In this paper motion of rigid rod on a circular surface is studied analytically.A new analytical method called modified homotopy perturbation method(MHPM)is applied for solving this problem in different initial condit...In this paper motion of rigid rod on a circular surface is studied analytically.A new analytical method called modified homotopy perturbation method(MHPM)is applied for solving this problem in different initial conditions to show capability of this method.The goveming equation for motion of a nigid rod on the circular surface without slipping have been solved using MHPM.The efficacy of MHPM for handling nonlinear oscillation systems with various small and large oscillation amplitudes are presented in comparison with numerical benchmarks.Outcomes reveal that MHPM has an excellent agreement with numerical solution.The results show that by decreasing the oscillation amplitude,the velocity of rigid rod decreases and for A=w3 the velocity profile is maximum.展开更多
A vorticity-velocity method was used to study the incompressible viscous fluid flow around a circular cylinder with surface suction or blowing. The resulted high order implicit difference equations were effeciently so...A vorticity-velocity method was used to study the incompressible viscous fluid flow around a circular cylinder with surface suction or blowing. The resulted high order implicit difference equations were effeciently solved by the modified incomplete LU decomposition conjugate gradient scheme ( MILU-CG). The effects of surface suction or blowing' s position and strength on the vortex structures in the cylinder wake, as well as on the drag and lift forces at Reynoldes number Re = 100 were investigated numerically. The results show that the suction on the shoulder of the cylinder or the blowing on the rear of the cylinder can effeciently suppress the asymmetry of the vortex wake in the transverse direction and greatly reduce the lift force; the suction on the shoulder of the cylinder, when its strength is properly chosen, can reduce the drag force significantly, too.展开更多
In this paper, we prove that the surface of any circular cone can be triangulated into 8 non-obtuse and 20 acute triangles. Furthermore, we also show that the bounds are both the best possible.
The proliferation of Hoek-Brown nonlinear failure criterion and upper bound theorem makes it possible to evaluate the stability of circular tunnels with an original curved collapsing mechanism. The arch effect of shal...The proliferation of Hoek-Brown nonlinear failure criterion and upper bound theorem makes it possible to evaluate the stability of circular tunnels with an original curved collapsing mechanism. The arch effect of shallow circle tunnel is not taken into consideration so that the mechanical characteristics can be easily described. Based on the mechanism, the upper bound solution of supporting pressure of tunnels under the condition of surface settlements and overloads on the ground surface is derived. The objective function is formed from virtual work equations under the variational principle, and solutions are presented by the optimum theory. Comparisons with previous works are made. The numerical results of the present method show great agreement with those of existing ones. With regard to the surface settlement and overloads, the influence of different rock parameters on the collapsing shape is analyzed.展开更多
While the soil nails and the corresponding compound technology are widely used as the support techniques for deep foundation pit and normal slopes, few related engineering cases are found for high loess slopes. By uti...While the soil nails and the corresponding compound technology are widely used as the support techniques for deep foundation pit and normal slopes, few related engineering cases are found for high loess slopes. By utilizing the finite element software of PLAXIS 8.5, the behavior of a high loess slope reinforced by the combination of soil nails and stabilization piles （hereinafter for CSNSP） is studied in this paper. It can be found that the potential slide surface of the slope moves to deeper locations during the process of the multi-staged excavations. The measure of reducing the weight of the top of the slope is a positive factor to the stability of the loess slope, while the rainfhll is a negative factor. The slope can＇t be stable if it＇s reinforced only by stabilization piles or soil nails during the process of the multi-staged excavations. The soil nail contributes greater to the overall system stability when the excavation depth is relatively shallow, while the stabilization pile takes it over when the excavation depth reaches a large value. Compared to the results from the Sweden circular slip surface, the data derived from the method of phi/c reduction is relatively large when the slope is unreinforced or reinforced only by stabilization pile, and the data turns to be small when the slope is strengthened by soil nails or the combination system of soil nails and stabilization piles.展开更多
文摘In this paper motion of rigid rod on a circular surface is studied analytically.A new analytical method called modified homotopy perturbation method(MHPM)is applied for solving this problem in different initial conditions to show capability of this method.The goveming equation for motion of a nigid rod on the circular surface without slipping have been solved using MHPM.The efficacy of MHPM for handling nonlinear oscillation systems with various small and large oscillation amplitudes are presented in comparison with numerical benchmarks.Outcomes reveal that MHPM has an excellent agreement with numerical solution.The results show that by decreasing the oscillation amplitude,the velocity of rigid rod decreases and for A=w3 the velocity profile is maximum.
基金Foundation item:the Natural Science Foundation of Jiangsu Province(BK97056109)
文摘A vorticity-velocity method was used to study the incompressible viscous fluid flow around a circular cylinder with surface suction or blowing. The resulted high order implicit difference equations were effeciently solved by the modified incomplete LU decomposition conjugate gradient scheme ( MILU-CG). The effects of surface suction or blowing' s position and strength on the vortex structures in the cylinder wake, as well as on the drag and lift forces at Reynoldes number Re = 100 were investigated numerically. The results show that the suction on the shoulder of the cylinder or the blowing on the rear of the cylinder can effeciently suppress the asymmetry of the vortex wake in the transverse direction and greatly reduce the lift force; the suction on the shoulder of the cylinder, when its strength is properly chosen, can reduce the drag force significantly, too.
文摘In this paper, we prove that the surface of any circular cone can be triangulated into 8 non-obtuse and 20 acute triangles. Furthermore, we also show that the bounds are both the best possible.
基金Project(2013CB036004)supported by the National Basic Research Program of ChinaProjects(51178468,51378510)supported by the National Natural Science Foundation of China
文摘The proliferation of Hoek-Brown nonlinear failure criterion and upper bound theorem makes it possible to evaluate the stability of circular tunnels with an original curved collapsing mechanism. The arch effect of shallow circle tunnel is not taken into consideration so that the mechanical characteristics can be easily described. Based on the mechanism, the upper bound solution of supporting pressure of tunnels under the condition of surface settlements and overloads on the ground surface is derived. The objective function is formed from virtual work equations under the variational principle, and solutions are presented by the optimum theory. Comparisons with previous works are made. The numerical results of the present method show great agreement with those of existing ones. With regard to the surface settlement and overloads, the influence of different rock parameters on the collapsing shape is analyzed.
基金Acknowledgements This research was supported by the National Nature Science Foundation of China （Grant Nos. 41172260, 41372292, 5 l 108393）, the National Basic Research Program of China （Grant No. 2008CB425801）, and the Specialized Research Fund for the Doctoral Program of Higher Education （No. 20110184110018） as well as the Doctoral Student Innovation Fund of South-west Jiaotong University.
文摘While the soil nails and the corresponding compound technology are widely used as the support techniques for deep foundation pit and normal slopes, few related engineering cases are found for high loess slopes. By utilizing the finite element software of PLAXIS 8.5, the behavior of a high loess slope reinforced by the combination of soil nails and stabilization piles （hereinafter for CSNSP） is studied in this paper. It can be found that the potential slide surface of the slope moves to deeper locations during the process of the multi-staged excavations. The measure of reducing the weight of the top of the slope is a positive factor to the stability of the loess slope, while the rainfhll is a negative factor. The slope can＇t be stable if it＇s reinforced only by stabilization piles or soil nails during the process of the multi-staged excavations. The soil nail contributes greater to the overall system stability when the excavation depth is relatively shallow, while the stabilization pile takes it over when the excavation depth reaches a large value. Compared to the results from the Sweden circular slip surface, the data derived from the method of phi/c reduction is relatively large when the slope is unreinforced or reinforced only by stabilization pile, and the data turns to be small when the slope is strengthened by soil nails or the combination system of soil nails and stabilization piles.
