【作者】 徐强；

【导师】 漆文凯；

【作者基本信息】 南京航空航天大学 ， 航空宇航推进理论与工程， 2016， 硕士

【摘要】 在叶片中间叶根处设置减振阻尼器,可以较好地解决叶片振动过大问题,当叶片受到外部激振力作用产生振动时,阻尼器与缘板之间的往复干摩擦能够消耗振动能量从而起到减振作用,同时能降低振动应力。干摩擦阻尼具有减振效果好,有效工作裕度宽,恶劣条件下能够正常工作等特点,目前已广泛应用于航空发动机转子叶片的减振设计中。从多角度研究干摩擦阻尼的减振特性及其对叶片动力特性的影响,具有特别重要的理论意义和工程实际应用价值。本文建立叶根带缘板的叶片/盘有限元模型,应用一维整体-局部统一滑动干摩擦理论,对叶片承受准周期激励及叶盘扇区质量不均匀状态时缘板干摩擦阻尼器的减振特性进行仿真分析。最后,推导一种新型“Cottage Roof”阻尼片的接触界面干摩擦理论模型,考察该型阻尼片结构参数对其减振效果的影响。本文主要研究工作如下:(1)查阅相关资料,选定准周期激励形式作为激振源。建立叶片有限元模型,开发适用于计算准周期激励的时域计算程序,得到对应算例的频率响应曲线并总结干摩擦阻尼的减振规律。(2)建立更贴合工程实际结构的叶盘扇区模型,各个叶片之间通过刚度单元和阻尼单元进行耦合,通过线性化方法得到等效刚度和等效阻尼系数,研究叶盘扇区分别在缘板阻尼片质量不均匀及叶片质量不均匀两种状态时叶片的振动特性及干摩擦阻尼的减振特性。(3)建立“Cottage Roof”型阻尼片接触界面干摩擦理论模型,得到阻尼片摩擦力与位移本构表达式及不同屋顶角度时的迟滞回线,利用能量法和一阶谐波平衡法推导等效刚度和等效粘性阻尼公式,进而建立该型阻尼片的一维整体-局部统一滑动模型。(4)设计和制造不同屋顶角度和不同厚度的“Cottage Roof”型阻尼片,通过试验结果和仿真计算结果的对比,验证该型阻尼片干摩擦理论的正确性。开发振动响应计算程序,研究“Cottage Roof”型阻尼片屋顶角度、厚度、摩擦系数、准周期激励形式对其减振特性的影响。更多还原

【Abstract】 Platform damper is a kind of effective method to deal with a blade vibration problem caused by excitation force. Energy absorption by dry friction damping between the damper and the blade can play a role in reducing vibration amplitude and attribute to effective vibration stress reduction. Dry friction damping with good damping effect, effective working margin width, able to work under harsh conditions, etc. now has been widely used in the aero-engine rotor blades for the purpose of vibration reduction. Research from multiple perspectives on dry friction damping characteristics and its influence on the vibration characteristics of the blade has a particularly important theoretical significance and practical value in engineering.The main work of the paper is as follows:(1) Query the relevant documentation, choose a kind of quasi-periodic excitation as an oscillation. The blade finite element model is constructed, and based on which a time domain calculation program is developed. Then the frequency response curves of the corresponding numerical examples are obtained and the laws are summarized.(2) Establish a practical engineering structure finite element model of blade disc sector, and each blade on which is coupled by stiffness unit and damping unit. The corresponding equivalent coefficients are obtained by linearization method. The vibration characteristics of two states which have uneven quality of platform damper and blade are studied respectively and the damping characteristics are concluded.(3) Establish the dry friction theoretical model in the contact interface of a called “ Cottage Roof ” damper. The constitutive expressions about dry friction and displacement and hysteresis loops with different roof angle are obtained. The equivalent stiffness and equivalent viscous damping formula are derived by using energy method and the first-order harmonic balance method, thereby establishing the macro-micro slip model of this type of damper.(4) Design and manufacture the “ Cottage Roof ” damper with different roof angle and thickness. Do experiments to verify the validity of this type of damper sheet through the comparison between the experimental results and the simulation results. Develop the numerical calculation program, by which to investigate the dry friction damping characteristics about roof angle, damper sheet thickness, dry friction coefficient and different type of quasi-periodic excitation.更多还原