Hai Cheng Yang

The Detection of Avalanche Propagation in Engineering Change

In order to avoid avalanche propagation in engineering change that is high-risk and high-cost, two methods for the detection of avalanche propagation were proposed. Firstly, analyzed the reasons for the avalanche propagation and its main features: constraint conflict and/or a great many affected elements. Then, the methods for the detection of those two features based on directed graph and complex networks respectively were proposed. Finally, the experiment of managing a type of transmission was employed to validate our method and it showed the correctness of the proposed method.

Research on Multi Agent Data Acquisition and Processing Technology of Distributed Network

In this paper, it proposed the function structure of distributed network data acquisition and processing system; based on the analysis of Agent, Agent principle and functional module, according to the characteristic of the servo control system fault diagnosis which is the electro-hydraulic position of the electrical and mechanical equipment, it puts a data acquisition and diagnosis system of Agent network structure, the specific function of the dynamic monitoring control Agent and fault identification Agent, it establishes their models and discusses the multi Agent coordination mechanism, the task decomposition and the control strategy of fault diagnosis.

Multi-Dimensional Comprehensive Link Stability Model in Ad Hoc Network

Routing Optimization is always a key issue in MANET (Mobile Ad-Hoc Network). When referring to multi-media communication, the routing stability, which is up to link stability, is in urgent need. On the analysis of kinds of factors that affect link stability greatly, a multi-dimensional comprehensive evaluation model (MVCLS) was presented based on factor classification. In the model, the weight levels were classified, a mechanism of weight rotation was available, and a normalized link stability evaluation system with multi-attribute and multi-weight was formed. In addition, aiming at reliability and robust of the model, time series analysis and Kalman filter were combined to smooth and predict the value of key factors. At last, the link stability model is used to optimize the OLSR routing protocol, which takes the link stability as the important stuff for path selection. Simulation experiments of modified OLSR were done with support of Qualnet, the results of which show that the network performance is improved and also prove the effectiveness of the link stability model.

Quantitative and Meticulous Methods to Aero-Engine Assembly Process

Manual operation and paper document based management are the bottleneck to the quality and efficiency of aero-engine assembly process. A set of optimization methods is presented about the aero-engine assembly process. From the technical point, the model of LoA (Level of Automation) was expanded with the addition of the role dimension and task dimension to construct a quantified method of level of assembly information automation, which was utilized to guide the digitalization of assembly process. From the management point, the meticulous management was utilized to improve the microcosmic operation and macro flow control of assembly. A refine and quantified assembly digital system for aero-engine has been developed to verify the effectiveness of the optimization methods.

Research on Conjugate Heat Transfer in Mechanical Seals of the Aircraft Engine

According to the mechanical seals’ characters of the aircraft engine: no special flush fluid equipment and the limited space etc, a numerical model of conjugate heat transfer between seal rings and seal chamber is presented. And the flow channel and the flow quantity in the mechanical seal are studied, which will affect the heat transfer between the surface of the seal ring and the flush fluid. At last, the studied results are validated by the test.

Research on Aerospace Equipment Machining Process Optimization Based on MBD Procedure Model

The development of intelligent design manufacturing based on the three dimensional environment of knowledge engineering is the important research content. This paper set MBD procedure model as a process of design and the basic of optimization, establishing basic process said and evaluation method according to space product manufacturing characteristic. With Model based definition, the key equipment information of aerospace products manufacturing is the starting data of the process of optimization, and realize the space cable equipment a process design and optimization process, product process for space design and optimization provided based on full 3D model of application methods, established the process design of the application, the actual proof, design and optimization combined with MBD procedure model is the important guarantee of process design.

The Application of Visualization Technology in Advancement Degree of Difficulty Computing Process

In order to avoid the subjectivity and limitation of advancement degree of difficulty evaluating method based on lists, a visualizing method which applies the visualization technology in advancement degree of difficulty computing process is proposed. This method takes the improved technology readiness level assessing result of the technology to be assessed as the input of the visualizing process, and visualizes the readiness status of the technology to a two-dimension coordinate graph. The area which denotes the advancement degree of difficulty of the technology developing from one readiness level to a higher readiness level is shown in the coordinate graph. A computing formula is established to get the advancement degree of difficulty of the technology. The experimental results show that the proposed visualizing method can get the difficulty degree of the technology developing from one readiness level to another readiness level objectively and accurately.

Research of Multi-Attribute Group Decision Making for Aviation Manufacturing Enterprise Material Supplier

With more and more applications of manufacturing resource in networked manufacturing, material supplier evaluation and selection will become increasingly important. In the paper, the evaluation architecture of material supplier selection is introduced. Then, material supplier group decision making model is discussed. Lastly, multi-attribute group decision making for aviation manufacturing enterprise material supplier is verified based on fuzzy comprehension assessment by an illustration.

The Process DNA Model of Significant Model Project

To solve the problem of “two command line” existing in the significant model project management at present, this paper proposes a method of process DNA-based process management for significant model project. First, the technology process and management process of significant model project are analyzed. Second, the process DNA double-strand of significant model project is constructed employing the elements of technology and management as building blocks; and also, the two-level structure of the process DNA double-strand is analyzed. Third, the process DNA model of significant model project is established and the related formal definitions are given.

Study on the Processing Technology of ERTI-7 Titanium Wire Based on AHP-PQ Model

This article determines the main factors influencing the quality of ERTi-7 titanium wire through building AHP-PQ model: processing technology. under the circumstance of instable quality of ERTi-7 titanium wire in international market. Through the selection of raw material, feeding material evenly during melting, control of melting times and the determination of surface machining process, the inhomogeneity of chemical compositions of ERTi-7 and the corresponding removal method are studied. The results show that it is easier to obtain ingot with good surface and fine structure using triple melting without increasing the content of Pd element, and then going through non-oxidation roller-die drawing process, we will obtain qualified titanium wire with good surface and also conforming to the request of AWS A5.16/A5.16M:2007.