Numerical Procedure for Design Optimization of Wind Turbine Drivetrain Using Multibody Gear Dynamics Simulation Considering Wind Load Uncertainty

2016 ◽  
Author(s):  
Huaxia Li ◽  
Hiroyuki Sugiyama ◽  
Hyunkyoo Cho ◽  
K. K. Choi ◽  
Nicholas J. Gaul
Keyword(s):  
Wind Turbine ◽  
Design Optimization ◽  
Gear Tooth ◽  
Numerical Procedure ◽  
Wind Load ◽  
Rolling Contact ◽  
Dynamics Simulation ◽  
Load Uncertainty ◽  
Gear Dynamics ◽  
Wind Load Uncertainty

An accurate prediction of the service life of wind turbine drivetrains is crucial to ensure safe and reliable operation. In particular, gear teeth of the wind turbine multi-stage drivetrain experience severe cyclic rolling contact resulting from highly variable wind loads which are stochastic in nature. Thus, the failure rate of the gearbox is reported to be higher than other wind turbine components. Despite many studies on gear contact and failure analysis of wind turbine drivetrains, limited studies have been carried out regarding gear design optimization considering wind load uncertainty. For this reason, in this study, an integrated multibody gear dynamics simulation procedure for design optimization of the wind turbine drivetrain considering the wide spatiotemporal wind load uncertainty is developed. To this end, the wind load uncertainty model using the joint probability density function of the ten-minute mean wind speed and turbulence intensity, rotor blade aerodynamics, drivetrain dynamics considering the detailed gear tooth contact geometry including the profile modification, and probabilistic contact fatigue failure model are integrated for use in the gear tooth design optimization of wind turbine drivetrains to ensure the expected design life. Several numerical examples are presented to demonstrate the numerical procedure developed in this study.

Dynamic analysis of wind turbine drive train subjected to nonstationary wind load excitation

2014 ◽  
Vol 229 (3) ◽  
pp. 429-446 ◽  
Author(s):  
P Srikanth ◽  
AS Sekhar
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Dynamic Model ◽  
Gear Tooth ◽  
Wind Load ◽  
Drive Train ◽  
Applied Torque ◽  
Frequency Domains ◽  
Turbine Drive ◽  
Time And Frequency Domains

The dynamic analysis of wind turbine drive train is presented in this paper. A typical wind turbine drive train consists of a rotor, gearbox and generator. The dynamic modelling of epicyclic gearbox that exists in wind turbine is challenging due to the fact that it has both rotating and orbiting gears. The dynamic equations of motion are obtained based on the rigid multibody modelling with discrete flexibility approach by Lagrange’s formulation. The dynamic model accounts for the time varying gear tooth mesh stiffness, linear stiffness of bearings and torsional shaft stiffness. The aerodynamic torque that a wind turbine drive train subjected to, is modelled based on the simplified method for load calculation in wind turbine, Danish Standard DS472. The characteristic load value acting per unit length at the two-thirds length of the blade is used for calculating the total load of the torsional moment. The vibration signals that are obtained from wind turbine drive train are nonlinear and nonstationary in nature. This is due to the fact that the applied torque load on drive train is nonlinear and nonstationary in nature. The coupled dynamic model of 18 degrees of freedom is solved for responses in time and frequency domains for some nonstationary wind load realizations. The dynamic responses of the system, contact forces between gear tooth pairs in time and frequency domains are obtained numerically. The study envisages that this dynamic model of wind turbine drive train is very useful for subsequent studies on condition monitoring.

scholarly journals The Indentation Rolling Resistance in Belt Conveyors: A Model for the Viscoelastic Friction

Lubricants ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 58 ◽  
Author(s):  
Nicola Menga ◽  
Francesco Bottiglione ◽  
Giuseppe Carbone
Keyword(s):  
Contact Problem ◽  
Finite Thickness ◽  
Numerical Procedure ◽  
Contact Problems ◽  
Accurate Solution ◽  
Rolling Contact ◽  
Viscoelastic Layer ◽  
Force Coefficient ◽  
Belt Conveyors ◽  
Energy Dissipated

In this paper, we study the steady-state rolling contact of a linear viscoelastic layer of finite thickness and a rigid indenter made of a periodic array of equally spaced rigid cylinders. The viscoelastic contact model is derived by means of Green’s function approach, which allows solving the contact problem with the sliding velocity as a control parameter. The contact problem is solved by means of an accurate numerical procedure developed for general two-dimensional contact geometries. The effect of geometrical quantities (layer thickness, cylinders radii, and cylinders spacing), material properties (viscoelastic moduli, relaxation time) and operative conditions (load, velocity) are all investigated. Physical quantities typical of contact problems (contact areas, deformed profiles, etc.) are calculated and discussed. Special emphasis is dedicated to the viscoelastic friction force coefficient and to the energy dissipated per unit time. The discussion is focused on the role played by the deformation localized at the contact spots and the one in the bulk of the thin layer, due to layer bending. The model is proposed as an accurate solution for engineering applications such as belt conveyors, in which the energy dissipated on the rolling contact of idle rollers can, in some cases, be by far the most important contribution to their energy consumption.

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