钛合金在航空航天领域中的应用探讨

近几年,我国不断增强空中军事力量的建设,加大对外太空的探索步伐,促使了一种新金属的快速发展,那就是钛合金的研发应用和推广。在航空航天的领域中,对其所需要的建设和组成材料有着严格的要求标准,往往要求这些材料具有较高的强度性、耐高温性和抗腐蚀性。文章对钛合金在航空航天领域的应用进行了探讨。

ANALYSIS FOR AIRCRAFT TAXIING AT VARIABLE VELOCITY ON UNEVENNESS RUNWAY BY THE POWER SPECTRAL DENSITY METHOD

In this paper a novel approach for the analysis of non stationary response of aircraft landing gear taxiing over an unevenness runway at variable velocity is explored, which is based on the power spectral density method. A concerned analytical landing gear model for simulating actual aircraft taxiing is formulated. The equivalent linearization results obtained by probabilistic method are inducted to treat landing gear non linear parameters such as shock absorber air spring force, hydraulic damping and Coulomb friction, tire stiffness and damping. The power spectral density for non stationary analysis is obtained via variable substitution and then Fourier transform. A representative response quantity, the overload of the aircraft gravity center, is analyzed. The frequency response function of the gravity overload is derived. The case study demonstrates that under the same reached velocity the root mean square of the gravity acceleration response from constant acceleration taxiing is smaller than that from constant velocity taxiing and the root mean square of the gravity acceleration response from lower acceleration taxiing is greater than that from higher acceleration.

民用航空的前景

本文所述未来的航空对于压倒一切的提高燃料使用效率的技术职责和机场拥挤状况将作出的反应,在很大程度上只是作者个人的评价,而不是国际民航组织的官方意见。但是,作者有作为飞机驾驶员、空中交通管理员和政府与国际民航的高级行政管理人员的长期和富有特色的经历,他“对未来广阔天地的冒险”(作者的语言)提供了一个令人感兴趣的方案。