Ding D.-W.,University of Science and Technology Beijing |
Li X.,University of Science and Technology Beijing |
Yin Y.,University of Science and Technology Beijing |
Xie X.-P.,The MCC Group
Information Sciences | Year: 2012
This paper investigates the stabilization problem of discrete-time two-dimension (2-D) Takagi-Sugeno (T-S) fuzzy systems. Based on a novel non-parallel distributed compensation (non-PDC) control scheme combined with a new non-quadratic Lyapunov function, less conservative stabilization conditions are developed. The proposed non-quadratic Lyapunov function is homogeneous polynomially parameter-dependent on membership functions. As the degree of the Lyapunov function increases, the conservatism of the obtained stabilization conditions is gradually reduced. By exploiting the algebraic property of membership functions, the stabilization conditions approach to exactness in the sense of convergence. Compared with the existing methods, no slack variables are introduced in control synthesis, and hence the same or less conservative results can be obtained with a lower computational cost. A numerical example is given to illustrate the effectiveness of the proposed method. © 2011 Elsevier Inc. All rights reserved.
Zhang C.,Taiyuan University of Technology |
Chen L.,Beijing Forestry University |
Jiang J.,Taiyuan University of Technology |
Zhou S.,The MCC Group
Trees - Structure and Function | Year: 2012
Root tensile strength plays an important role in soil stabilization and fixation. Testing and separating the different factors that affect root tensile strength are important. In the present study, the effects of four factors, namely, gauge length, strain rate, species, and root diameter, on root tensile strength were studied. Uniaxial tensile tests were conducted to acquire the root tensile strength of five tree species commonly growing in the mountains of northern China, namely, Chinese pine (Pinus tabulaeformis Carr.), Larch (Larix principis-rupprechtii Mayr.), White birch (Betula platyphylla Suk.), Mongolian oak (Quercus mongolicus Fisch.), and Elm (Ulmus pumila L.). Based on the results, Elm and White birch roots were the most resistant to tension, followed by Mongolian oak and Chinese pine roots. Larch roots were found to be the least resistant to tension. A power relationship was established between root diameter and root tensile strength. Based on linear regression analysis, gauge length was negatively correlated with root tensile strength. Tensile strength decreased with increasing gauge length. In addition, an unexpected variation of tensile strength was observed between two strain rates (10 and 400 mm min -1). The present study can serve as a basis for further studies on mechanical properties of root system and root reinforcement under different test circumstances, although this should be done with caution. © 2012 Springer-Verlag.
Yang X.,University of Science and Technology Beijing |
Tong C.,University of Science and Technology Beijing |
Meng J.,The MCC Group
Zhendong Ceshi Yu Zhenduan/Journal of Vibration, Measurement and Diagnosis | Year: 2010
By analyzing the vibration process of cold rollilng and using the structure mdel of rolling system, a rolling force mathematical model was built. In the model, the following factors are considered: roll and strip elastic deformation, strip height, rolling tension, the length of contact arc, frictional state, rolling speed and so on. After substituting the force model into the vertical and torsional vibration equations of motion of the rolling mill, a coupled set of equations is obtained, and the stability of the equations is analyzed by using the Routh criterion. By use of simuation, the model is confirmed, and the influence of different working conditions and the coupling between vertical and torsional vibrations on the stability of the vertical system of the mill is discussed, which builds up a foundation for further study of the coupled vibration of rolling mills.
Zou D.-F.,The MCC Group
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2013
Based on the comparison and analysis of the static load tests on the experimental ultra-long bored piles of CCTV Tower and World Trade Center Tower (third stage) in Beijing, the behaviors of the pile tip resistance and the shaft resistance are studied. The results show that the deformation of pile top is mainly from its compression under loads. The tip resistance makes minor contribution to the bearing capacity relative to the shaft resistance. The pile shaft resistance exhibits a softening phenomenon in clay layer and a hardening phenomenon in sandy soil layer, and its play exhibits depth effect. The bearing capacity distribution of piles estimated according to the specifications is greatly different from the test results. Both the effective cleaning residue process and the post grouting means are proposed to be necessary measures for the ultra-long bored piles.
Li M.,The MCC Group |
Xin H.-B.,The MCC Group
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2015
The seismic stability of earth-fill hill is one of the key problems in the process of design and construction, and has not been understood properly. The seismic permanent displacement of earth-fill hill is studied by means of the equivalent linear method and Newmark sliding block analysis. The influences of heights, average gradients and input ground motions on permanent displacement are investigated. When the slope is gentle, there are significant differences in size and sliding surface between the maximum displacement sliding mass and the most dangerous sliding block discriminated by the pseudo-static Bishop's method. Finally, using the yield acceleration of earth-fill hill, a simple method to estimate the seismic permanent displacement of earth-fill hill is proposed. © 2015, Chinese Society of Civil Engineering. All right reserved.