Structural reliability analysis of rotor blades in ultimate loading

摘要

The objective of the present work is the assessment of the reliability level of an already designed blade according to IEC 61400-1 ed3 implementing two different probabilistic approaches: the Edgeworth Expansion (EDW) and the Response Surface Method combined with Monte Carlo (RSM/MC). An existing probabilistic tool for the reliability analysis of rotor blades based on the EDW method has been further improved and enhanced by implementing also the RSM/MC approach. The analysis is performed at the ply level where material properties are also certified. Stress analysis is implemented using THIN, a numerical tool based on thin wall multi-cellular -beam sections. Material properties and extreme loads (stress resultants acting on the blade section) are considered as stochastic variables. The stochastic nature of all six stress resultants is taken into account and is estimated through available aero-elastic calculations. Correlations among the stress resultants are considered. Due to the high speed stress analysis of THIN, a straightforward comparison of the methods is performed with direct Monte Carlo simulation.