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Zou Z.,Yanshan University | Guo B.,Yanshan University | Jin M.,Yanshan University | Mao C.,Taiyuan Heavy Industry Co.
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2016

The local high stresses appeared commonly in a loaded huge complex structure. Some of them were usually close to or even exceed the material yield strength due to the restrictions of the geometric size and the practical manufacture. It was troublesome with the applications of the conventional elastic strength design rule. The elastic-plastic shakedown design rule might utilize the plastic bearing capacity of material, then to solve this kind of strength problem well. Thus the shakedown theorem was introduced, and based on Melan shakedown theorem, a self-equilibrium stress field was constructed by subtractting the elastic-plastic stress field and the elastic reference stress field of the peak load, and the corresponding shakedown condition was derived. Then with the applications of the elastic-plastic incremental finite element technique, the loading-unloading calculations for different load levels were conducted to obtain the residual stress fields. Taking consideration of the relation between the residual stress field and the constructed self-equilibrium stress field, the shakedown limit load was determined by the shakedown conditions. Then a shakedown numerical analysis method for huge complex structure was established. The shakedown analysis for the main hydraulic cylinder of a 125 MN forging hydraulic press was performed by this new method. © 2016, CHINA MECHANICAL ENGINEERING Magazine Office. All right reserved. Source

Zhang C.,Education Institute of Taiyuan University | Zhang G.,Taiyuan Heavy Industry Co.
International Journal of Advancements in Computing Technology | Year: 2012

With the rapid growth of documents of the World Wide Web (WWW), how to effectively manage a huge amount of web pages has become the focus of contemporary research. Web page classification is one of the most effective methods for web mining. Many existing pure-text classification methods are simply applied to web page classification tasks. However, web page classification is much more difficult than pure text classification due to much contextual and structural information, e.g., the URL, the title, the anchor text, etc., embedded in Web pages. These heterogeneous data sources play different roles in the process of web page classification. In order to solve this problem, a novel web page classification method based on kernel combination is presented. Our aim is to propose an approach capable to automatically design a composite kernel which combined each single kernel of these heterogeneous data sources and to optimize its parameters by Quadratic Programming (QP). Experimental results on WebKB data set show that the proposed method can achieve much more superior performance than traditional methods based on each single data source and simple combination of them. Source

Li A.,Taiyuan Heavy Industry Co.
Applied Mechanics and Materials | Year: 2012

Solid-web double-beam component is widely used in the dipper handle of excavator, whose mechanical behaviour belongs to compression-bending member and mainly satisfies the strength requirement. In this paper, it starts from the design principles of steel structure and elastic theory, determines the dimension of the main cross-section and the reverse tube under guidance of optimization, and provides initial data for the detailed design. The method has common direct sense. © (2012) Trans Tech Publications, Switzerland. Source

Wang L.-W.,Taiyuan Heavy Industry Co.
Kongzhi Lilun Yu Yingyong/Control Theory and Applications | Year: 2013

The exact simulation model of the body and the main control system of a large fast forging hydraulic press is built by using the ITI-SimulationX software. The integrated simulation of the three-dimensional body and the onedimensional system is performed. The results show that fast forging hydraulic press can attain the forging precision of ±1 mm and the maximum forging frequency of 85 strokes/min during hot forging. For a large fast forging hydraulic press, which has wide process range and complicated operating conditions, we design the Takagi-Sugeno fuzzy controller which includes the forging stroke, forging penetration, maximum working pressure, working hydraulic cylinder number and the number of main pumps as input variables, and the open-close curve of the high-frequency-response proportional valve as output variable. Fuzzy reasoning rules are deduced from simulation results of the main control system by using MATLAB/ Simulink software. The intelligent control for the main control system is realized by using the co-simulation interface modules of ITI-SimulationX and MATLAB/Simulink, providing high forging precision and fast response speed under different technological parameters and accommodating to various process requirements for large fast forging hydraulic press. Source

Gui H.-L.,Taiyuan University of Science and Technology | Li Q.,Taiyuan Heavy Industry Co. | Huang Q.-X.,Taiyuan University of Science and Technology | Shen G.-X.,Yanshan University
Journal of Marine Science and Technology (Taiwan) | Year: 2013

This paper introduces a variable elements length theory to solve the change of contact area in contact problems. It avoids recalculating the whole coefficient matrix. In this theory, element length is changed instead of element number in contact boundary problem. This measure keeps the contact area unchanged and saves computing time. The iterative process is discussed and the error estimate is given. Fast multipole boundary element method (FM-BEM) is improved by the variable elements length theory. The improved FM-BEM is used to solve the contact problems of cubes and strip cold rolling process. The results of improved FM-BEM are compared with the results of traditional FM-BEM and experimental data. Numerical examples clearly demonstrate that the calculation time and accuracy are improved by the improved FM-BEM. This method is suitable for solving contact problems and precision engineering problems. Source

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