S Mohammadi - Assistant professor, Faculty of Engineering, University of Kurdistan
A.R Shahani - Professor, Faculty of Mechanical Engineering, K. N. Toosi University of Technology

In structural point of view, a helicopter rotor blade is a cantilever beam which is exposed to different loads during flight. So, the main task of the blade is to tolerate applying stresses in all the loading conditions with minimum weight. In addition, the blade tip displacementshould remain in an acceptable range so that the aerodynamic operation is done well. In other words, for preventing some problems like resonance and flatter, the blade structural stiffness should be large enough. In this article, at the first step, the applied loads on the Bell 205 helicopter main rotor blade in the hover situation will be computed. For obtaining lift distribution along the blade length, the combination of momentum theory and blade element theory was used. After that, pressure distribution on the blade was computed using Aerofoil software and a Matlab code. In the next step, the blade model were created using Abaqus software with all of its detail.Then, the blade stress and deformations are obtained using FEM analysis. Due to the complexity of the model and in order to obtain more accurate results for the stresses, the sub-model technique was used. At the end, the critical point of the blade in structural point of view and the maximum stress in its main load bearing components were obtained.

numerical analysis, helicopter blade stress analysis, helicopter blade loads, helicopter blade FEM analysis, rotor blade stress