Study On Dynamics For Flexible Structure In Non-Inertial Frame

In this dissertation, the flexible structure dynamics model in non-inertial frame with large overall motions is analyzed. This problem is the research base of dynamics of flexible multibody system. On the foundation of nonlinear displacement field, the FEM discrete method is applied, and the Kane's method is utilized in deriving the equations of motion. During the solving of the equations, the "stiff' problem is found in the equations. The solution of stiff ordinary differential equations is studied. The results, which are gained by solving the stiff system, validate the theory and the method that are presented in this dissertation.In chapter 1, the engineering background of dynamics of flexible multibody system is introduced, and the research aim and contents of this dissertation are put forward. The modeling theories on dynamics of flexible multibody system are reviewed.In chapter 2, the geometric nonlinear relationship between strain and displacement is utilized in describing the nonlinear displacement field. The FEM discrete model of the arbitrary flexible beam in non-inertial frame is derived by the Kane's method. This method is substantiated by three examples.The same method of chapter 2 is applied in chapter 3...The FEM discrete method is applied to plate. The example of simply-supported plate can substantiate the FEM discrete method is fit for flexible multibody system.. The definition and solution of stiff ODEs is introduced In chapter 4. From the theory of stiff system, the physical and mathematical difference between the discrete method of mode shape and the FEM discrete method can be discovered.