Study of the Torsional Phenomena in the Wing Structure of a Quadplane Type UAS

This paper is focused on research regarding the wing torsional phenomena during yaw maneuvers in vertical flight of a utilitarian quad-plane Unmanned Aerial System (UAS). During vertical takeoff or landing sequence, when the heading of the aircraft is corrected by yaw, significant torsional stress is observed in the wing section between the vertical flight motor pylon and main fuselage. The study focuses on FEA (Finite Element Analysis) of the composite wing primary structure, simulating forces when yaw maneuvers are conducted in vertical flight sequence. The primary structure of the wing is composed from ribs and spars manufactured using CFRP (Carbon Fiber Reinforced Polymer). Two scenarios are simulated. Same load conditions are used on two architectures for the primary structure. In the first load case, when load is applied simulating aggressive yaw, the displacement on the structure is
$MAX_{d}=2.747$
mm. Cross ribs were added to the structure in the second analysis. Results show that the cross ribbed structure is stiffer when the loads are applied, with smaller a maximum displacement of
$MAX_{d}=1.615$
mm.