Dynamic Analysis of Damage to Aircraft Propulsion System Impacted by Exploding Missile

In this paper, an attempt is made to analytically predict the damage to a running turbofan jet engine if it gets hit by an incoming heat-seeking missile. The predictive methodology is based upon developing a LS-DYNA® finite-element model of the entire engine, as well as the exploding missile. The analytical simulation considers both the effect of ballistic energy, as well as the pressure pulse generated as a result of the detonation of the warhead in the missile. The engine model accurately captures the complex dynamic effect of the transient imbalance forces and gyroscopic moments that are caused in a dual concentric rotor system that is spinning at two different speeds. The numerical results presented here are directly applicable in determining the structural damage to individual components of a typical large turbofan jet engine that is used in commercial aviation. The high-velocity impact damage to engine components can involve penetration, fragmentation, and even the uncontained liberation of debris from the rotors. In general, the heat-seeking missile always has a tendency to go toward the engine core, but the impact results in large dynamic loads on the engine mount system.