Study On The Vibration Characteristics And Vibration Attenuation Of Composite Trusses

Composite trusses have the advantages of low density, high specific strength,high specific stiffness, good dimensional stability and so on. It can be used toconstruct the solar array, antenna, space telescope and many other spacecrafts as thesupporting structures. The vibration of composite truss supporting structure willoccur, while many kinds of dynamic loads will be applied on spacecrafts during thelaunching and running process. Accordingly, not only the control of spacecrafts’attitude, the spacecrafts’ positioning accuracy, the antenna’s surface accuracy will beinfluenced, but also the fatigue failure will be accelerated, and the reliability,stability and even security will be decreased. Therefore, it will be of greatsignificance to research on the vibration characteristics and vibration attenuation.Firstly, the vibration characteristics of a typical composite truss was studied inthis paper. Composite pipes’ vibration characteristics were investigated at thebeginning as they are the basic units of composite trusses. The influence of structureparameters and composites layer angle on composite pipes are studied. Furthermore,the vibration characteristics of a typical composite truss are analyzed with the FiniteElement Method. Structure parameters, material parameters and structure pattern’effects on truss’s vibration characteristics, such as pipe thickness, diameters andcomposites layer angles, were investigated.Based on the vibration characteristics research, vibration attenuation of thecomposite truss was studied. The commonly used vibration attenuation method,viscoelastic damping method was adopted. As the computation of dynamicequations of constrained damping composite truss is costly expensive using regularsolving method, the Modal Strain Energy Method (MSE) was used to solve theequations in this paper. The modal loss factors of the constrained dampingcomposite truss’s were calculated, which indicate the structure’s damping value.Additionly, resonance peak response was also calculated. The two parameters wereused to evaluate the different design for vibration attenuation. The effect on thevibration attenuation level of the parameters, such as constrained damping layers’location, damping layer’s thickness, constrained layer’s thickness and viscoelasticdamping material propoties was investigated, used Finite Element Method.It is shown that the constrained damping method is useful to decrease thevibaration of the composite truss, including increasing damping value anddecreasing resonance peak response. The study will be helpful to the largecomposite truss structure design and vibration attenuation design.