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971.
Topology Optimization Design for the Layout of theMain Bearing Joint of a Certain Aircraft 下载免费PDF全文
为了实现飞机部件的轻量化设计,将拓扑优化和代理模型相结合构建了一个结构布局优化的算法。以某型飞机主承力接头为研究对象,根据结构传力路线和工艺要求,将接头的布局优化转化为耳片的平面拓扑优化与螺栓位置的优化。以接头耳片的厚度和中间排螺栓位置作为布局变量,对每组布局变量下的耳片进行拓扑优化,对布局变量采用基于代理模型的遗传算法进行优化。以质量最小为优化目标,在强度与刚度的多约束条件下,完成了某型飞机主承力接头的布局拓扑优化。结果表明,本方法的优化结果比传统的拓扑优化结果减重约 14.5%,验证了优化算法的可行性与有效性。 相似文献
972.
973.
根据大型对日定向装置的结构特点和受力特性,调整传力结构,充分利用纤维增强复合材料结构的可设计性,开展优化设计。在保证高刚度和轻量化的同时,克服结构大开口带来的承载能力不足,设计出结构质量与承载比仅为5.2%,集舱段和壳体功能于一体的大型对日定向装置复合材料主承力架结构。建立有限元模型,分别采用Tsai-Wu和最大应变2种纤维增强复合材料的强度失效准则,对其进行校核。开展静力试验,采集应变等信息,与有限元仿真分析结果展开对比。结果表明:其整体趋势一致,顺利通过试验考核。 相似文献
974.
975.
针对高温环境下轴承材料性质和润滑状态变化,造成轴承磨损加剧,过早丧失精度的问题。首先开展高温环境下轴承用材料的摩擦磨损试验,获取材料的磨损系数。在此基础上,考虑温度、润滑、轴承材料属性等对轴承磨损性能的影响,建立高温角接触球轴承磨损模型,通过数值求解探讨工况参数和结构参数等对轴承磨损性能的影响,并评估轴承的磨损寿命。结果表明:对于高温轴承材料无磁合金GH05,在高温300 ℃摩擦状态下平均磨损系数为2.5×10-7 mm2/N;随着载荷、转速、温度的增加,轴承内、外滚道的磨损率均不断增大,其中内圈磨损率大于外圈,内圈磨损特性决定着轴承的磨损寿命;载荷和转速是决定轴承磨损寿命的主要因素,轴承主结构参数对磨损寿命具有重要影响,通过结构优化可提高轴承磨损寿命。 相似文献
976.
Aimed at the problem of store separation from internal cavity, this paper innovatively puts forward a separation scheme of using lateral jet to assist store safe separation. The jet ensures that the store is continuously subjected to down head moment during separation, so as to ensure safe separation. The wind tunnel free drop test technique with lateral jet is established, which can ensure that there is no support interference in the motion process of the store and more truly simulate the motio... 相似文献
977.
《中国航空学报》2023,36(5):157-174
The Secondary Air System (SAS) plays an important role in the safe operation and performance of aeroengines. The traditional 1D-3D coupling method loses information when used for secondary air systems, which affects the calculation accuracy. In this paper, a Cross-dimensional Data Transmission method (CDT) from 3D to 1D is proposed by introducing flow field uniformity into the data transmission. First, a uniformity index was established to quantify the flow field parameter distribution characteristics, and a uniformity index prediction model based on the locally weighted regression method (Lowess) was established to quickly obtain the flow field information. Then, an information selection criterion in 3D to 1D data transmission was established based on the Spearman rank correlation coefficient between the uniformity index and the accuracy of coupling calculation, and the calculation method was automatically determined according to the established criterion. Finally, a modified function was obtained by fitting the ratio of the 3D mass-average parameters to the analytical solution, which are then used to modify the selected parameters at the 1D-3D interface. Taking a typical disk cavity air system as an example, the results show that the calculation accuracy of the CDT method is greatly improved by a relative 53.88% compared with the traditional 1D-3D coupling method. Furthermore, the CDT method achieves a speedup of 2 to 3 orders of magnitude compared to the 3D calculation. 相似文献
978.
979.
《中国航空学报》2023,36(2):377-387
For designing efficient lubrication system of an aeroengine bearing chamber, sufficient knowledge on oil/air two-phase flow characteristics is required. When analyzing bearing chamber two-phase flow, the essential prerequisite is quantifying the oil ligaments, which are detached from bearing rotary elements and shed into the bearing chamber. Related investigations are mainly targeted at liquid shedding on the rotating disk as opposed to the bearing rotary elements. Moreover, the research based on bearing rotary elements is conducted by experiment. Due to the limited operating conditions, experimental studies cannot guide engineering applications. To overcome these limitations, a theoretical model is established in this paper, for revealing the mechanism of oil shedding from bearing rotary elements and quantifying the shedding ligaments. The theoretical model is validated against experimental results from classical studies. In addition, the correlation for shedding ligaments number based on aeroengine bearing structural and operational parameters is obtained via theoretical analysis. The analytical results demonstrate that oil shedding and ligaments formation appear at the edge of bearing inner race outer-periphery. The number of shedding ligaments increases with the rise of shaft rotational speed while decreases with the growth of oil viscosity. 相似文献
980.
Xingxing JIANG Qiang HUANG Changqing SHEN Qian WANG Kun XU Jie LIU Juanjuan SHI Zhongkui ZHU 《中国航空学报》2022,35(1):348-364
As critical components in modern aerospace productions, rolling element bearings(REBs) generally work under varying speed conditions, which brings great challenges to their operating health monitoring. Some novel time–frequency decomposition(TFD) algorithms are established recently to extract nonlinear features from the non-stationary signals effectively, which are promising for realizing fault diagnosis of REBs under varying speed conditions. However, numerous personal experiences must be incor... 相似文献