Drivetrain Simulation and Load Determination using … Drivetrain Simulation and Load Determination...

Fakultät Maschinenwesen, Institut für Maschinenelemente und Maschinenkonstruktion, Lehrstuhl Maschinenelemente

Drivetrain Simulation and Load Determination using SIMPACK

SIMPACK Conference – Wind and Drivetrain

Prof. Dr.-Ing. Berthold Schlecht | Dr.-Ing. Thomas Rosenlöcher

Radisson Blu Hotel Hamburg, 7th of October 2015

• Technische Universität Dresden Chair of Machine Elements

• Field of research: drive technology, especially gear technology and components

Technische Universität DresdenChair of Machine Elements

07.10.2015 2Drivetrain Simulation and Load Determination using SIMPACK

• Dynamic analysis of electro-mechanical drive systems• Improvement and verification of simulation techniques• Investigations in the time and frequency domain using the MBS and FEM• Analyses of drive train systems and drive train concepts• Verification of simulation models by measurement results

Technische Universität DresdenChair of Machine Elements


2001 2002 2003 2004 … 2015

approx. 0.7 MW approx. 1.5 MW approx. 2.0 MW

Dynamic analysis of drive systems

roller mill train drive ladle cranes wind turbines

07.10.2015 Drivetrain Simulation and Load Determination using SIMPACK 4

thruster mechanical watches bucket wheel excavator

compressorssteam turbines

Introduction – analysis of wind turbines


global load assumptions (forces/torques at rotor hub, generator)

measurementof forces and torques at awind turbine

simulation of wind loads (CFD, Bladed, Flex5, AeroDyn)

www.purdue.edu

dimensioning: tower, blades, couplings, shafts,gearings, bearings,generator, …

dimensioning: drive train components

standards (DIN 743, ISO 6336) software (mdesign, KissSoft, ..)

finite-element-method (Nastran, Ansys, …)

loads loads

multibody-system simulation (MBS)

calculation of design loads for single components by

recalculation of measured or simulated load cases

? simulation component load ?

determination of design loads for single components by

transfer/ extrapolation of simulated forces and torques

? measurement component load ?

determination of design loads for single components by

transfer/ extrapolation of measured forces and torques



Stepped planetary gear (Multibrid)

Power splitting gear box (MAAG)

Differential gearbox (Bosch Rexroth)



• Student research project: Design and determination of the dynamic behaviour of a multi-staged helical gearbox for wind turbines



Influences of the gear box support concept: three or four point support

Influences of the main frame design on the dynamic behavior of the drive train

• Determination of the distribution of the gearing forces

• Over the width of the gearing• Over one revolution of the planet carrier• Dependent from modelled rotor loads

11.06.2015 9GET Group 2015 SIMPACK Seminar


Weight of the rotor neglected

Analysis for nominal load

forc

e [m

]

Weight of hub and rotor blades considered

Additional modelling of the wind loads

forc

e [m

]

• Specification (NREL 5 MW Baseline): • Rotor diameter:

126 m

• Wind speed: 3 m/s to 25 m/s (11.4 m/s)

• Rotor speed: 12.1 rpm

• Concept: double-feed

asynchronous generator

• Operational range: 670 rpm to 1167 rpm


Design of a 5 MW drivetrain

• First design of the gear box• Scaling of the available 3 MW design without optimisation of ratio split,

number of planets, number of stages, consideration of power splitting or differential gearboxes

• Second design of the gearbox• Optimising of design parameters

• Target:• Comparison of gear box designs


Design of a 5 MW drivetrain

• Implementation of the gearbox in the NREL 5 MW Baseline • Modelling all available degrees of freedom for drive train components• Supporting of components in gearbox housing by bearings• Three-point support of the drive train


NREL 5 MW Baseline – modelling

• Natural frequencies: 1.01 Hz


NREL 5 MW Baseline – frequency domain

• Analysis in the frequency domain



• Analysis in the time domain• Simulation of different load cases• Example:

Wind speed: 12 m/s; 18 m/s; 24 m/s Analysis of the check plots Determination of the loads at the hub Validation of the design of the gear stages

07.10.2015 19

NREL 5 MW Baseline

• Design of an optimised gearbox• Load optimised design

• Mainframe• Gearbox• Planet carriers

• Implementation of the mainframe, the gearbox housing and the planet carriers as modal reduced finite element model


NREL 5 MW Baseline – further steps

• Modelling the gear stages by elastic bodies to analyse:

• Gear twist under torsional load• Effects of body irregularities on the meshing

gear contact• Effects of body deformation on load

distribution and excitation (ring gears, thin gears)

• Effects of flank modifications and pitch error under load

• The tooth loads gets distributes by a referenced MPC’s the tooth flanks for each tooth


Flexible gears SIMPACK 9.8


• Simulation model of the pitch drive• Combination of the detailed gear box and rotor blade model

• Simulation of the pitching process for different wind conditions, analysis of the bearing and gearing forces

• Determination of the natural frequencies and comparison with excitations

Analysis of the pitch drive

+ =



~ 1.3 HzBending mode shape of the rotor blade

~ 15.5 HzTorsional mode shape of the rotor blade


• Simulation model of the azimuth drive• Consideration of the motor and the gear box, the nacelle and the tower

• Simulation of the wind tracking, evaluation of braking concepts, influence of the acting brake torque on the dynamic behaviour

• Analysis of the mode shapes (superposition: tower, azimuth drive, nacelle)




~ 0.4 HzBending mode shape of the tower and torsional mode shape of the drive train

~ 15.5 HzTorsional mode shape of the tower and the drive train

• SIMPACK enables a detailed analyses of wind turbines to determine critical operational states and component loads for the design, certification and optimisation


Conclusion

Technische Universität Dresden

Department of Mechanical Engineering

Institute of Machine Elements and Machine Design

Chair of Machine Elements

Münchner Platz 3D-01062 Dresden

www.tu-dresden.de/me

Thank You for Your Attention


Drivetrain Simulation and Load Determination using … Drivetrain Simulation and Load Determination...

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