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141.
阻尼陀螺系统动力响应的有限元复模态分析方法 总被引:2,自引:2,他引:0
采用复模态分析方法研究了陀螺系统及具有粘性阻尼的陀螺系统的动力响应及其数值分析方法,提出了陀螺模态阻尼比的概念,实现了利用有限元结构分析软件对诸如薄壁旋转轴和转动薄壁壳体等各类形式的复杂旋转薄壁结构进行动力特性分析的目的,讨论了不同条件(单点旋转简谐激励和沿圆周呈周波型分布的激励)条件下转动薄壁壳体结构的行波振动特点. 相似文献
142.
The gears in aero-engines perform energy and motion transfer between the HighPressure Rotor(HPR) and accessories. Firstly, an occurred fault with radial cracks in the driven gear disk was diagnosed as High Cycle Fatigue(HCF) failure through necessary examinations.Analysis of fault tree and test signals indicated that the fracture was relevant to the swing vibration of the driven gear excited by the unbalance excitation on HPR. Secondly, a corresponding mechanism model was established, in which t... 相似文献
143.
Installing winglets can notably improve the aerodynamic performance of solar aircraft.This paper proposes a multi-constraints optimization method of winglets for solar aircraft, aiming to enhance the corresponding uninterrupted cruising capability. An optimization objective function is formed and is separately studied in aerodynamic and structural terms. Qualitative analysis shows that the winglet design parameters are restricted by four special constraints(geometry, aerodynamics, energy and sta... 相似文献
144.
The pintle valve is currently the most promising technology among all thrust control methods for solid rocket motors. Pintle structure and working condition play a critical role in the successful operation of a pintle motor. Here, 2D transient simulations of a pintle motor using dynamic meshing are performed. Reynolds-averaged Navier–Stokes equations are solved with the implementation of an RNG k–e turbulence model. In cold flow test, emphasis is placed on the effect of pintle structure, and in ... 相似文献
145.
从Bernstein磁流体力学能量原理出发,讨论圆柱坐标下一类带奇异电流密度面的一维单参数无力磁场的稳定性.这类无力磁场在参数空间同时存在稳定区和不稳定区,其稳定性完全由磁螺距在圆柱轴邻域内的径向分布决定,与位于磁场边界处的奇异电流密度面无关. 相似文献
146.
Research progress on solid-fueled Scramjet 总被引:1,自引:0,他引:1
Xiang ZHAO Zhixun XIA Likun MA Chaolong LI Chuanbo FANG Benveniste NATAN Alon GANY 《中国航空学报》2022,35(1):398-415
The solid-fueled Scramjet is an interesting option for supersonic combustion ramjet. It shows significant advantages such as simple fuel supply and compactness, avoiding the complex system of tanks and pipelines that encountered in liquid-fueled Scramjets. The solid-fueled Scramjet could be the simplest air-breathing engine for the hypersonic flight regime. This paper presents a comprehensive and systematic review of the research progress on solid-fueled Scramjet in various institutes and univer... 相似文献
147.
Due to the strong background noise and the acquisition system noise, the useful characteristics are often difficult to be detected. To solve this problem, sparse coding captures a concise representation of the high-level features in the signal using the underlying structure of the signal. Recently, an Online Convolutional Sparse Coding(OCSC) denoising algorithm has been proposed. However, it does not consider the structural characteristics of the signal, the sparsity of each iteration is not eno... 相似文献
148.
Ao HE Honggang GAO Shanshan ZHANG Zhenghong GAO Bodi MA Lulu CHEN Wei DAI 《中国航空学报》2022,35(10):95-105
The Stopped-Rotor(SR) UAV combines the advantages of vertical take-off and landing of helicopter and high-speed cruise of fixed-wing aircraft. At the same time, it also has a unique aerodynamic layout, which leads to great differences in the control and aerodynamic characteristics of various flight modes, and brings great challenges to the flight dynamics modelling and control in full-mode flight. In this paper, the flight dynamics modelling and control method of SR UAV in full-mode flight is st... 相似文献
149.
The support given by Earth observation data and Earth system science play an increasingly important role in global change, regional sustainable development, extreme events, and the development of social and economic needs. This field is also moving towards systematization, platforms, and standardized development. In December 2015, nearly 200 parties of the United Nations Framework Convention on Climate Change agreed in Paris to make arrangements for global action in response to climate change by 2020. China jointly issued a climate change adaptation strategy for cities in 2016 and then elevated national action to respond to climate change. China's Earth Observation and Earth Science development is facing new challenges as it supports the national civil space infrastructure and high-resolution Earth observation system. 相似文献
150.