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| Selection and evaluation method for distribution assumption to aircraft buffet load based on statistics and rough set theory |
| YANG Zhi-chun, CHEN Shuai, LI Bin |
| School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China |
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Abstract Aimed to fatigue spectrum development, buffet fatigue life estimation, strength certification, aircraft buffet problems are investigated by means of establishing a statistical distribution model of peak (or valley) values. But the selection of probabilistic distribution model makes evident effects to determine ultimate load cases, buffet cycles and amplitude distributions at a given flight condition. Five typical models, Normal Distribution, Lognormal Distribution, Weibull Distribution, Rayleigh Distribution and Extreme Value Distribution, which are usually used to describe the probabilistic distribution of peak (or valley) values of buffet fatigue loading, are discussed firstly. Based on the probabilistic distributions by parameters estimation, a distribution fitting index is proposed to evaluate the probabilistic distribution assumptions. Then the analysis is carried out by considering their matching levels between the distribution characteristics and the requirements of buffet loading data processing. The minimum discernible interval and maximum resolution are acquired by the theory of rough set to eliminate judgment mistakes. Numerical example proves that this method can meet the requirement of evaluating probabilistic distribution assumptions well.
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Received: 18 October 2010
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Corresponding Authors:
YANG Zhi-chun
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2012, Vol. 31 
