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Dissertation

Effects of variable load and rotational speed conditions on gear micropitting in wind turbine gearboxes

01 Oct 2014-
About: The article was published on 2014-10-01 and is currently open access. It has received 1 citations till now. The article focuses on the topics: Turbine & Rotational speed.
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Journal ArticleDOI
TL;DR: A new algorithm called Mersenne Twister (MT) is proposed for generating uniform pseudorandom numbers, which provides a super astronomical period of 2 and 623-dimensional equidistribution up to 32-bit accuracy, while using a working area of only 624 words.
Abstract: A new algorithm called Mersenne Twister (MT) is proposed for generating uniform pseudorandom numbers. For a particular choice of parameters, the algorithm provides a super astronomical period of 219937 −1 and 623-dimensional equidistribution up to 32-bit accuracy, while using a working area of only 624 words. This is a new variant of the previously proposed generators, TGFSR, modified so as to admit a Mersenne-prime period. The characteristic polynomial has many terms. The distribution up to v bits accuracy for 1 ≤ v ≤ 32 is also shown to be good. An algorithm is also given that checks the primitivity of the characteristic polynomial of MT with computational complexity O(p2) where p is the degree of the polynomial.We implemented this generator in portable C-code. It passed several stringent statistical tests, including diehard. Its speed is comparable to other modern generators. Its merits are due to the efficient algorithms that are unique to polynomial calculations over the two-element field.

5,819 citations

Book
02 Aug 2001
TL;DR: In this paper, the authors discuss failure prevention of failure due to static loading and fatigue failure resulting from variable loading in the design of non-permanent joint components, such as screw heads, fasteners, and nonpermanent joints.
Abstract: Part I Basics1 Introduction2 Statistical Considerations3 Materials4 Load and Stress Analysis5 Deflection and StiffnessPart II Failure Prevention6 Failures Resulting from Static Loading7 Fatigue Failure Resulting from Variable LoadingPart III Design of Mechanical Elements8 Screws, Fasteners, and the Design of Nonpermanent Joints9 Welding, Brazing, Bonding, and the Design of Permanent Joints10 Mechanical Springs11 Rolling-Contact Bearings12 Lubrication and Journal Bearings13 Gears - General14 Spur and Helical Gears15 Bevel and Worm Gears16 Clutches, Brakes, Couplings and Flywheels17 Flexible Mechanical Elements18 Shafts and AxlesA Appendix A Useful TablesB Appendix B Solutions to Selected ProblemsIndex

2,781 citations

Book
01 Jan 1966

555 citations


"Effects of variable load and rotati..." refers methods in this paper

  • ...3 < 1 < 1 The Dowson and Higginson formula (Dowson and Higginson, 1966), can be used in conjunction with the mean surface roughness value of gears in order to determine the specific lubricant film thickness to assess the actual gear flank surface EHL behaviour....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the reliability of wind turbine components from historic German and Danish data has been analyzed using reliability analysis methods which are not only applicable to wind turbines but relate to any repairable system.
Abstract: Modern wind turbines are complex aerodynamic, mechanical and electrical machines incorporating sophisticated control systems. Wind turbines have been erected in increasing numbers in Europe, the USA and elsewhere. In Europe, Germany and Denmark have played a particularly prominent part in developing the technology, and both countries have installed large numbers of turbines. This article is concerned with understanding the historic reliability of modern wind turbines. The prime objective of the work is to extract information from existing data so that the reliability of large wind turbines can be predicted, particularly when installed offshore in the future. The article uses data collected from the Windstats survey to analyse the reliability of wind turbine components from historic German and Danish data. Windstats data have characteristics common to practical reliability surveys; for example, the number of failures is collected for each interval but the number of turbines varies in each interval. In this article, the authors use reliability analysis methods which are not only applicable to wind turbines but relate to any repairable system. Particular care is taken to compare results from the two populations to consider the validity of the data. The main purpose of the article is to discuss the practical methods of predicting large-wind-turbine reliability using grouped survey data from Windstats and to show how turbine design, turbine configuration, time, weather and possibly maintenance can affect the extracted results. Copyright © 2006 John Wiley &Sons, Ltd.

459 citations

Journal ArticleDOI
TL;DR: The results presented demonstrate that the interpretation techniques can provide performance assessment and early fault identification, thereby giving the operators sufficient time to make more informed decisions regarding the maintenance of their machines.
Abstract: This paper describes a set of anomaly-detection techniques and their applicability to wind turbine fault identification. It explains how the anomaly-detection techniques have been adopted to analyse supervisory control and data acquisition data acquired from a wind farm, automating and simplifying the operators' analysis task by interpreting the volume of data available. The techniques are brought together into one system to collate their output and provide a single decision support environment for an operator. The framework used is a novel multi-agent system architecture that offers the opportunity to corroborate the output of the various interpretation techniques in order to improve the accuracy of fault detection. The results presented demonstrate that the interpretation techniques can provide performance assessment and early fault identification, thereby giving the operators sufficient time to make more informed decisions regarding the maintenance of their machines.

425 citations