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Li H.,Northeastern University China | Wang X.,Northeastern University China | Yu T.,Northeastern University China | Su P.,Northern Heavy Industries Group | Wang W.,Northeastern University China
Qinghua Daxue Xuebao/Journal of Tsinghua University

Complex structure metal work-pieces, especially bionic porous structures in tissue engineering, can be manufactured with high shape precisions and efficiencies using laser direct depositing technology. Three-dimensional modeling, finite unit analyses of thermo field, and tissue growing technology were applied to metal selected laser sintering (SLS) to solve the problem of forming quality difference and nucleation discrepancy. The thermo field was simulated and analyzed using finite element method, with correlative affection of technical parameters then discussed. According to the thermo field analyses, metal nucleation growing process was provided by using the cellular automaton model based on the coupling finite element method and the growing mechanism, where the nucleation could be optimized by adjusting the correlated technical parameters. Based on the analytical results, the optimization and control of nucleation were realized by combining the macro model of thermo field analyses and the micro model of cellular automation. The simulation results are almost the same as those of the correlated experiments at a consistency level of 95%. Source

Lu F.,HIGH-TECH | Zhang C.,Shenyang Jianzhu University | Sun J.,Shenyang Jianzhu University | Tian J.X.,Shenyang Jianzhu University | And 2 more authors.
International Journal of Engineering Research in Africa

In order to improve working efficiency of the tunneling process and extend working life of disc cutter, explore the impact of cutter spacing and loading for the cutter rock-breaking effect. With the theory of rock crushing, Based on the finite element analysis software ABAQUS, the process of disc cutter breaking rock is simulated, considering the adjacent cutters sequential constraints, then, to make sure two cutter space with the method of SE in experiment.The simulation results showed that the optimal cutter spacings were both about 80mm in the same loading and the sequentially loading, but the rock-breaking effect of sequentially loading is better than the same loading. The experimental data showed that the minimum specific energy of rock breaking is appeared cutter spacing between 80mm and 90mm. Thus, the correctness and rationality of the simulation was verified. The study is good for understanding the rock-breaking mechanism of double disc cutter and has a certain promoting value to optimize TBM cutter system. © 2016 Trans Tech Publications, Switzerland. Source

Lin G.,Northeastern University China | Li W.,Northern Heavy Industries Group
Advanced Materials Research

The jib is an important component for the tower crane. The reliability of the tower crane jib has a direct impact on the safety production. In the current crane industry, the traditional allowable stress method is still the main method for designing tower crane jib. As a result, the reliability of the tower crane jib cannot be given quantitatively. In this paper, by using the probabilistic method, the reliability of a tower crane jib is worked out, and a design way based on the reliability for the tower crane jib is provided. © (2010) Trans Tech Publications. Source

Duan Y.,Shenyang University of Technology | Cui B.,Shenyang University of Technology | Xu B.,Northern Heavy Industries Group | Qu X.,Northern Heavy Industries Group
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering

In order to solve the problem that the material level detection of double-in double-out coal mill is difficult to implement under the whole operating condition. A material level detection method based on multi-sensor fusion is proposed. The fusion system is realized by rough sets and fuzzy neural network. According to the working characteristics of double-in double-out coal mill, the operating process is divided into three stages. The rough set theory is used to analyze the importance of each sensor to fusion and the confidence of decision rule in the different stages. Then fuzzy neural network is formed on the basis of the analysis results and used to implement the mapping from the multi-sensor information to material level. Furthermore, the attribute importance and rule confidence are introduced into the learning processes of fuzzy neural network. Experiment results show that the presented method is effective and it can perform precise material level detection. © 2010 Journal of Mechanical Engineering. Source

Li H.,Northeastern University China | Zhang B.,Northern Heavy Industries Group | Zhao H.,Northern Heavy Industries Group | Wang W.,Northeastern University China
Qinghua Daxue Xuebao/Journal of Tsinghua University

Rapid forming technology is more and more widely used in tissue scaffold and drug feeding systems. In this paper, 3-D modeling size compensation technology was used to reduce rapid forming tolerance and solve the problem of tolerance inconsistency with respect to repeatable manufacturing technology. The typical experimental work-piece was designed and was made by using an ultraviolet curing machine. The work-piece contains different kinds of size characters in three directions of X, Y, and Z. These character sizes were measured with the factors affecting forming accuracies synthetically analyzed. The results show that the 3-D modeling size compensation technology can effectively control forming accuracies, with the tolerance consistency being increased to 90% and above. Source

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