飞机结构弹性对起落架缓冲性能的影响

研究了飞机结构弹性对起落架缓冲性能的影响。建立了计及飞机结构弹性效应的起落架缓冲系统的动力模型和分析方法。应用结果表明,飞机结构弹性效应能降低起落架缓冲系统的过载、位移等,尤其对大、中型飞机主起落架更为明显,如,某Ｙ机主起落架过载降低６％。     

CTD调速电动机涡流场的有限元计算

本文用有限元方法对CTD调速电动机的涡流场进行了分析和计算。通过涡流损耗方法对CTD调速电动机的杯转子电阻进行了较准确地计算,为CTD调速电动机的研制设计提供了依据。最后通过试验电机杯转子电阻的测试和计算,得到了令人满意的结果。     

超声喷丸强化搅拌摩擦焊接接头性能

采用超声喷丸焊后处理工艺分别对7075-T651铝合金母材及搅拌摩擦焊焊接接头进行了处理,并与其原始状态进行了疲劳对比试验。对比疲劳性能试验结果证明该处理技术可用于提高7075-T651铝合金母材及搅拌摩擦焊焊接焊接接头试件的疲劳性能。     

考虑机体弹性的起落架着陆仿真分析

首先建立机身的有限元模型,该模型的模态与全机地面共振(GVT)试验测得模态相吻合.然后分析起落架缓冲器受力,并编制程序,计算出相关的曲线,LMS仿真平台调用上述曲线对单个起落架进行仿真,在单个起落架仿真结果与落震试验结果吻合的基础上,对某型飞机进行刚性机身全机落震仿真分析.最后调用机身有限元模型进行柔性机身全机落震仿真...     

航空机轮及刹车装置研制进展

简要综述了我国研制航空机轮及刹车装置的发展过程,着重叙述了国内外航空机轮及刹车装置当前的研究动态,对其发展动向也作了一些探讨.     

Parallel algorithm and its convergence of spatial domain decomposition of discrete ordinates method for solving radiation heat transfer problem

To improve the computational efficiency and hold calculation accuracy at the same time,we study the parallel computation for radiation heat transfer. In this paper, the discrete ordinates method(DOM) and the spatial domain decomposition parallelization(DDP) are combined by message passing interface(MPI) language. The DDP–DOM computation of the radiation heat transfer within the rectangular furnace is described. When the result of DDP–DOM along one-dimensional direction is compared with that along multi-dimensional directions, it is found that the result of the latter one has higher precision without considering the medium scattering. Meanwhile, an in-depth study of the convergence of DDP–DOM for radiation heat transfer is made. Analyzing the cause of the weak convergence, we relate the total number of iteration steps when the convergence is obtained to the number of sub-domains. When we decompose the spatial domain along one-,two- and three-dimensional directions, different linear relationships between the number of total iteration steps and the number of sub-domains will be possessed separately, then several equations are developed to show the relationships. Using the equations, some phenomena in DDP–DOM can be made clear easily. At the same time, the correctness of the equations is verified.     

Lick Observatory Optical SETI: targeted search and new directions

Lick Observatory's Optical SETI (search for extraterrestrial intelligence) program has been in regular operation for 4.5 years. We have observed 4,605 stars of spectral types F-M within 200 light-years of Earth. Occasionally, we have appended objects of special interest, such as stars with known planetary systems. We have observed 14 candidate signals ("triple coincidences"), all but one of which are explained by transient local difficulties. Additional observations of the remaining candidate have failed to confirm arriving pulse events. We now plan to proceed in a more economical manner by operating in an unattended drift scan mode. Between operational and equipment modifications, efficiency will more than double.     

雅江峡谷里飘出的悠远牧歌

如黛的森林包围着绒毯一般的草地，散落其中的牛羊，随处可见的玛尼堆和褪色的五彩经幡……初看雅江，似乎与川西高原的任一处别无二致。然而细细深入，在雅砻江以东的祝桑乡地区，小木窗上绘着美丽图案的石头民居，温软动听的语言，以及悠扬雅致的锅庄……一切都体现出古老神秘的木雅文化所特有的母性亲近感；而以西160多公里的西俄洛乡却处处牧歌豪放，一派典型的康巴画卷。只要你探身而入，雅江的自然与人文之美自会让你沉醉。     

雅江峡谷里飘出的悠远牧歌

如黛的森林包围着绒毯一般的草地,散落其中的牛羊,随处可见的玛尼堆和褪色的五彩经幡……初看雅江,似乎与川西高原的任一处别无二致。然而细细深入,在雅砻江以东的祝桑乡地区,小木窗上绘着美丽图案的石头民居,温软动听的语言,以及悠扬雅致的锅庄……一切都体现出古老神秘的木雅文化所特有的母性亲近感;而以西160多公里的西俄洛乡却处处牧歌豪放,一派典型的康巴画卷。只要你探身而入,雅江的自然与人文之美自会让你沉醉。