Simulation of helicopter rotor hub vibration reduction using passive method within a workflow integrated environment

Kurzfassung

Rotor blade vibration is one of the major hazards for the helicopter affecting the flight’s performance. For this purpose, an optimization procedure was developed which involves integrating VAST (Versatile Aerodynamic Simulation Tool) into the workflow-integrated environment RCE (Remote Control Environment) and using a Single-Objective Genetic optimization algorithm as the optimizer. Initially, to test the optimizer and process of optimization and integration of tools in RCE, an experiment is carried out by integrating Fusion 360 and FreeCAD. The idea behind the integration of Fusion 360 for CAD modelling and FreeCAD for FEA of the CAD model imported from Fusion 360 to perform optimization where the Objective is to retain minimal material which is sufficient to withstand the stresses. The design variables for the optimization process are the diameter of the circular hole, the distance between the center of the coordinate system and the center of the hole towards the X direction, and the distance between the center of the coordinate system and the center of the hole towards the Z direction. To achieve the best parameters and best design variables for the optimization process both Single Objective Genetic Algorithm and Evolutionary Algorithm are used. The best parameters and best objective function are achieved through a Single Objective Algorithm in RCE. The whole optimization process for minimal rotor blade vibration is performed by carrying out three experiments at the forward flight descent condition by placing three tuning masses whose total weight is the summation of 10% weight of the rotor blade. The experiments carried out for minimizing the objective function are by placing the three tuning masses at varying locations on the elastic axis of the rotor blade, the other experiment when the masses are placed offset to the elastic axis at varying positions, and the last experiment when the masses placed offset to the elastic axis at varying locations with varying twist angle. The design variables are the three masses, the locations on the rotor blade, the distance offset to the elastic axis, and the twist angle. The resulting best objective function is compared to the objective function with the baseline condition where the masses are not placed on the helicopter rotor. The results from the experiments to achieve the vibration reduction using tuning masses are successful. The objective function has been minimized by 65.37% as compared to the baseline objective function.