Numerical Modeling and Analyses of a Crankshaft System as a Reciprocating-Airfoil (Ra) Driver for Ra-based VTOL Aircraft

Authors

Mohammad Didarul AlamFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Mechanical Engineering

First Advisor's Name

Yiding Cao

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Ibrahim Nur Tansel

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Bilal El-Zahab

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Armando Barreto

Fourth Advisor's Committee Title

Committee member

Keywords

VTOL, Finite Element Method (FEA), Crankshaft, Connecting rod, Carbon fiber composite, Nonlinear Static analysis, Modal analysis, Vibration, Structural design

Date of Defense

11-9-2022

Abstract

Since the invention of fixed-wing airplanes, they remain the dominant air-transportation vehicles. However, the airplane's massive runway requirement and airport maintenance would hinder its widespread uses without the convenience of the automotive transportation systems. On the other hand, the helicopter was invented more than 80 years ago, but still with very limited civilian air-transportation markets. Helicopters' inherent flight mechanism is too noisy and complex, and poses a compromised safety due to aerodynamic balancing challenges, making them expensive for mass-scale transportation applications. Likewise, despite initially showing promise in terms of small drone/UAV flight demonstration, rotary-fan-driven vertical takeoff and landing (VTOL) technology also failed to become a viable VTOL technology due to fans' poor lifting capability and low energy efficiency. It is anticipated that an efficient VTOL technology would be a stepping stone that will revolutionize the transportation system and overcome the present traffic congestion problem. As a motivation from the existing technological limitations and growing demands, the novel Reciprocating Airfoil (RA) driven VTOL technology has been invented and promises to become an efficient VTOL technology.

The primary objective of this research is to design and develop a crankshaft reciprocating driver for the novel RA-driven VTOL aircraft. The reciprocating driver is a critical component of the novel VTOL technology to produce the long-stroke reciprocating motion of the two wings in an RA aircraft module to generate the necessary lift during takeoff. The nonlinear three-dimensional static models were developed to study the response of the designed reciprocating driver under different working conditions in conjunction with the analytical and rigid body dynamic studies. Additionally, modal and nonlinear eigenvalue analyses have been conducted to avoid possible vibration and buckling failures. The numerical model was validated against the available referenced experimental result. The structural parameters examined include total deformation, von-Mises and maximum principal stresses, and equivalent and maximum principal strains, all of which are acceptable to the present structural design. The average safety factor under the highest loading is above 14. The maximum stress is developed in the corner zone at the junction between the main shaft and the crank web. The close resonance frequency is 26.51 Hz whereas the working frequency of the crankshaft is 12 Hz. As a result, the possibility of resonance is low. The reciprocating driver response during operation under different safety tools and useful design recommendations have been produced, all of which provide archival information for the successful implementation of the crankshaft reciprocating driver. In brief, this research will beacon the development of a new fixed-wing aircraft with an added VTOL capability. Moreover, considering the unique and efficient lifting capability, the RA-driven VTOL technology could also be deployed for drone and unmanned aerial vehicle applications.

Identifier

FIDC010944

Recommended Citation

Alam, Mohammad Didarul, "Numerical Modeling and Analyses of a Crankshaft System as a Reciprocating-Airfoil (Ra) Driver for Ra-based VTOL Aircraft" (2022). FIU Electronic Theses and Dissertations. 5172.
https://digitalcommons.fiu.edu/etd/5172