约束阻尼结构扁簧动力学建模 及拓扑优化

	约束阻尼结构扁簧动力学建模及拓扑优化
其他题名	Dynamic modeling and topology optimization of constrained damping structure flat spring
	李兴光
学位类型	硕士
导师	贾宏光
	2015-11
学位授予单位	中国科学院大学
学位专业	机械制造及其自动化
关键词	扁簧结构阻尼粘性阻尼因子约束阻尼层拓扑优化
摘要	无人机在日常生活中有着越来越重要的应用。而无人机在起降过程中对起落架的要求较高，具有良好减振性能的起落架能提高飞机降落过程的稳定性。在各种起落架形式中，扁簧式起落架具有设计制造简单、成本低等优点，被广泛应用于小中型低速飞机中。由于提高扁簧的阻尼性能对飞机的平稳性具有重要影响，本文研究了扁簧阻尼模型的建立方法以及约束阻尼层的拓扑优化方法，为设计高阻尼性能扁簧提供了依据。主要研究内容包括： 1．根据扁簧单自由度自由振动试验数据分析了不同振幅下频率和粘性阻尼因子的变化趋势，并根据能量法建立了扁簧的动力学模型。最后将试验数据代入模型中进行计算，从而验证了结构阻尼计算方法的准确性。 2. 从能量的角度出发，依据模态应变能法推导约束阻尼层结构的动力学方程，通过粘弹性层和整体结构应变能之间的比值关系得到结构的模态损耗因子，用来表征扁簧结构阻尼的性能，为进一步拓扑优化提供目标参数。根据有限元方法推导了约束阻尼结构的动力学方程。 3. 建立约束阻尼板以横向位移w表示的振动微分方程，推导类悬臂结构在一端固支一端自由条件下的自由振动的解析表达式。以模态应变能法求得的前三阶模态损耗因子最大为优化目标推导出约束阻尼结构目标函数的灵敏度表达式。采用基于SIMP插值的优化准则方法对复合结构进行拓扑优化分析，以删除50%的粘弹性材料和对应的约束层材料为约束条件，使保留的材料对结构阻尼性能有较大的贡献率，从而实现对阻尼材料层的拓扑优化以减轻复合结构的总体重量。 4. 对拓扑优化结果进行试验验证，结果表明在删除一半的粘弹性材料和对应的约束层材料后，约束阻尼结构粘性阻尼因子变化量在5%以内。
其他摘要	The UAV is playing an increasingly important role in the modern life. The aircraft has a high demand for undercarriage while in the process of landing, and the undercarriage with good damping performance can improve the stability of aircraft landing process. Flat spring landing gear is one of the many layout forms which has many advantages, such as high reliability, simple structure, low cost and easy maintenance and mainly used in small and medium speed UAV. Because of the important influence on the stability of the aircraft by improving the damping performance of the flat spring, the paper studies the method of establishing the damping model and the topology optimization method of constrained damping layer. The main research contents include: According to the experimental data of the single freedom vibration of the flat spring, the changing trend of frequency and viscous damping factor under different amplitude is analyzed, and the dynamic model of the flat spring is established according to the energy method. Finally, calculate the test data into the model, which proves the correctness of structural damping model. From the energy point of view, the dynamic equations of constrained damping layer are established and the relationship between the modal loss factor and the strain energy is obtained according to the modal strain energy method. The modal loss factor is used to characterize the damping performance of the flat spring structure, which provides the target parameters for the topology optimization. The finite element dynamic analysis model of constrained damping structure is derived by finite element method. The dynamic analysis model of constrained damping structure is derived by finite element method. A differential equation of constrained damping plate vibration is established by horizontal displacement ‘w’, and an analytical expression of the natural frequency of the cantilever structure is derived from the theory in the condition of one end being fixed and another being freed. The sensitivity expression of the objective function of the constrained damping structure is derived by using the first three order modal loss factor, which is obtained by the modal strain energy method. The topology optimization of constrained damping structure is carried out by the optimization criterion method based on SIMP interpolation. The retained material has a greater contribution to the structural damping performance, by removing 50% of the viscoelastic and corresponding constrained layer material. In order to reduce the overall weight of the composite structure, the topology optimization of damping material layer is realized. The result of topology optimization is verified by experiments. The result shows that the change of viscous damping factor of constrained damping structure is less than 5% when the viscoelastic and corresponding constrained layer material is removed.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/49244
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	李兴光. 约束阻尼结构扁簧动力学建模及拓扑优化[D]. 中国科学院大学,2015.

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