In this research, the mixed mode fracture of a pair of highly rotating metallic blades has been investigated at room temperature driven by a 220 volt AC motor and the rotating speed is fixed at 850 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 annalistic 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 is solving the rotating fracture problems.
Tamkang Journal of Science and Engineering=淡江理工學刊 4(3)，頁173-182