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Beijing, China

Wei Z.-H.,Beijing Jiaotong University | Wei Z.-H.,Logistics Command Academy | Wang M.-S.,Beijing Jiaotong University | Zhang D.-L.,Beijing Jiaotong University
Gongcheng Lixue/Engineering Mechanics | Year: 2012

The structural soil strength has always been an important issue in the soil and rock research. The soil and rock is structurally complicated, with a particle chain structure formed by the interconnection of soil particles as one of the dominant morphologies. The analysis for the formation conditions of the particle chain structure of a general type and a friction type is made through building a soil particle chain model, which is used to obtain the conditions for the friction-type particle chain to become stable. On this basis, we attempt to work out soil strength theory for a stable particle chain. It is found from the analysis that the conditions for friction-type soil particles to form a stable chain are related to the fabric relationship of particle composition and also to particle morphology; the strength of a particle chain can influence the soil macro-strength; the length, density and directional distribution of stable particle chains in the soil are important factors for soil strength and also important parameters to characterize the above-mentioned soil structure. The nature of friction-type particle materials to withstand the load is revealed from a particular perspective based on this soil strength theory for a stable particle chain. Source


Zhang K.-L.,National University of Defense Technology | Liu X.-L.,Logistics Command Academy | Guo B.,National University of Defense Technology
Jisuanji Jicheng Zhizao Xitong/Computer Integrated Manufacturing Systems, CIMS | Year: 2011

To estimate the product design time more precisely, the modeling methodology of Gaussian process meta-model was applied to estimate the product design time. The modeling principles of Gaussian process meta-model were firstly introduced. Since there were linguistic variables among the factors effecting product design time, Hausdorff distance was applied to assist the construction of relevant matrix in Gaussian Process modeling. The example analysis illustrated that Gaussian Process meta-model was superior to the existing two fuzzy neural network models. Source


Wei Z.-H.,Beijing Jiaotong University | Wei Z.-H.,Logistics Command Academy | Wang M.-S.,Beijing Jiaotong University | Zhang D.-L.,Beijing Jiaotong University
Yantu Lixue/Rock and Soil Mechanics | Year: 2012

The fractal structure is a common phenomenon of soil. Through analyzing influence domain(Voronoi domain) of the fractal structure connection point, the bearing capacity of particle connection is converted to stress intensity. Some beneficial results are obtained. Values of fractal dimension of particle system structure influence soil strength obviously. The particle of basic unit is more, the ring from the particle is longer, the space for the ring is larger; it is more instable in mechanical property, the strength is lower. The stage number of fractal structure determines the size of the maximum pore. The stage number of fractal structure is more, the size of the maximum pore is larger, the equivalent stress intensity is lower. The couple stress intensity is inversely proportional to the area of basic structure unit (two-dimensional). That is to say, the basic structure unit is larger, the couple stress intensity is lower. Therefore, it can be concluded that the particle is larger, the couple stress intensity is lower when other conditions are same. Source


Liu X.-L.,Logistics Command Academy | Liu X.-L.,National University of Defense Technology | Zhang K.-L.,National University of Defense Technology | Guo B.,National University of Defense Technology
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2010

For solving the problem of long calculation time when high accuracy simulation model was used in MDO analysis in complex systems, Gaussian Process Surrogate mode was proposed. Gaussian Process surrogate model theory was proposed, and its flow chart was analyzed in detail. Through example analysis, Gaussian Process surrogate model was proven better than anther two existing surrogate models. It shows that local surrogate models are special cases of Gaussian Process Surrogate mode, which will be the focus of investigation. Source


Wei Z.-H.,Beijing Jiaotong University | Wei Z.-H.,Logistics Command Academy | Wang M.-S.,Beijing Jiaotong University | Zhang D.-L.,Beijing Jiaotong University
Yantu Lixue/Rock and Soil Mechanics | Year: 2013

Many scholars have performed a large amount of researches on soil strength with considerable achievements. But the influence of soil structure on its strength has always been the difficult point. A soil structure strength model is established based on soil particle connection. From the analysis of this soil structure model established, it is found that the strength of soil mass is directly associated with the connection strength among particles and the distribution pattern of connections. When the stress-strength curve family in statistical domains is used to macroscopically analyze the soil mass properties, the yield surface composed of several curved surfaces can be gained. The analysis of examples of simplified soil structure morphology indicates that an isotropic stress-strength model can be obtained when the connection in each direction is evenly distributed. In addition, when the spatial characteristics of statistical domains are considered, for different local coordinates of macroscopic stress in the statistical domain, the stress gradient may influence the soil strength. This is exactly what the classical theories can not explain. Therefore, the strength model of soil structure being established is a kind of new and effective analysis method for structural soil. Source

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