Journal of Applied Science and Engineering

Published by Tamkang University Press

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Yi-Ren Wang This email address is being protected from spambots. You need JavaScript enabled to view it.1 and Tseng-Hwa Tsao1

1Institute of Aerospace Engineering Tamkang University Tamsui, Taipei, Taiwan 251, R. O. C.


 

Received: July 4, 2001
Accepted: August 10, 2001
Publication Date: September 1, 2001

Download Citation: ||https://doi.org/10.6180/jase.2001.4.3.04  


ABSTRACT


In this research, the mixed mode fracture of a pair of highly rotating metallic blades has been investigated at room temperature using single edge notched specimens. A set of 2-bladed rotor is driven by a 220 volt AC motor and the rotating speed is fixed at 850 rpm. The notch is located in various blade positions from blade root to tip. The correlation of notch cracks at blade leading edge and trailing edge is also studied. A simple theoretical model of a flapping Bernoulli-Euler-Beam like rotor blade model is established for analytic study. The experimental results show that the cracks grow faster in the case of the rotor blade with higher pitch angle. The analytic study of blade flapping motion also shows the importance of the aerodynamic force in rotating machines. It is suggested that the aerodynamic force should be included in solving the rotating fracture problems.


Keywords: Crack Growth, Fracture, Rotating Beam, Aerodynamic Force, Helicopter Rotor Blades


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