Time-Domain Analysis of Body Freedom Flutter Based on 6DOF Equation

The reduced weight and improved efficiency of modern aeronautical structures result in a decreasing separation frequency ranges rigid elastic modes. Particularly, high-aspect-ratio flexible flying wing is prone to body freedom flutter (BFF), which coupling the short-period mode with 1st bending mode. Accurate prediction BFF characteristics helpful reflect attitude changes vehicle intuitively design active suppression control law. Instead using mode, this work simulates motion model by six-degree-of-freedom (6DOF) equation. A dynamic mesh generation strategy particularly suitable for simulation free aircraft developed. An accurate Computational Fluid Dynamics/Computational Structural Dynamics/six-degree-of-freedom equation (CFD/CSD/6DOF)-based method proposed. Firstly, time-domain CFD/CSD used calculate static equilibrium state model. Based on state, CFD/CSD/6DOF solved time domain evaluate structural response Then combined variable stiffness method, critical point obtained. This applied calculation results agree well those from modal Nastran software. Finally, analyze influence factors BFF. analysis show that speed can be either releasing plunge constraint or moving center mass forward increasing pitch inertia.