Gust response analysis of flexible aircraft with aerodynamic nonlinearity

Aiming at the gust response of high aspect ratio flexible aircraft, the unsteady aerodynamic considering the nonlinear effect at high angle of attack (AOA) was calculated in time domain by combining the modified Theodorsen method with the strip theory. Based on the nonlinear aerodynamic in time domain, the aeroelastic model of high aspect ratio flexible aircraft with gust disturbance was established, and a novel method applied to gust response analysis with nonlinear aerodynamic was integrally developed. The method was validated by carrying out numerical simulation and method validation basing on a general flexible aircraft, and the gust induced load at wingtip and center of gravity (CG) were compared between linear and nonlinear cases. Numerical results show that the nonlinear effect of aerodynamic at high AOA obviously influences the gust response of the flexible aircraft, and the gust induced load at wingtip reduces as much as 41.7% compared with linear case. The aerodynamic nonlinear effect cannot be ignored for flexible aircraft.