped masses, beams elements)

• Input for rotor blades:

Mass/unit length, Section mass moments of inertia, Section CG offsets from reference axis

Structural twist, Torsional stiffness, Lateral stiffness, Extensional stiffness

• Aerodynamic forces on blades

Simple model

CL = dCL/da * a

CD = CD0

Advanced model

AeroDyn routine, developed by University of Utah

Takes into account turbulence, wind shear, tower shadow

ADAMS/WT 2.0 Toolkit ; System Level

Hinge

2009-07-30 24

• Four types of rigid rotor hubs, with flexible connections to blades

Hub flexibility

It’s add flexible BUSHING elements between the dummy PARTs at the blade

attachment markers and the hub itself

ADAMS/WT 2.0 Toolkit ; System Level

2009-07-30 25

Aero dynamic loads

• AeroDyn fully integrated with Adams

AeroDyn is an aerodynamics software library for use by designers of horizontal-axis

wind turbines

The aerodynamics model in AeroDyn is a detailed analysis that includes blade-

element/momentum theory (with modifications to improve accuracy in yawed flow),

dynamic stall, and an optional dynamic inflow theory

Includes full-field turbulence wind model

AeroDyn is maintained by National Renewable Energy Laboratory (NREL) in the US

• Adams’ open architecture allows other codes to be added

2009-07-30 26

• Rather simple power train model

• Idealized gearbox with gear ratio

• Flexible shafts (rotational stiffness only)

• Induction-Type Motor-Generator

Thevenin’s Equation or Functional Definition

ADAMS/WT 2.0 Toolkit ; System Level

Modeling

• Easier-to-use

• Parametrics

• Aerodynamics

NREL/AERODYN

User-defined

Simulation

• Batch

ADAMS/WT 2.0 Toolkit Simulation ; System Level

27

Control systems

• Simple controllers (PID) can be created directly in Adams

• For more advanced controllers, MATLAB/Simulink and Easy5 models can be

imported into Adams

• Adams solves the fully coupled control+mechanical system

• Typical applications are pitch control, yaw control, brake system, pitch control

hydraulics, etcAdams

Simulink

Easy5

28

Case Study

MOOG JAPAN LTD

Business:General Machine, Wind Turbines

Challenge:Introduction of Servo actuator simulation by

using Easy5

Solution:A simulation example of the pitch control servo

actuator for wind-power generation system was performed using Easy5

Value:Simulation was performed with a typical hydraulic circuit and differential hydraulic circuit. The cause of the difference with simulation is being studied.

Case Study

Servo Valve(var area gradient)

Upstream BoundaryConditions (P, T)

P = 250

T = 50

Global FluidProperties

HydraulicFluid

8

2 Chamber Actuatorw position input

Split S->RS Fixed orifice

Single Mass(hard limits & friction)

-1

1

SaturationFunction

-100

100Gain=1

100

Gain Block

Constant pressure source

I_SV

Check ValveS->R (P)

Check ValveS->R (P)

IDIFF

Two tabularfunctions of time

REF

POS

Merge SSS->R

Merge SSS->R

Check ValveS->R (P)

Split w/orifices S->RR (P)

Check ValveS->R (P)

Merge SSS->R

CV_PILOT_PCV_PILOT_P

Check ValveS->R (P)

Check ValveS->R (P)

Split w/orifices S->RR (P)

CV_PILOT_PCV_PILOT_P

Fixed orifice

Adiabatic AccumulatorGas-charged

AdiabaticVolume (P)

wind_ACTR(6)

29

• To assemble a full parametrik windturbine you need the mnf files and some informations(initial setup, information about node ids)

conceptual design

• You can start a simulation without aerodyn forces, there is a initial velocity on the hub

• Running the simulation (with Multi Analyse)

ADAMS/Adwimo Toolkit Modeling Steps ; System Level

FREC. : 0.45 Hz

DAMPING : 0.36%

FREC. : 5.04 Hz

DAMPING : 1.6%FREC. : 44 Hz

DAMPING : 1.03%

ADAMS/Adwimo Toolkit Modeling Steps ; System Level

• Change the parameters to

get a new design,

such as tilt angle, cone angle,

overhang, initial pitch angle….

• Add a gearbox from a predefined library,

or add your own to the library

• Complete your windturbine

with aeroforces time dependent forces

and aerodyn (dev. by NREL) forces are

embedded and finish your setup

with the definition of a controller

ADAMS/Adwimo Toolkit Modeling Steps ; System Level

• Simulate your windturbine, either in a single interactive mode, or in a batch mode with different wind input file, or use the full power of Adams/View and Adams/Insight to study the design

• Import your existing FAST (dev by NREL) model,

and update the model with flexible in one step

ADAMS/Adwimo Toolkit with Flexible body simulation

• Discrete flexibility (ADAMS/WT 2.0)

Masses connected with beam elements

Will capture stiffening effects due to

rotation, gyroscopic effects, etc

Typically used for wind turbine blades

• Modal flexibility (ADAMS/Adwimo)

Import flexible body from FEA

Nastran, Marc, Abaqus, Ansys, I-DEAS

Craig-Bampton modes exported to

Adams

Represents linear elastic flexible body

Modal stress recovery

FEA MBS

Modal

reduction

• Single modeling procedure• Conceptual design

• Beams & masses

• Finite element models (isotropic)

• Detailed design phase• Real-life finite element models

• Isotropic & composites

• Multiple design objectives

• Wind turbine dynamics

• Stress design

• Single enterprise model

• Benefits• Shorter simulation cycles

• Faster virtual testing

MSR

CADFEpre

FEmesh

FEA(k,m) K,M

MBD

F, MFE

statics

σ-ply

q(t)

Blade Modeling with Flexible Bodies

ADAMS Flexible Bodies

• ADAMS/Durability• Features stress display

• Hotspot identification

• Output to durability SW

• NASTRAN stress recovery

• FE-postprocessors

• Composite design tools

• Loading effects considered• Aerodynamic forces

• Gravity

• Centrifugal forces

• Coriolis acceleration

• Gyroscopic moments

• Point loads

• Joints, springs, etc.

• Thermal loads

2009-07-30 36

Design Point Analyze for Complex Subsystem(Using Multi-Body Dynamic)

Linearization

• Large library of modeling elements

• Accurate handling of constraints:

– Time dependencies

• Frequency domain analysis with the linear model

Mode

Frequency, Hz at rotor speed of

0 rpm 660 rpm

Exper. Nastran ADAMS Exper. Nastran ADAMS

1st flap 10.7 11.53 11.53 28.8 29.62 29.84

2nd flap 32.6 36.38 36.36 51.75 55.69 55.73

1st chord 41.0 42.44 42.41 49.1 49.1 49.38

3rd flap 67.8 76.80 76.77 91.5 96.52 96.38

1st torsion 110.3 102.05 102.05 115.0 102.53 102.33

Mode

Frequency (rad/s)

ADAMS RCAS

1 1.178 1.186

2 1.256 1.271

3 2.690 2.765

4 5.164 5.415

5 7.923 7.944

Rotating flexible non-uniform helicopter blade

• Plotting and visualization of response

• Linearization at any operating point

• All inertial effects included:

Gyroscopic, Coriolis, . . .

Offshore wind turbine

Variable cross section helicopter blade from NASA

paper: NASA Technical Memorandum 4760. W. Keats et al. 1997

Paper has numerical results (MSC.Nastran) and experimental

results

MSC.Nastran input deck was used to generate 20 subsystems

imported into ADAMS and stitched using fixed joints

Model was spin to operating velocity and linearizations

performed

Rotor radius 63.5m

Model exported from RCAS to Adams

Good agreement for frequencies w=0, 5, and 15 rad/s

Table shows results for w=5 rad/s

(RCAS is a FEM-based tool for wind turbine simulation,

NREL

Modeling

• User-friendly GUI

• Parametrics

• Generic

• Aerodynamics

NREL/AERODYN

User-defined

ADAMS/Adwimo Toolkit Simulation ; System Level

37

Simulation

• Interactive

• Batch

38

ADAMS/Adwimo Toolkit Simulation ; System Level

Postprocessing

• Numerous interfaces (MD Nastran, MSC.Fatigue, spreadsheet, etc.)

• Graphing + advanced animation features

39

ADAMS/Adwimo Toolkit Simulation ; System Level

Reference, Wind Turbine Industry

7/30/2009 40

• Cener: Adams, Nastran, Patran, Marc, MSC.Fatigue

• NREL: Adams

• Windward Engineering: Adams

• Global Energy Concepts: Adams

• GE Research: Adams

• Gamesa Eólica: Patran & MSC.Nastran

• Ecotecnia: FE-Fatigue

• M-Torres: MSC.Marc, MSC.Mentat, MSC.Fatigue

• Acciona: MSC.Fatigue, Nastran, Patran, Marc

• Mitsubishi Heavy Industries: Adams

• Moog Japan Ltd: Easy5

• Risoe Wind Energy: Patran, Nastran, Marc

• Sandia National Laboratories: Adams, Nastran, Patran

• Matrix/ A.H. Gears/ Windflow Ltd: MSC.Fatigue, Nastran, Patran

• VTT Technical Research Center: Adams

• Center for Wind Energy Research: Adams, Nastran

• NTN: Adams

• Enercon: Patran, Nastran

• Suzlon: Marc, Mentat

• LM Glasfiber: Patran Laminate Modeler

• Kungliga Tekniska Bögskolan: Marc

QnA

1 쪽지 버튼 클릭 2 모든 개설자 선택

3 질문내용 입력 후 보내기 클릭

Thank you!