Simulation on the dynamic stability derivatives of battle-structure-damaged aircrafts

• Published in: Defence technology 2021-06, Vol.17 (3), p.987-1001
• Main Author: Mi, Bai-gang
• Format: Article
• Language: English
• Subjects: Combined dynamic derivative; Computational fluid dynamics (CFD); Continuous rod damage; Flying wing; Fragment damage
• ISSN: 2214-9147; 2214-9147
• DOI: 10.1016/j.dt.2020.06.005

Accurately evaluating the aerodynamic performance of a battle-structure-damaged aircraft is essential to enable the pilot to optimize the flight control strategy. Based on CFD and rigid dynamic mesh techniques, a numerical method is developed to calculate the longitudinal and longitudinal-lateral coupling forces and moments with small amplitude sinusoidal pitch oscillation, and the corresponding dynamic derivatives of two fragment-structure-damaged and two continuous-rod-damaged models modified from the SACCON UAV. The results indicate that, at the reference point set in this paper, additional positive damping is generated in fragment-damaged configurations; thus, the absolute values of the negative pitch dynamic derivative increase. The missing wingtip induces negative pitch damping on the aircraft and decreases the value of the pitch dynamic derivative. The missing middle wing causes a noticeable increase in the absolute value of the pitch dynamic derivative; the missing parts on the right wing cause the aircraft to roll to the right side in the dynamic process, and the pitch-roll coupling cross dynamic derivatives are positive. Moreover, the values of these derivatives increase as the damaged area on the right wing increases, and an optimal case with the smallest cross dynamic derivative can be found to help improve the survivability of damaged aircraft. •The dynamic aerodynamic performance of the battle-damaged aircraft has been firstly investigated by using the rigid dynamic mesh technique.•A method to identify the coupling cross dynamic derivatives of the battle-damaged aircraft has been developed based on small oscillation.•The fragment and the continuous rod damaged models represent the general damage forms on aircraft, and the simulating results can be used to improve survivability of damaged aircraft.