Papers by Author: Gang Yang

Abstract: The porous ceramic biologic films were prepared on the surface of Ti6Al4V (TC4) with micro-arc oxidation technology (MAO). The phase composition, microstructure and valence state of micro-arc oxide films were studied. The biological properties of the ceramic film were comprehensive evaluated through animal experiments. Results show that with increasing of the micro-arc oxidation voltage, the better biocompatible hydroxyapatite appears on the surface of titanium alloy (TC4). The high voltage promotes the surface pore size enlarge. The porous ceramic surface makes bone tissue early grow up. Pathological sections of bone tissue 24 w animal experiments indicates that the implants can form good biological combination with bone, no rejection and the higher the micro-arc oxidation voltage, the more new bone cells.

Abstract: In this paper, based on the theory of ship-bridge collision, large-scale finite element software ANSYS is adopted to establish the calculation model of the bridge.According to the specification of our country, the calculation of bridge collision force then compares with the actual situation.Through the calculation of collision force, the ship-bridge collision is transformed into the problem of transient analysis of collision point.This article is mainly to analyze the change of bridge energy and the stress and displacement of main parts of the bridge. Finally, this article puts forward the personal vision.

Abstract: Steel single rib box section arch bridge is established on the basis of secondary development using parametric language of large-scale finite element software ANSYS. On the premise of same sectional area A of arch rib,height breadth ratio h/b is changed, and both the spatial instability mode under the condition of arch bridges dead weight and the stability safety coefficient under the condition of the first step instability mode is calculated. With the aim to optimize distribution of stiffness and stability of single rib arch bridge, the target is to find out a height breadth ratio h/b which can make in-plane and out-plane instability mode coupling, that is to say, equivalent stiffness of in-plane and out-plane of the mode.

Abstract: In order to study the behavior of piled wharf system under seismic excitation, numerical analyses are conducted by employing the Newmark’s time-integration algorithm. In the computational model, both nonlinearity of subsoil and the contact behavior between pile-soil interfaces are considered. The numerical results show that the horizontal displacement extremum of all piles in time history increase with the pile height under horizontal seismic excitation. Especially, the side pile of wharf system in the bank slope appears larger horizontal displacement compared with the other piles. Furthermore, the extremum variation of horizontal acceleration and bending moment of the side pile displays a non-monotonic characteristic. Based on computational results and theoretical analyses, several conclusion remarks are drawn, which can provide valuable and referable experience to some extent for related engineering practice and design.

Abstract: Based on Ježek method of computing the elastic-plastic buckling of the member under the axial compressive load and the bending moment, considering the initial imperfection, the analytical expressions of calculating the ultimate load of buckling about the neutral axis with the maximum moment of inertia for an H-shaped member are derived. Using the elastic-plastic finite element method and the theory of nonlinear buckling, the impact by initial geometric imperfections on the H-shaped steel member under the axial compressive load and the bending moment are analyzed and the numerical solutions of ultimate bearing capacity are obtained. By compared with the values of the finite element method (FEM), it shows that the analytical method in this paper is valid. The results of the example show that the presence of initial imperfections reduces the ultimate bearing capacity of the steel member to a great extent. It is also found that the influence of the initial geometric imperfection on the ultimate bearing capacity of member is smaller when the bending moment increases.

Abstract: Based on Ježek method of computing the elastic-plastic buckling of the member under the axial compressive load and the bending moment, considering the initial geometric imperfection, the analytical expressions of calculating the ultimate load of buckling about the neutral axis with the maximum moment of inertia for an H-shaped member with flange outsides wrapped by carbon fibre are derived. Using the elastic-plastic finite element method and the theory of nonlinear buckling, the impact of the initial geometric imperfection on the H-shaped steel member wrapped by carbon fibre under the axial compressive load and the bending moment are analyzed and the numerical solutions of ultimate bearing capacity are obtained. By compared with the values of the finite element method (FEM), it shows that the analytical method in this paper is valid. Compared the reinforced effect of the carbon fibrer to the perfection member with the defect member, we find that the former is higher than the latter. The results of the example also show that the presence of initial geometric imperfection reduces the ultimate bearing capacity of the steel member to a great extent. The influence of defect member gradually decreases when the given moment rises.

Abstract: The research of optimization for steel truss bridge based on reliability theory is discussed by using optimization and reliability module in ANSYS software. The reliability design method is elucidated by comparing the results of common design with general optimization and reliability optimization.

Abstract: Based on Ježek method of computing the elastic-plastic buckling of the member under the axial compressive load and the bending moment, the analytical expressions of calculating the ultimate load of buckling about the neutral axis with the moment of inertia for a square steel tube column are derived. By degenerated into the analytical expressions of the rectangular column and compared with the values of the finite element analysis (FEA) method, it shows that the analytical method in this paper is valid, which provides a new method of theoretical study for the elastic-plastic buckling of the member.

Abstract: Based on Ježek method of computing the elastic-plastic buckling of the member under the axial compressive load and the bending moment, the analytical expressions of calculating the ultimate load of buckling about the neutral axis with the maximum moment of inertia for an H-shaped column are derived. By degenerated into the analytical expressions of the rectangular column and compared with the values of the finite element analysis (FEA) method, it shows that the analytical method in this paper is valid, which provides a new method of theoretical study for the elastic-plastic buckling of the member.

Abstract: The paper presents the compatibility relation of displacement, strain energy expression, and the formulations of Finite Element Method in the transitional region for the improved damage model of 2-D delamination[1]. The postbuckling behaviors of composite laminated plate with a circular delamination are analyzed. Results show that the model mainly improves computational results of energy release rates in the delamination front. The model should only be used in a narrow region near the crack-tip and the normal Mindlin model in other regions. It leads to little increase in the amount of computation, but significant improvement in the results.