Helicopter rotor blade modal tuning using internal preloads

Robert Dibble, Branislav Titurus

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

14 Citations (Scopus)
237 Downloads (Pure)


There are many benefits of variable speed rotors if the associated dynamics problems can be alleviated. Existing passive and active methods are unsuitable due to their mass/power requirements and effectiveness over the necessary frequency range. The concept of inducing controlled 'stress softening' to alter the natural frequencies of a rotating structure in a vacuum and in turn avoid resonance is explored in this research. This paper presents an experimental and computational demonstration of this concept in the context of a small scale rotor blade representation. The model is successfully validated away from and within regions of coupling in which veering was present, and was therefore used to assess the effectiveness of the concept on full sized rotorcraft blades. Full scale assessment demonstrated that adequate separation can be achieved without requiring excessively large forces. The aim of the research is to create a semi-active method for the alteration of the blade's resonant frequencies to avoid resonance within a range of rotor speeds.

Original languageEnglish
Title of host publicationProceedings of the ISMA 2016 International Conference on Noise and Vibration Engineering
Place of PublicationLeuven
PublisherKU Leuven, Departement Werktuigkunde
Number of pages14
ISBN (Electronic)9789073802940
Publication statusPublished - 21 Sept 2016
EventISMA 2016 International Conference on Noise and Vibration Engineering - Leuven, Belgium
Duration: 19 Sept 201621 Sept 2016


ConferenceISMA 2016 International Conference on Noise and Vibration Engineering
Internet address


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