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Mao Y.,Beihang University | Kang R.,Beihang University | Ma L.,Beihang University | Xu Z.,AVIC Aerospace polytechnology Establishment
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2011

In order to achieve the integrality of the supportability analysis during the development phase of materiel, the determination method of corrective maintenance task items was presented based on the characteristics of failure mode, effects and criticality analysis(FMECA), the calculation of semantic similarity and the research of similarity for the units and systems. This method accounts for the bias of similarity calculation of units which is due to the unsurely level of unit's failure mode, and according to the similarity of units to complete the quantitative similarity calculation of system to assist the determination of corrective maintenance task items which depends on the similarity of different materiel. In addition, because of using the computer-aid, this method not only improves the effect and efficiency for the calculation process, but also somewhat avoids the differences between different supportability analyzers because of their own experiences and diversity. This method regulates the process of determination of corrective maintenance task items. The final example proves the method is effective.

Zhang Z.,Beihang University | Xu A.,AVIC Aerospace polytechnology Establishment | Li B.,Beihang University | Zhang X.,Beihang University
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2011

Rivet arrangements of joints determine the distributions of rivet loads, and then the fatigue lives of joints. Optimization of rivet arrangements of joints will efficiently elongate the fatigue lives of joints. Damage mechanics properly describes the coupling effects of stresses and damage and evolution of damage, by combining stress analysis of structures with damage analysis of materials. This methodology provides a powerful tool of fatigue analysis for engineering structures. Based on the theoretical method of damage mechanics, optimization of rivet arrangements of joints is discussed , under the guideline of "denser spacing of smaller rivets instead of sparser spacing of bigger rivets"(DSSB), and the fatigue lives of the resulting joints are evaluated in aid of finite element code. Those selected designs possess multiple outstanding advantages of stress level reduction, fatigue life extension, and weight minimization of joints comprehensively. Additionally, the damage mechanics method provides the theoretical instruction for joint design against fatigue, with limited experiments within much shorter design period, which can also be adopted as real-time monitor of structure damage evolution. © 2011 Journal of Mechanical Engineering.

Zhao N.,Beihang University | Zhao N.,China Shipbuilding Information Center | Zhao T.-D.,Beihang University | Feng C.,AVIC Aerospace polytechnology Establishment
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2014

The key point of dynamic reconfiguration system safety mechanism analysis is the system complex characteristics. The characteristics are reflected in the dynamic change of the functional subject. This change leads to difficulty in obtaining the dynamic reconfiguration system safety mechanism which is the system failure state evolution process leading the system to hazard. This paper first analyzes the multi-state-space problem caused by functional subject changing of the dynamic reconfiguration system. Then a hazard guided multi-failure analysis method is proposed based on the problem above. This method could help analyze the system safety mechanism, and obtain the development process of system failure state. At last, a study on a dynamic reconfiguration avionic system is conducted to illustrate this system safety mechanism analysis method.

Zhao F.,Beijing University of Posts and Telecommunications | Luo H.-Y.,CAS Institute of Computing Technology | Lin Q.,AVIC Aerospace polytechnology Establishment | Ma Y.,Beijing University of Posts and Telecommunications
Tongxin Xuebao/Journal on Communications | Year: 2010

To position indoor objects accurately and robustly, a novel node localization based on kernel function and Markov chains was presented, which employs Bayesian filter framework and radio fingerprinting technology. It uses kernel function to construct likelihood function to take full advantage of the similarity between observation and several training samples, which avoids the error brought by employing a priori determined distribution model. Furthermore, the proposed algorithm uses Markov chains to improve the localization accuracy and shorten the positioning time. It limits the search space of the matching grids with object's previous state and the environment layout, and refuses the object's impossible position jump during the moving process. Experiments confirm that the proposed localization outperforms the algorithm with Gaussian distribution model.

Zheng Z.-T.,Beihang University | You Y.-L.,Beihang University | Liu X.-L.,Aerospace Research Institute of Materials And Processing Technology | Zhang Z.,Beihang University | Lu H.-T.,AVIC Aerospace polytechnology Establishment
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2013

Based on the macroscopical propagation site area and microscopic fatigue striations of the fatigue fracture of titanium alloy joint with electron beam welding, fatigue stress and initial fatigue quality (IFQ) was estimated, respectively. The results show that the area of propagation zone can well estimate the stress at the same fracture toughness. And the relative error can be confined less than 10%. The microscopic characteristic of fatigue crack propagation at the second stage if fatigue striation. The IFQ estimated through Paris formula presents a normal distribution and the results have important engineering significance for the assessment of electron beam welded titanium alloy structure.

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