Influence of simulation model detail on determinable natural frequencies and loads

Dr.-Ing. Thomas Rosenlöcher Institute of Machine Elements and Machine Design Chair of Machine Elements Influence of simulation model detail on determinable natural frequencies and loads Dassault Systèmes User Conference 4. 6. Dezember, 2018 Congress Park Hanau

Content Introduction Influence of the level of detail of a simulation model on the simulation results 1st example: 400 tons ladle crane 2nd example: 5 MW wind turbine Conclusion Page 2

Chair of Machine Elements - Field of research Drive technology, especially gear technology and components Load carrying capacity of gearings Calculation procedures, standards, rules (e.g. DIN 743) Software for simulation and calculation of machine elements Machine diagnostics and operational measurements Dynamic analysis of electromechanical drive systems Page 3

Dynamic analysis of electro-mechanical drive systems 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 Page 4

Dynamic analyse of electro-mechanical drive systems Folie 5

Content Introduction Influence of the level of detail of a simulation model on the simulation results 1st example: 400 tons ladle crane 2nd example: 5 MW wind turbine Conclusion Page 6

Analysis of a 400 t ladle crane drive train Overhead crane with 4 welded box girder Span width 22 m, service weight: 770 t Page 7

Analysis of a 400 t ladle crane drive train Frequency domain, natural frequency at 0.4 Hz Page 8

Analysis of a 400 t ladle crane drive train Frequency domain, natural frequency at 63.7 Hz Page 9

Analysis of a 400 t ladle crane drive train Influence of the level of detail of the simulation model to the torsional natural frequencies level of detail of the model variant V6 V5 V4 V3 V2 V1 modelled as modal reduced FE-model supporting structure X main gearbox X X drum gearbox X X gearbox, 6 degrees of freedom X X degrees of freedom of drivetrain components equatorial rotat. axes X X X radial displacement X X X X axial displacement X X X X X polar axis of rotation X X X X X X calculated natural frequencies 1 st torsional natural frequency [Hz] 26.3 29.3 30.4 30.6 30.7 30.7 2 nd torsional natural frequency [Hz] 31.1 30.5 33.5 38.0 48.3 48.5 3 rd torsional natural frequency [Hz] 31.9 33.5 37.0 45.1 50.9 51.9 4 th torsional natural frequency [Hz] 48.6 52.0 62.6 86.0 143.1 163.3 Page 10

Analysis of a 400 t ladle crane drive train Braking concept Redundant system, consists of operational brakes on the motor sided shafts and emergency stop brakes on the rope drums Load cases to be analysed Reason for the emergency stop Direction of motion Load Emergency stop Upwards Traverse Breakage of a shaft Upwards Traverse and filled ladle Page 14

Analysis of a 400 t ladle crane drive train Load case: emergency stop Load case: shaft breakage (drum sided) Effect of the level of model detailing on the gearing forces in the gear boxes emergency stop shaft breakage Page 15

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Content Introduction Influence of the level of detail of a simulation model on the simulation results 1st example: 400 tons ladle crane 2nd example: 5 MW wind turbine Conclusion Page 17

Analysis of a 5 MW windturbine Implementation of the gearbox in the NREL 5 MW Baseline Three-point support 6 DOF Elastic beams: Rotor blades Tower Shafts Modal reduced finite element models: Planet carriers Gearbox housing Mainframe Page 18

Analysis of a 5 MW windturbine Influence of the level of detail of the simulation model to the torsional natural frequencies variant 1 2 3 4 5 6 7 8 9 10 level of detail of the model modelled as modal reduced finiteelementmodel or SimBeam Tower main frame X X gearing X X X X gearbox housing X X X X planet carrier X X X X X gearbox housing, 6 DOF X X X X X X SimBeam shafts X X X X X X X Drive train components with 6 DOF X X X X X X X X flexible rotor blades X X X X X X X X X calculated natural frequencies 1 st torsional natural frequency [Hz] 1.5 1.5 1.5 1.5 1.5 1.5 1.9 1.9 1.9 11.9 2 nd torsional natural frequency [Hz] 2.7 2.7 2.7 2.7 2.7 2.7 3.4 5.0 5.2 179,3 3 rd torsional natural frequency [Hz] 7.7 7.7 7.7 7.7 7.7 7.8 8.4 15.4 22.9 424,3 4 th torsional natural frequency [Hz] 30.0 30.2 30.6 30.7 30.9 32.3 47.0 55.2 180.8 488,0 5 th torsional natural frequency [Hz] 92,1 92,7 93,9 93,7 96,3 97,5 93,6 150,7 424,6 536,4 Page 19

Analysis of a 5 MW windturbine Comparison of natural frequencies and excitations in a Campbell-diagram Page 24

Analysis of a 5 MW windturbine Comparison of natural frequencies and excitations in a Campbell-diagram Page 25

Analysis of a 5 MW windturbine load distribution analyses Transmission of loads by the gearing of the planetary gear stage External loads cause misalignment of gears due to inclination of carrier against ring, sun gear Simulation of load case in SIMPACK Determination of relative displacement sun planet planet ring Calculation of helix deviation Calculation of load distribution Optimisation of modification New simulation in SIMPACK using optimised modification Page 26

Analysis of a 5 MW windturbine Load distribution over the width of the gearing and rotation of the planet carrier elastically modelled gearing sun planet helix angle modification f Hβ = 90 µm ring planet helix angle modification f Hβ = 250 µm lead crowing C b = 60 µm lead crowing C b = 30 µm SoPl K Hβ PlRi K Hβ flex 1.73 1.48 Page 27

Analysis of a 5 MW windturbine Load distribution over the width of the gearing and rotation of the planet carrier rigidly modelled gearing sun planet helix angle modification f Hβ = 90 µm ring planet helix angle modification f Hβ = 250 µm lead crowing C b = 60 µm lead crowing C b = 30 µm SoPl K Hβ PlRi K Hβ flex 1.73 1.48 rigid 1.91 1.43 Page 28

Conclusion Simulation model must represent all relevant system properties with sufficient accuracy Modelling approach has to adapt to the design of the drivetrain Knowledge of the correct system boundaries often requires a very detailed simulation model The higher effort to assemble a multibody system simulation model offers the possibilities for a deeper understanding of the complete system behaviour Page 29

Thank you for your attention Technische Universität Dresden Faculty of Mechanical Science and Engineering Institute of Machine Elements and Machine Design Chair of Machine Elements Münchner Platz 3 D-01062 Dresden www.tu-dresden.de/me»knowledge builds bridges.«page 30