柔性天线低频隔振器设计及动力学仿真分析

发布时间：2019-02-09 12:42

【摘要】：卫星在轨运行时,由于其所处环境十分复杂,当受到来自外界光压、温度、地球引力等的扰动时,会引起柔性天线的低频振动。同时,卫星本体内部的偏心轮以及调姿也会引起低频振动。为避免两者之间低频振动的相互耦合,需设计性能良好的低频隔振器来满足要求。金属弹簧隔振器虽具有较好的低频隔振特性,但因其阻尼小而不能很好的抑制共振峰；橡胶隔振器虽具有较大的阻尼迟滞的特性,但其低频隔振性能较差：本文研究一种由金属橡胶和弹簧组成的复合隔振器,解决柔性天性与卫星本体之间的双向低频隔振问题。首先通过建立金属橡胶和弹簧的力学模型,得出弹簧的变形与高径比关系曲线以及金属橡胶的本构方程,据此设计出隔振器的结构参数。基于Patran与Nastran软件平台,建立了金属橡胶弹簧隔振器的三维模型和有限元模型,分析了隔振器的各阶模态,得到了隔振器的前26阶固有频率及主振型。通过对隔振器施加白噪声激励产生的时域响应分析,验证了隔振器的可行性。然后利用Patran软件建立了包括卫星本体、金属橡胶弹簧隔振器、柔性天线及索网、太阳能帆板的整星多体三维模型和动力学模型。基于MSC.Nastran软件分析了整星的各阶模态,得到了整星系统的前90阶固有频率和主振型。通过在X、Y、Z三方向施加单位脉冲激励,仿真分析了有隔振器连接和无隔振器刚性连接时柔性天线顶端节点的时域响应以及整星系统的频率响应。计算了柔性天线顶端节点在三个方向的隔振率,结果表明：隔振器对2.344Hz、3.32Hz、4Hz、6.6Hz四个共振频率均有良好的隔振性能。其中,z向的隔振效果最好,其振动传递率与无隔振器刚性连接比较,分别减小了65%、86.53%、62.5%(2.344Hz),99.91%、99.56%、99.93%(3.32Hz),85.12%、89.27%、89.13%(4Hz),90.72%、93.17%、30.83%(6.6Hz)。x向次之,振动传递率分别减小了11.48%、66.73%、0.078%(2.344Hz),66.88%、99.41%、99.32%(3.32Hz)、56.55%、66.47%、65.54%(4Hz),79.29%、94.55%、94.07%(6.6Hz)。y向隔振效果稍差,并在2.344Hz和4Hz时出现振动传递率增大的现象,其原因在于y向与太阳帆板方向垂直,在振动过程中受到太阳帆板振动的影响较大,但其最大振动峰值为0.52,与激励峰值1.00比较仍有较大衰减,因此,所设计隔振器整体隔振效果良好。
[Abstract]:When the satellite is in orbit, because of its complex environment, it will cause the low frequency vibration of the flexible antenna when it is disturbed by the external light pressure, temperature, gravity and so on. At the same time, the eccentric wheel and attitude adjustment inside the satellite body will also cause low frequency vibration. In order to avoid the coupling of low frequency vibration between them, a low frequency vibration isolator with good performance should be designed to meet the requirements. Although metal spring vibration isolator has better low frequency vibration isolation characteristics, it can not suppress the resonance peak well because of its small damping. Although rubber vibration isolator has the characteristics of large damping hysteresis, its low frequency vibration isolation performance is poor. In this paper, a compound vibration isolator composed of metal rubber and spring is studied to solve the bidirectional low frequency vibration isolation problem between flexible nature and satellite body. Based on the mechanical model of metal rubber and spring, the relationship between deformation and diameter ratio of spring and the constitutive equation of metal rubber are obtained, and the structural parameters of the isolator are designed. Based on the software platform of Patran and Nastran, the three-dimensional model and finite element model of the metal rubber spring vibration isolator are established. The first 26 natural frequencies and the main vibration modes of the isolator are obtained by analyzing the various modes of the isolator. The feasibility of the isolator is verified by the time-domain response analysis of the vibration isolator excited by white noise. Then the multi-body three-dimensional model and dynamic model including satellite body, metal rubber spring isolator, flexible antenna and cable net, solar panel are established by using Patran software. Based on the MSC.Nastran software, the first 90 natural frequencies and the main modes of the whole star system are obtained. By applying the unit pulse excitation in three directions, the time-domain response of the top node of the flexible antenna and the frequency response of the whole satellite system are simulated and analyzed under the connection of the isolator and the rigid connection without the isolator. The vibration isolation rate of the top node of the flexible antenna in three directions is calculated. The results show that the isolator has a good isolation performance for the four resonance frequencies of 2.344Hz ~ 3.32Hz ~ 4Hz ~ 4Hz ~ (6. 6Hz). The vibration isolation effect of z direction is the best. Compared with rigid connection without isolator, the vibration transfer rate of z direction is reduced by 65% 86.53% (2.344Hz), 99.91% and 99.56% (3.32Hz), respectively. 85.12% (89.27%) (4Hz), 90.72% (93.17%) and 33.83% (6.6Hz). X), the vibrational transmission rate decreased 11.48% and 66.73% (2.344Hz), respectively. 66.880.99.41% (3.32Hz), 56.55% (66.47%) and 65.54% (4Hz), 79.29% (94.5555) and 94.07% (6.6Hz). Y) had a slightly worse effect on vibration isolation, The increase of vibration transfer rate occurs in 2.344Hz and 4Hz. The reason is that y direction is perpendicular to the solar panel direction, which is greatly affected by the solar panel vibration, but the maximum vibration peak value is 0.52. Compared with the peak value of excitation 1.00, the overall vibration isolation effect of the designed isolator is good.
【学位授予单位】：哈尔滨商业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V443.4;TB535.1

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