Investigation of UAS ingestion into high-bypass engines, Part I: Bird vs. drone

Foreign Object Ingestion (FOI) is a major threat to air-breathing propulsion systems. The interaction between an ingested object and the propulsion system can jeopardize safety. For modern engines using composite fan blades with advanced aerodynamic geometry, this damage can potentially be elevated, since composite materials are generally more brittle than metal alloys used in the aerospace industry. Furthermore, the post impact residual strength of composite materials is often not substantial enough to endure the continuous rotation after severe impacts. Currently, the industry is faced with a new threat, rogue unmanned aircraft systems (UAS), routed in their widespread and exploding usage in professional and recreational capacities. Thus far, FOI research to guide propulsion design and certification processes has focused on either bird or ice ingestion. Due to yet to be explored dangers posed by UAS, the present work attempts to investigate the extent of any potential damage. Emphasis is placed on the detailed analysis of structural response and damage mechanics of a high-bypass turbojet engine subject to drone ingestion. The simulation results are compared with numerical bird ingestions to draw parallels and investigate the applicability of the existing bird ingestion regulations to drone ingestion scenarios. The results of the investigations extended to a larger sub-class of UAS, representative of commercially available models, are discussed in Part II of the paper.