<p>Students taking traditional undergraduate level engineering courses not only struggle with highly complex concepts but also struggle in linking the physical meaning of the derived mathematical equations. Although laboratories are an essential part of the engineering curriculum, not all classes have laboratory sections and students take the laboratories in another semester. In this study, we developed a stand-alone and user-friendly Matlab Simscape Graphical User Interface (GUI) program to visualize the concepts presented in the undergraduate level helicopter dynamics course. The developed GUI program enables students to change the parameters of the blade including the rotor radius, blade chord, type of airfoil, material properties, the weight of the aircraft and analyze the effect of the parameter on the performance of the helicopter rotor. The program uses motion dynamics to simulate the blade movement in hover and forward flight. The Simspace GUI program is composed of four modules starting with a simplistic beam model and then increasing infidelity to include radially and azimuthally distributed force. In the first module, the blade is considered as a simple cantilever beam where an input point load is applied at the tip of the blade either vertically down or at an angle. The output of the model predicts the blade deflection as a result of the input point load. In the second module, the force is replaced by a radially distributed load that simulates lift distribution along the span of the blade. The model predicts the blade deflection as a function of time. In the third module, the distributed load is applied to various types of airfoils ranging from symmetrical NACA airfoil to supercritical airfoils. The required data is exported for each blade design and imported into Matlab to fit a function in the form of a 5<sup>th</sup> order sum of sines. The fitted functions are utilized to calculate the airfoil section lift and drag coefficients () for the corresponding angle of attack based on the selected NACA airfoil selection. Blade Element Momentum (BEM) theory is used where the blade is divided radially into several segments. For each segment of the blade, tangential and perpendicular velocities are calculated. These are used to determine the sectional lift and drag loads. Additionally, sectional thrust, and power are calculated. These sectional loads are integrated radially to determine the overall thrust and power of the rotorcraft. In the fourth model, the sectional velocities vary as a function of azimuth, and the forward-moving rotor is simulated. The distributed load varies in forward flight depending on the azimuth location of the blade. For all these sub-sections in the GUI program, rotor deflections are calculated and compared. Once the GUI is run, students see the motion of the blade through the mechanical explorer window while able to export the calculated outputs in the workspace to further analyze the magnitude of deflection as a function of radius, azimuth location of the blade, and time.</p>

Visualizing Fundamental Concepts Taught in Helicopter Dynamics Course Using Matlab Simscape GUI Program

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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