Impact analysis of lightweight drones on business jet engine fan blades

• Main Author: Beh, Ming Wei
• Other Authors: Chow Wai Tuck
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Aeronautical engineering::Accidents and air safety
• Online Access: https://hdl.handle.net/10356/149277
• Institution: Nanyang Technological University

In recent years, the increase trend of flying unmanned aerial vehicles (UAV) has been a concerned for aviation authorities with aircraft drone collisions and drone sightings at restricted airspaces. As such, regulations were imposed to govern the use of UAVs. However, under the Federal Aviation Administration (FAA) guidelines, lightweight drones not exceeding the takeoff weight of 250 g can be flown for recreational purposes without any form of registration. Similarly, the European Union Aviation Safety Agency (EASA) announced that a Flying ID is required for all drones exceeding 250 g. Some research papers have thus studied the impact analysis of lightweight drones on large commercial jet engines, and they have concluded that the damage inflicted is insignificant. However, the same cannot be concluded for smaller engines found in business jets that are smaller and thus have thinner fan blades. Business jets are also commonly found in private or regional airports with less security compared to international airports. Hence, this paper will focus on lightweight drone impact collisions on business jet engines using ANSYS Explicit Dynamics for high-velocity impact simulation. Firstly, a CFM 56-3 fan blade model was designed, and it successfully exhibited a realistic blade deformation result in a bird ingestion test. The fan blade from the PW305 business jet engine was subsequently designed, and the UAV collision test with a lightweight drone (DJI Mavic Mini 2) was simulated at different blade span position. Results show that some material failure can occur at the leading edge of the fan blade and these were caused by the denser and heavier drone components. Additionally, UAV strike analysis on multiple blades were analyzed to illustrate the extent of damage to a business jet engine. Results demonstrated that the lightweight drone collisions can cause minor material failure at up to 15% of the leading-edge blade span, and this was primarily caused by the 45° and 90° impact position of the drone with respect to the engine. Multiple blades were damaged and this can affect engine thrust production. Moreover, drone parts that broke off have also entered the jet engine which can cause internal engine disruption and damage acoustic liners surrounding the fan blades. While further research is needed to corroborate current results, the preliminary findings warrant more research to re-evaluate the harmlessness of lightweight drones.