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Combined Effects of Gravity, Bending Moment, Bearing Clearance, and Input Torque on Wind Turbine Planetary Gear Load Sharing: Preprint

Description: This computational work investigates planetary gear load sharing of three-mount suspension wind turbine gearboxes. A three dimensional multibody dynamic model is established, including gravity, bending moments, fluctuating mesh stiffness, nonlinear tooth contact, and bearing clearance. A flexible main shaft, planetary carrier, housing, and gear shafts are modeled using reduced degrees-of-freedom through modal compensation. This drivetrain model is validated against the experimental data of Gear… more
Date: September 1, 2012
Creator: Guo, Y.; Keller, J. & LaCava, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Final Technical Report: Supporting Wind Turbine Research and Testing - Gearbox Durability Study

Description: The combination of premature failure of wind turbine gearboxes and the downtime caused by those failures leads to an increase in the cost of electricity produced by the wind. There is a need for guidance to asset managers regarding how to maximize the longevity of their gearboxes in order to help keep the cost of wind energy as low as possible. A low cost of energy supports the US Department of Energy's goal of achieving 20% of the electricity in the United States produced by wind by the year 2… more
Date: April 30, 2012
Creator: Malkin, Matthew
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLE POURED MAY 4, 2012

Description: The Mixed Oxide Fuel Fabrication Facility (MFFF) will use Colemanite bearing concrete neutron absorber panels credited with attenuating neutron flux in the criticality design analyses. The Savannah River National Laboratory is tasked with measuring the total density, partial hydrogen density, and partial boron density of the colemanite concrete. Sample 04 May 12/Test/S1-1, S1-2, and S1-3 was received on 5/9/2012 and analyzed. The total density measure by the ASTM method C 642 was 2.00 g/cm{sup … more
Date: June 14, 2012
Creator: Cozzi, A.; Best, D. & Reigel, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Development of Open Water-lubricated Polycrystalline Diamond (PCD) Thrust Bearings for Use in Marine Hydrokinetic (MHK) Energy Machines

Description: Polycrstalline diamond (PCD) bearings were designed, fabricated and tested for marine-hydro-kinetic (MHK) application. Bearing efficiency and life were evaluated using the US Synthetic bearing test facility. Three iterations of design, build and test were conducted to arrive at the best bearing design. In addition life testing that simulated the starting and stopping and the loading of real MHK applications were performed. Results showed polycrystalline diamond bearings are well suited for MHK … more
Date: November 28, 2012
Creator: Cooley, Craig, H.; Khonsari, Michael,, M & Lingwall, Brent
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Final Technical Report Recovery Act: Online Nonintrusive Condition Monitoring and Fault Detection for Wind Turbines

Description: The penetration of wind power has increased greatly over the last decade in the United States and across the world. The U.S. wind power industry installed 1,118 MW of new capacity in the first quarter of 2011 alone and entered the second quarter with another 5,600 MW under construction. By 2030, wind energy is expected to provide 20% of the U.S. electricity needs. As the number of wind turbines continues to grow, the need for effective condition monitoring and fault detection (CMFD) systems bec… more
Date: May 29, 2012
Creator: Qiao, Wei
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

THERMOGRAVIMETRIC CHARACTERIZATION OF GLOVEBOX GLOVES

Description: An experimental project was initiated to characterize mass loss when heating different polymer glovebox glove material samples to three elevated temperatures, 90, 120, and 150 C. Samples from ten different polymeric gloves that are being considered for use in the tritium gloveboxes were tested. The intent of the study was to determine the amount of material lost. These data will be used in a subsequent study to characterize the composition of the material lost. One goal of the study was to dete… more
Date: February 29, 2012
Creator: Korinko, P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

NREL Collaborates to Improve Wind Turbine Technology (Fact Sheet)

Description: NREL's Gearbox Reliability Collaborative leads to wind turbine gearbox reliability, lowering the cost of energy. Unintended gearbox failures have a significant impact on the cost of wind farm operations. In 2007, the National Renewable Energy Laboratory (NREL) initiated the Gearbox Reliability Collaborative (GRC), which follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers, and consultants. The project combines analysis, field testing, dynamometer testi… more
Date: January 1, 2012
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Wind Turbine Gearbox Condition Monitoring Round Robin Study - Vibration Analysis

Description: The Gearbox Reliability Collaborative (GRC) at the National Wind Technology Center (NWTC) tested two identical gearboxes. One was tested on the NWTCs 2.5 MW dynamometer and the other was field tested in a turbine in a nearby wind plant. In the field, the test gearbox experienced two oil loss events that resulted in damage to its internal bearings and gears. Since the damage was not severe, the test gearbox was removed from the field and retested in the NWTCs dynamometer before it was disassembl… more
Date: July 1, 2012
Creator: Sheng, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

An Experimental and Theoretical Investigation of Micropiiting in Wind Turbine Gears and Bearings

Description: In this research study, the micro-pitting related contact failures of wind turbine gearbox components were investigated both experimentally and theoretically. On the experimental side, a twin-disk type test machine was used to simulate wind turbine transmission contacts in terms of their kinematic (rolling and sliding speeds), surface roughnesses, material parameters and lubricant conditions. A test matrix that represents the ranges of contact conditions of the wind turbine gear boxes was defin… more
Date: March 28, 2012
Creator: Kahraman, Ahmet
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Determining Wind Turbine Gearbox Model Complexity Using Measurement Validation and Cost Comparison: Preprint

Description: The Gearbox Reliability Collaborative (GRC) has conducted extensive field and dynamometer test campaigns on two heavily instrumented wind turbine gearboxes. In this paper, data from the planetary stage is used to evaluate the accuracy and computation time of numerical models of the gearbox. First, planet-bearing load and motion data is analyzed to characterize planetary stage behavior in different environments and to derive requirements for gearbox models and life calculations. Second, a set of… more
Date: April 1, 2012
Creator: LaCava, W.; Xing, Y.; Guo, Y. & Moan, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Calibrating Accelerometers Using an Electromagnetic Launcher

Description: A Pulse Forming Network (PFN), Helical Electromagnetic Launcher (HEML), Command Module (CM), and Calibration Table (CT) were built and evaluated for the combined ability to calibrate an accelerometer. The PFN has a maximum stored energy of 19.25 kJ bank and is fired by a silicon controlled rectifier (SCR), with appropriate safety precautions. The HEML is constructed out of G-10 fiberglass and is designed to accelerate 600 grams to 10 meters per second. The CM is microcontroller based running Ar… more
Date: May 13, 2012
Creator: Timpson, Erik
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Finite-element analysis of the deformation of thin Mylar films due to measurement forces.

Description: Significant deformation of thin films occurs when measuring thickness by mechanical means. This source of measurement error can lead to underestimating film thickness if proper corrections are not made. Analytical solutions exist for Hertzian contact deformation, but these solutions assume relatively large geometries. If the film being measured is thin, the analytical Hertzian assumptions are not appropriate. ANSYS is used to model the contact deformation of a 48 gauge Mylar film under bearing … more
Date: January 1, 2012
Creator: Baker, Michael Sean; Robinson, Alex Lockwood & Tran, Hy D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Use of Textured Surfaces to Mitigate Sliding Friction and Wear of Lubricated and Non-Lubricated Contacts

Description: If properly employed, the placement of three-dimensional feature patterns, also referred to as textures, on relatively-moving, load-bearing surfaces can be beneficial to their friction and wear characteristics. For example, geometric patterns can function as lubricant supply channels or depressions in which to trap debris. They can also alter lubricant flow in a manner that produces thicker load-bearing films locally. Considering the area occupied by solid areas and spaces, textures also change… more
Date: March 1, 2012
Creator: Blau, Peter Julian
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Full Life Wind Turbine Gearbox Lubricating Fluids

Description: Industrial gear box lubricants typically are hydrocarbon based mineral oils with considerable amounts of additives to overcome the lack of base fluid properties like wear protection, oxidation stability, load carrying capacity, low temperature solidification and drop of viscosity at higher temperatures. For today's wind turbine gearboxes, the requirements are more severe and synthetic hydrocarbon oils are used to improve on this, but all such hydrocarbon based lubricants require significant amo… more
Date: February 28, 2012
Creator: Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Gearbox Reliability Collaborative Gearbox 1 Failure Analysis Report: December 2010 - January 2011

Description: Unintended gearbox failures have a significant impact on the cost of wind farm operations. In 2007, NREL initiated the Gearbox Reliability Collaborative (GRC). The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database in a multi-pronged approach to determine why wind turbine gearboxes do not achieve their expected design life. The collaborative of manufacturers, owners, researchers, and consultants f… more
Date: February 1, 2012
Creator: Errichello, R. & Muller, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Dynamic Analysis of Wind Turbine Planetary Gears Using an Extended Harmonic Balance Approach: Preprint

Description: The dynamics of wind turbine planetary gears with gravity effects are investigated using an extended harmonic balance method that extends established harmonic balance formulations to include simultaneous internal and external excitations. The extended harmonic balance method with arc-length continuation and Floquet theory is applied to a lumped-parameter planetary gear model including gravity, fluctuating mesh stiffness, bearing clearance, and nonlinear tooth contact to obtain the planetary gea… more
Date: June 1, 2012
Creator: Guo, Y.; Keller, J. & Parker, R. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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