An extensive crashworthiness methodology for advanced propulsion systems, Part II: Damage and vibration instability analysis of jet engine forward sections

Bird strike damage in turbofan engines is a serious concern for commercial airlines and engine manufacturers. Novel engine designs, such as those utilizing advanced composite structures in the forward fan assembly, present many challenges in evaluating the crashworthiness of such designs due to the unknown dynamic response characteristics of their structural constituents. Evaluation of jet engines is currently reliant on physical tests which continue to rise in cost and scope as increasingly complex designs must undergo additional scrutiny. A tool is needed for evaluating engine designs that decreases reliance on physical tests. This paper presents the results of a study aim to develop a predictive methodology for evaluating bird strike damage in advanced propulsion systems. The initial degradation and failure of individual fan blades struck by a bird were investigated. Subsequent damage to other fan blades and engine components due to resultant violent fan assembly vibrations and fragmentation was also evaluated. Such methodology is invaluable to the process of design, development and certification of future advanced propulsion systems.