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Dai Y.,Academy of Armored force Engineering | Chong X.,Academy of Armored force Engineering | Huang J.-C.,China National Machinery Industry Corporation
Advanced Materials Research | Year: 2014

The higher order crack tip fields for an anti-plane crack in functionally graded piezoelectric materials (FGPMs) under mechanical and electrical loadings are studied. Different from previous analyses, all material properties of FGPMs are assumed to be linear functions of x parallel to the crack. The boundary conditions on crack surfaces are assumed to be the stress free and electrically impermeable. By using the eigen-expansion method, the problem is reduced to solving the system of ordinary differential equations. The higher order stress and electric displacement crack tip fields for FGPMs are obtained by solving the ordinary differential equations. © (2014) Trans Tech Publications, Switzerland. Source


Xie B.,China National Machinery Industry Corporation | Zhan W.,University of Chinese Academy of Sciences | Wang X.,University of Chinese Academy of Sciences
Applied Mechanics and Materials | Year: 2014

During the last ten years, the international construction market has kept growing. However, not all the international contractors have good performance according to the study of the rankings of international contractors in ENR TOP 225. The core competence analysis model was established according to the theory and research of the competitiveness in international contracting industry. Two methods to determine the core competences of leading international engineering constructor were confirmed. Firstly, the core competences could be found by studying the market performance to research companies' products, services and core business units. Secondly, the general competences and core competences could be determined according to the enterprises' resources and capabilities to determine. © (2014) Trans Tech Publications, Switzerland. Source


Chen Z.,China National Machinery Industry Corporation | Zhou L.,Chinese Academy of Agricultural Sciences | Zhao B.,Chinese Academy of Agricultural Sciences | Liang X.,Chinese Academy of Agricultural Sciences
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

The chassis frame is the installed base of the corn combine harvester, which bears a lot of force from the longitudinal bending, torsion, lateral bending, horizontal rhombic and their combined loads. The frame has obvious dynamic load characteristics, therefore the static strength check is not enough and research on the fatigue life is needed. As the lack of basic research, the key data accumulation is insufficient, the tradition design method is relatively limited, many Chinese products lack the necessary fatigue strength in design, and the reliability is poor. Experience in the automotive industry has proved that the combination of fatigue load spectrum and CAE technology can greatly improve the forecasting ability. Fatigue strength study of the corn combine harvester is the foundation of improving the reliability and an important method to reduce the structural mass. In order to reduce the structural weight and improve the fatigue reliability of the corn combine harvester, this paper studies a method to evaluate fatigue life of the main frame. Firstly, using ANSYS software, the stress distribution of the corn harvester chassis frame was analyzed, and the stress distribution of the maximum modal deformation position and under static stress analysis was obtained by the finite element analysis. The resonance was the biggest at 81.4 Hz frequency, so S8 point of the maximum strain region was placed on the frame to measure the strain. S5, S9 and S10 points were the high stress concentrated points and strain gauge needed to be placed. Other measuring point was placed on the part redesigned. Secondly, the stress data acquisition system was established, including sensors, data acquisition module and computer. Based on the modal analysis and static analysis, the strain gauge was pasted on the high stress concentrated points with the appropriate method, and the strain time histories of various typical conditions were measured through many experiments, which the operating speed of the corn harvester was the first and second gear in field operations, and the third in the road transport. Eventually, the stress and dynamic load characteristics were analyzed, the fatigue life of main frame was evaluated, and the lightweight design was completed by using nCode software. After the strain data acquisition, data preprocessing was carried out to ensure the evaluating accuracy, including the elimination of singular points, the elimination of temperature drift, noise filtering and so on. After eliminating the false data, the load spectrum was compiled by the rain flow method, and the load distribution curve of the load was obtained. Fatigue life of S-N curve was the cyclic number of fatigue crack under the condition of equal amplitude stress, and it could be considered as a superposition of different frequency and amplitude, so we used the principle of fatigue cumulative damage to evaluate the fatigue life. The result showed that, the fatigue life of the main frame was 241000 hours. The fatigue life on the road was longer than on the field, and the fatigue life was quite different at different measuring point. The main design part was an important supporting part connecting the body and rear axle. In the fatigue life analysis, it was found that the fatigue life of part was far greater than that of the body. Based on the fatigue life distribution, the optimization design of the main part in frame was completed. The result showed the new model can reduce 24% part mass under the condition of meeting the strength requirement. In this paper, the fatigue life of main frame was studied by combining fatigue load spectrum and CAE analysis, and lightweight designed was finished. This method can not only improve the stress distribution, strengthening rigidity, but also reduce the structural weight. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved. Source


Dai Y.,Academy of Armored force Engineering | Chong X.,Academy of Armored force Engineering | Huang J.C.,China National Machinery Industry Corporation
Manufacturing and Engineering Technology - Proceedings of the 2014 International Conference on Manufacturing and Engineering Technology, ICMET 2014 | Year: 2015

The higher order crack tip fields for anti-plane crack in Functionally Graded Piezoelectric Materials (FGPMs) under mechanical and electrical loadings are investigated. Different from previous analyses, all material properties of the functionally graded piezoelectric materials are assumed to be power function of x parallel to the crack. The boundary conditions on crack surfaces are assumed to be the stress free and electrically impermeable. Similar to the Williams’ solution of homogeneous elastic materials, the higher order crack tip fields of FGPMs are obtained by the eigen-expansion method. This study possesses fundamental significance as Williams’ solution to homogeneous materials. © 2015, Public Library of Science. All Rights Reserved. Source


Li J.,China Agricultural University | Chen Z.,China National Machinery Industry Corporation | Yang M.,China Agricultural University | Huang Y.,China Agricultural University
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2012

From a perspective of agricultural machinery and agronomy combination, a method was proposed to analyze corn production mechanization system. Based on the analysis of background and conditions, an analysis framework of corn production mechanization system was put forward, which was focusing on technology integration, organizational integration and management integration. For technology integration, the available agricultural and agronomic technologies those can be combined in the process of production mechanization were analyzed. For organizational integration, the existing categories of service organizations of corn planting and agricultural machinery were summarized to analyze the integration idea and method of the combination of agricultural and agronomic technologies. For management integration, suggestions on resource management, task adjustment and process management were proposed to promote the corn production mechanization. Source

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