Design And Vibration Analysis Of Bracing Arm With Viscoelastic Laminated Composite Damper

Due to the limitation of transport cost and internal space of spacecraft, space truss structure is applied more and more extensively in the field of aerospace. In order to complete high-accuracy space mission, the space truss structure must have sufficient vibration control capability. As the support structure of antenna, the structural performance and dynamic characteristics of the bracing arm have great influences on integral performance of spacecraft. The key to passive vibration control of space truss structure is to choose the material and determine the optimal configuration of the dampers.This paper takes cable-strut deployable articulated mast as the object, uses the viscoelastic laminated composite as the material of damper and determines the optimum configuration of damper, finally the structural performance and dynamic characteristics of the mast is optimized; the stiffness and vibration control ability of the mast is enhanced. Consequently, the study in this paper provides theoretical support for application of composite in the field of passive vibration control of truss structure.According to the folding rate model and bending stiffness model of cable-strut deployable articulated mast, combining with the stability theory of rod, the configuration parameters of cable-strut deployable mast made of aluminum alloy are determined. Based on the configuration parameters, the analysis model of unit frame is established in ADAMS, and the theoretical performance value is obtained to certify the feasibility of configuration parameters.Based on the strain energy method, combining with the anisotropy of composite and frequency dependent characteristics of viscoelastic material, the damping model of composite and viscoelastic material is established, and the model is confirmed through comparing analysis data with experimental data. Based on the model, the material and ply sequences of rods in the mast are determined, and stability of the rod made of composite is checked. The optimization function, in which the thickness of viscoelastic layer in viscoelastic laminated composite is taken as argument and equivalent elastic modulus and dynamic loss factor of material is taken as target, is established. The optimum thickness of viscoelastic layer in viscoelastic laminated composite is determined and the viscoelastic laminated composite is taken as damper material. The optimal function of damper configuration is given based on the principle of energy dissipated, thereby the optimum configuration is determined according to the optimal function and distribution trend of modal strain energy. The dynamic response of structure with no damper, structure with damper in the random positions and structure with damper in the optimal positions are compared to validate the effectiveness of configuration scheme. According to the configuration scheme, the viscoelastic laminated composite dampers are allocated in the optimal positions, and the rods in the mast are made of fiber-reinforced composite, thereby the mast made of composite is established.In the last place, the structural performance and dynamic characteristics of mast made of aluminum alloy and mast made of composite are compared comprehensively. It is proved that the mast made of composite has obvious advantages in stiffness and vibration control ability over the mast made of aluminum alloy by comparing the theoretical parameters and results of statics and dynamics analysis under the same excitation.