| In this dissertation, rigid-flexible coupling dynamics performance of flexible multi-body systems made of composite material is investigated.Composite material is made by two or more different materials with different properties by physical or chemical method. Composite material possesses special features which the materials compose it don't have. Stiffness, strength and thermal properties of composite material are promoted obviously compared with isotropic material. At present, composite material has been used in aeronautical engineering, astronautical engineering and ship engineering. In order to satisfy the need of the quick development, it is necessary to study the dynamics properties of the flexible multi-body systems made of composite material.The composite material used in this paper is a kind of fiber-reinforced material. It consists of matrix materials and reinforced materials. Since reinforced materials control the mechanical behavior of the whole composite plate, it plays an important part in composite materials. Matrix materials are used to support fiber material and deliver the load among the fibers.In chapter one,the previous research on the dynamics for composite structure considering thermal effect is summarized, and the objectives of this dissertation are put forward. In chapter two, rigid-flexible coupling dynamics for composite beams is investigated. Based on nonlinear strain-displacement relationship, and considering the shear deformation, variational equations of a composite Timoshenko beam are derived by means of the principle of virtual work. The assumed mode method is used to discrete the variational equations to obtain the rigid-flexible coupling dynamic equations for hub-cantilevered-beam system. Firstly, by comparing the dynamic characteristics of composite beam with that of isotropic material beam, the superiority of the composite materials is confirmed, and then the shear effect on the system rigid-flexible coupling dynamics for isotropic and composite materials is investigated. By analyzing the frequency differences between the Timoshenko and Euler-Bernoulli beam models, the applicability of the Euler-Bernoulli beam model to the composite beam is clarified according to the frequency error. Finally, kinematics constraint equations are led into the dynamics equations to derive the closed Lagrange equations of the first kind for composite flexible multi-body systems applied with thermal load based on Cartesian formulation. Different fiber layer-ups sequences on the dynamics performance for crank-slider system are investigated. Simulation results show that due to the additional bending load for a non-symmetric composite beam, additional bending deformation may be excited and influence the vibration characteristics in case that the beam is applied with thermal load or inertial and constraint loads.In chapter three, rigid-flexible coupling dynamics for rectangular composite plate is investigated. According to Mindlin plate theory which includes transverse shear deformation, and based on strain-displacement relationship of a composite plate considering thermal load, the principle of virtual work is used to establish the variation equations for a composite plate undergoing free spatial motions. The finite element method is used to discrete the variation equations to obtain the rigid-flexible coupling dynamic equations for hub-plate system undergoing spatial motion. Modal truncation approach is used to decrease the system degree of freedom. Firstly, the present frequency results are compared with those obtained by MSC.Nastran Software to verify the correctness of the proposed formulation. Then, for each of the isotropic, symmetric composite, anti-symmetric and non-symmetric composite materials, the influence of thermal load on the coupling effect of the stretch, bending, torsion deformations and rotational motion, and the influence of rotational motion on the coupling effect of the bending, torsion deformations and rotational motion are investigated, respectively. Finally, the influence of the layer number on the vibration characteristics of the composite plate is investigated. Simulation results show that the vibration amplitude of the anti-symmetric and non-symmetric plates applied with thermal load decreases significantly with the increase of the layer number, and then an efficient method for eliminating vibration of the composite material is put forward.
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