【作者】 林长亮；

【导师】 陈仁良；

【作者基本信息】 南京航空航天大学 ， 飞行器设计， 2012， 博士

【摘要】 鸟撞事故一般发生在600m以下的空域，而低空飞行是直升机的显著使用特点，因此直升机发生鸟撞的可能性很大，并且随着飞行速度的提高，鸟撞事故的危害性也在逐步加大。鸟撞轻则使机体损坏，重则会造成机毁人亡。旋翼是直升机非常重要的组成部分，一旦出现鸟撞损伤就会对直升机的飞行安全造成严重威胁，是抗鸟撞研究中需要着重解决的关键技术。我国民用直升机的抗鸟撞设计研究起步较晚，在民用直升机鸟撞方面开展的数值计算和鸟撞试验还很少。如何在设计的过程中采取有效的分析、设计和试验手段满足适航条例的要求已成为我国新型民用直升机研制中亟需解决的问题。本文详细地推导了鸟撞数值计算方法的理论公式，结合直升机旋翼鸟撞的特点，选择ALE流固耦合方法对某民用型直升机旋翼鸟撞进行了动态响应分析，并开展了相关的鸟撞试验研究工作。首先建立了某民用型直升机旋翼全尺寸鸟撞有限元模型。通过对旋翼固有特性的分析验证了旋翼有限元模型的有效性；桨叶材料的本构模型中考虑了应变率效应；以预应力的形式计入了离心力的影响。对撞击速度、撞击方向、撞击部位以及鸟体密度等鸟撞参数进行了桨叶动态响应影响性分析，得出了一些有参考价值的结论。针对桨叶后缘抗鸟撞能力薄弱方面，在不有悖于飞行器设计最小重量的原则下，提出了一些提高桨叶抗鸟撞性能的方法，并对这些方法进行了对比分析。设计制作了鸟撞试验装置，其中包括开炮机构、脱壳机构、鸟弹安装机构、明胶鸟弹等部件。利用该装置开展了鸽子鸟弹、明胶鸟弹撞击悬臂梁试验。在鸽子撞击试验中，并没有对鸽子进行宰杀；而是仅用保鲜膜将鸽子束缚住，直接发射出去撞击靶体，通过高速摄像结果可以看出，本文的方法更接近于真实的鸟体撞击。利用明胶鸟弹作为替代鸟体进行了撞击试验，发现明胶鸟弹能够很好地模拟鸟体在撞击过程中的流体动力学行为，为今后旋翼鸟撞试验中的替代鸟体研究奠定了一定的基础。由于直升机旋翼直径较大，并且在旋转过程中桨叶具有挥舞、摆振、扭转等运动，边界条件复杂，受试验条件和试验场地的限制，主桨叶全尺寸鸟撞试验很难实现。本文提出采用集中载荷作用下的桨叶静态鸟撞试验替代旋转状态下桨叶鸟撞试验，并利用数值计算方法验证了该方法的有效性，从而为直升机旋转部件的碰撞试验方法提供了理论依据。更多还原

【Abstract】 Bird impact usually occurs in the airspace below600meters. However, low altitude flying isthe most obvious characteristics of helicopter. Therefore, there is a great possibility that birdimpact occurs to helicopter. Moreover, with the improvement of flying speed, the danger of birdimpact is gradually deepening. Slight bird impact could cause plane body damage, while huge birdimpact could cause plane crash accident. The rotor is the most vital component of helicopter. Oncethe damage occurs, it will cause serious threat to helicopter’s flying safety which needs to beresolved urgently in anti-bird impact research.Anti-bird impact design research of civil helicopterin our country started fairly late and there are also few reports about numerical calculation andbird impact test related to civil bird impact. Therefore, How to meet AACA(Administration of theAirworthiness of Civil Aircraft’s) requirements in design process by adopting effective analysis,design and test means has become the problem that needs to be urgent resolved in thedevelepoment of our country’s new-style civil helicopter.In this paper, the numerical computation methods for bird impact were studied, and therelative theoretical formulas were derived. Combined with the characteristics of the helicopterrotor bird impact,The ALE fluid-structure method was adopted to analyze dynamic response ofone civil helicopter’s rotor bird impact and related bird impact test was carried out. Firstly, thefinite element model of one civil helicopter’s full-scale bird impact was established. Theeffectiveness of rotor finite element model was verified by analysing the inherent characteristics ofrotor blade. Strain rate effect was taken into consideration in blade material’s constitutive model,And the effect of centrifugal force was considered in the form of prestress. The influence of birdimpact parameters, such as impact speed, impact direction, impact part and bird density, on theblade’s dynamic response was analysed, and some conclusions which are of great reference valuewere reached.As for anti-bird impact’s weak aspect of blade trailing edge, some methods ofimproving blade anti-bird impact were proposed under the principle of minimum weight of aircraftdesign, and the contrastive analysis of those method was carried out.A bird impact test device was developed, which includes the fire mechanism, hullingmechanism, bird shot installation mechanism and gelatin birdshot. A test of pigeon and gelatinbird striking cantilever beam was carried out. In pigeon impact test, the pigeon was tied with clingfilm and directly launched to impact the target instead of being killed. The result from high speedcamera showed that the present method was even closer to real bird impact. Fluid dynamicbehavior in bird impact process was well simulated by gelatin birdshot. Thus, a certain foundation for bird replacement research in future’s blade bird impact test is built.The main rotor blade full-scale bird impact test is very hard to be realized due to thefollowing aspects: helicopter’s rotor diameter is larger; during rotating process, rotor consists ofdifferent motion forms such as flap, lag, torsion; boundary conditions are complicated; testcondition and test site are limited. In this paper,it was raised to adopt static bird impact withcentralized loads to replace that of rotating blade, and the effectiveness of this method was verifiedthrough numerical calculation method. Thus, theoretical basis is provided for impact test methodof helicopter’s rotating component.更多还原