Aircraft static aeroelastic response analysis based on nonlinear experimental aerodynamic data

As a function of flight dynamic pressure, angle of attack, deflection of horizontal tail and longitudinal acceleration, the longitudinal static aeroelastic response characteristics of an aircraft are analyzed by using two static aeroelastic analysis methods, i.e. the linear static aeroelastic analysis method based on the double-lattice lifting surface theory and the nonlinear one, which is furnished with nonlinear rigid aerodynamic forces by wind tunnel tests and then flexed by a linear aerodynamic influence coefficient matrix. After having compared the calculated results obtained through either of the two analysis methods with the results of the flight tests, it is pointed out that: (1) By using the rigid test aerodynamic forces, the nonlinear static aeroelastic analysis method could offer the results in better conformity with those from the flight tests. (2) Of the analysis results through the linear static aeroelastic analysis method, the bending deformation of wings and some other parameters such as shear forces, bending moments and the torsional moments of wings could be used for primary reference in designing an aircraft, however, the elastic increments of the aerodynamic coefficient, the torsional deformation of wings, the elastic elements of the shear forces, the bending moments and the torsional moments could not be regarded as a correct guide for aircraft design. (3) The aerodynamic coefficient varies with dynamic pressures always linearly, no matter what a rigid aerodynamic force may be linear or nonlinear.