Sajad Esmailpour Hamedani - Master of Science in Mechanical Engineering

In this paper, vibration analysis of HDM 312 helicopter blades is investigated. Helicopter blades are considered as rotating Euler - Bernoulli beams. Of course, it must be said there has not been much researches on it so far. The strain energy and kinetic energy and external force relations are attained and put in to the Hamilton s Principle to obtain the equations of motion for the blade. Then, the non-dimensional form of the equations of motion is derived. After that, by applying the Galerkin approach, the flapping natural frequencies are calculated for analyzing the blade. Studying and analyzing rotating beams with loading can be an important step for studying the dynamics and vibration of rotary structures like blades of helicopter and turbines. In this paper, first the mode shapes were obtained. In the continue, by assuming two types of helicopter blade from different materials, and choose a better material for manufacturing structure with higher sensitivity was investigated. These results can be used in various industrial applications or for use in other researches.

Vibrations, Helicopter Blades, Galerkin Approach, Natural Frequencies