空间含铰可展桁架结构的非线性动力学建模与分析

Nonlinear Dynamic Modeling and Analysis for Space Deployable Structure with Clearance Joints

综合考虑间隙、非线性刚度、摩擦及碰撞阻尼,建立了铰链等效模型,并基于该等效模型建立了含铰可展桁架结构动力学模型。根据铰链的变拓扑结构特点,提出了适用于解决时变非线性动力学问题的附加力方法,对多自由度平面和空间可展桁架进行了动力学仿真,得到了可展桁架的动力学响应。通过设置不同铰链参数和外部激振条件,分析了不同间隙、激振力、摩擦力对含铰可展桁架频率和幅值的影响,结果表明:间隙和激振力增大可导致桁架固有频率降低,响应幅值增大;摩擦力增大可提高桁架的固有频率。多单元桁架伸展臂的动力学试验结果验证了文中建立的含铰可展桁架动力学模型的正确性。

An equivalent model of clearance joints is presented by considering clearance,nonlinear stiffness,friction and impact damping.And a nonlinear dynamic model of the space deployable structure is established on the basis of the equivalent model.According to the variable topology characteristics,an additional force method is proposed to solve the nonlinear dynamic equation of the clearance joint structure.Dynamic simulations of the plane and space structures with clearance joints are conducted.Changing joint parameters and vibration condition,the effects of joint clearance,exciting force and friction force on the structure are analyzed.The results show that the natural frequency＇lowers and the amplitude of response magnifies with the increasing clearance size and exciting force,while the natural frequency rises with the increasing friction force.Dynamics experiment of deployable articulated mast verifies the correctness of the model of deployable structure with clearance joints.