AERITRANS COMPANYAbstract of a

Final year project & start-up projectBy

Students : Supervisors :Marouan Selmi Mme Wafa Ben Yahia

Nader Khattabi Mr Fathi DjemalWsifi Bassem Mr Hedi EL-Hamdi

AT-1 HELICOPTER

National Engineering School

of Gabes ENIG

Tunisia

Mechanical Engineering

Departement

Subjects involved in this project are:Finite element methods, fluids mechanical, Computational fluid dynamic CFD, thermodynamics, hydraulic systems, technical design, materials properties, project management, SOLIDWORKS,ANSYS Workbench…

main parts :

Part 1.CFD analysis of a rotor system for a helicopter:Design of the rotor blades based on NACA0012 airfoil

CFD simulation of a 2 blades rotor using Ansys Workbench

Part 2.Study and design of a transmission system for a helicopter:Design of gearboxes and shafts using SolidWorks

Numerical analysis of gearboxes

Stress analysis of gearboxes using Ansys Workbench

Part 3.Design and analysis of a helicopter fuselage and airframe structure:Design of a helicopter fuselage and airframe structure using SolidWorks

CFD analysis of a helicopter fuselage

Structural and modal analysis of a helicopter airframe

27 May 2016

Current achievements in the project: Part 1 . CFD analysis of a rotor system for a helicopter:Design of the blades based on NACA0012 airfoils :

Completed task After careful Studies the design of the helicopter blade was made based on the NACA0012 airfoil, then using Momentum theory and Blade element theory the blade shape was finally designed. The figure below shows the final CAD of the blade.

CFD simulation of a teetering rotor using Ansys Workbench Completed task

Using Ansys Workbench software the previous design of blade was put under several simulations to predict the interaction between the air flow and the blade structure including : turbulence, velocity magnitude, pressure…

Some promising results was also withdrawn from the CFD simulations including: Lift coefficient, drag coefficient, moment… the figure below shows a sample of one of the simulations using Fluent tool in Ansys Workbench.

Contours of pressure coefficient and history convergence of the CFD simulation

Part 2.Study and design of a transmission system for a helicopter:Design of gearboxes and shafts using SolidWorks:

Completed task After designing the fuselage, a design of the transmission system was the second part of this project. The figures below shows the CAD model of gearboxes and shafts using SolidWorks.

Numerical analysis of gearboxes: Completed task

The gearboxes and shafts was then numerically analyzed to make sure they resist the torques and loads applied during several cases (hover, forward flight …). The figures below shows the numerical analysis process using Microsoft Excel and hand calculations.

Numerical analysis using Microsoft Excel

Stress analysis of gearboxes using Ansys Workbench:

Completed task

Adding to the numerical analysis, the transmission components went through stress analysis to predict the possible deformations. The stress analysis was made using transient structural tool in Ansys Workbench. The figure below shows the results of the simulation.

Deformation of a bevel gear using transient structural tool in Ansys Workbench

Deformation of a gearboxes using transient structural tool in Ansys Workbench

Part 3.Design and analysis of a helicopter fuselage and airframe structure:

Design of a helicopter fuselage and airframe structure using SolidWorks:

Completed task

The idea was to design a robust and aerodynamic fuselage that can resist the applied loads. The NASA ROBIN fuselage was the basic start as it gives a great reference in order to be able to compare the results of the CFD simulations of the desired fuselage with the ROBIN fuselage results. You can see in the figure below the preliminary shape of the AT1 helicopter in compare to the ROBIN fuselage.

CFD analysis of a helicopter fuselage: Completed task

After designing the AT1 fuselage several CFD simulations took place in order to predict the air flow around the fuselage therefore improving the aerodynamic shape if needed. The figure below shows one of the CFD simulations process from meshing to results using Ansys Workbench.

ROBIN fuselageAT1 fuselage

Contours of turbulence using K−ε modelin Fluent (Ansys Workbench)

After running the CFD simulations the shape of the fuselage needed to be improved in order to reduce turbulence and drag load. The figure below shows the final shape which was validated later with further simulations.

Structural and modal analysis of a helicopter airframe: Completed task

After designing the fuselage, the airframe of the AT1 was designed based on the shape and dimensions of the fuselage. The airframe was then under several simulations to predict it’s behaviors under static loads. Finally the airframe went through modal analysis to withdraw the first modes that could cause resonance under specific loads. The figures below shows the different states of both static and modal analysis from CAD to mesh to simulations.

Airframe design using SolidWorks

Static deformation of the airframe under loads using static structural tool in Ansys Workbench

Modal analysis of the airframe using modal tool in Ansys Workbench

Current work in the project: (27 May 2016) Currently it is the final step in the project which is the documentation and the essay preparation of the project.