Session: 06-03-01: Advances in Aerospace Structures and Materials-1

Paper Number: 166294

Structural Analysis and Development of a 2-Axis Quadcopter Motor Mechanism Using Carbon Fiber Composites 

Recent innovations within aerospace involve more consistent use of polymer matrix composites with high strength-to-weight ratios. One composite with the highest strength to weight is carbon fiber, which is also incredibly stiff. Carbon fiber, carbon fiber composite, or carbon fiber reinforced polymer (CFRP) maintains a high tensile strength along its fibers, which are held in place with a resin or epoxy matrix after a curing cycle. Carbon fiber was proposed for use in this quadcopter design.

Carbon fiber in this proposed quadcopter was used to make up the main airframe structure, holding the flight electronics within the shell body and having proper arm attaching points for the four motors. This quadcopter is unique in containing extra motors and mechanisms with each lifting motor. While carbon fiber may be stronger than steel per unit mass, it exhibits anisotropic material behavior that is challenging to predict. However, given multiple inputs in fiber directions and stackup procedure, it can be specifically tuned to match the application used. This makes carbon fiber complicated to analyze but also highlights a key strength of composites.

Our research project intended to advance composite-material drones' design and performance optimization through a multi-faceted analysis integrating computational fluid dynamics (CFD), rigid-body dynamics, and structural evaluations. In our earlier publication, we focused on a quadcopter equipped with a novel 3-axis rotating mechanism, as previously conceptualized for dynamic thrust vectoring, the design has been validated with its preliminary aerodynamic feasibility and operational efficiency. The design mechanism enables independent propeller rotation around three axes, enhancing maneuverability by dynamically adjusting thrust vectors during flight.

The current paper aims to understand the performance of the drone made of carbon fiber using Finite Element Analysis (FEA) and apply the results to a quadcopter airframe suitable for unique flight characteristics. This study involved using Static structural models through ANSYS Mechanical and explicit dynamics through ANSYS LS-DYNA, along with ANSYS ACP to create the composite structure for analyses. Our study validates the designs of a composite airframe structure suitable for a tiltrotor quadcopter that can survive repeated tests and physical impacts necessary to achieve successful flight.

The results of various structural analyses distinguish this design to maintain acceptable safety factors 5 times above the aerospace industrial standard of 1.2 when in flight. Vibrational analysis ensured no resonant peak frequencies were present within the motor operating range. The crash simulation shows fiber success rates of up to 98% for horizontal impacts around 5 m/s and at drop heights of around 5 m.

Presenting Author: Nicholas Nopwaskey San Jose State University

Presenting Author Biography: I have just obtained my MS in Mechanical Engineering from San Jose State University. I am currently working at a startup nuclear reactor company called Kairos Power as a mechanical design engineer. My employed role and my graduate studies have focused around the use of FEA to evaluate materials beyond standard linear-elastic models. At work I analyze high temperature stainless steel well beyond the creep regime within pressure vessels to make sure they comply with ASME BPVC VIII.2. Within my graduate studies I have looked at composite laminate failure modes/criteria to validate static structural, vibrational, and explicit dynamic impact modeling of a composite airframe.
Within my undergraduate program I obtained my BS in Mechanical Engineering and a minor in Aerospace Engineering at Oregon State University. For senior design I designed, built, tested, and launched a 2-stage, high-powered, solid motor rocket as a structures and integration leader for the team. Our airframe was a combination of carbon fiber and fiberglass composites that we rigorously analyzed and tested coupon samples of the laminate structure to ensure it would survive supersonic flight.

Authors:

Nicholas Nopwaskey San Jose State University
Raymond Yee San Jose State University