应用数学和力学

2016 Vol. 37, No. 8

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Only symplectic conservation is characteristic of discrete dynamics

ZHONG Wan-xie

2016, 37(8): 775-777. doi: 10.21656/1000-0887.370186

Abstract(1656) PDF(1066)

Abstract:
Symplectic conservation is altered to "(geometric) structurepreserving" in some foreign work. "Symplectic" is a terminology, but what "structure" means here is still a fuzzy concept that can’t be stated clearly. This alteration seems to make a foreign original achievement. Hence the foreign fuzzifi...

Solutions of Symmetries for Piezoelectric Stack Actuators

XIE Yu, FU Jing-li, CHEN Ben-yong

2016, 37(8): 778-790. doi: 10.21656/1000-0887.370048

Abstract(1185) PDF(774)

Abstract:
The symmetries of piezoelectric stack actuators were investigated, and the solutions of conserved quantities and symmetries were given. The piezoelectric stack actuator of axial movement was considered and its structural characteristics were analyzed, accordingly the displacement and the flux linkag...

Analysis on Shear Deformation and Shear-lag Effects on Twin-Cell Box Girders

ZHANG Hui, ZHANG Yu-yuan, ZHANG Yuan-hai, LI Wei

2016, 37(8): 791-803. doi: 10.21656/1000-0887.370056

Abstract(1714) PDF(847)

Abstract:
Based on the flanges’ different maximum shear angle differences selected as the shear-lag generalized displacements, the energy variational principle was applied to deduce the shear-lag differential equations for twin-cell box girders with and without shear deformation in consideration, and the init...

A Partial Functional Differential Method for Shear Lag Analysis of Composite Double-Cell Box Girders

YU Jiang, HU Shao-wei

2016, 37(8): 804-819. doi: 10.21656/1000-0887.370112

Abstract(1239) PDF(762)

Abstract:
The shear lag effects caused large deformation and significant damage of some structural members in engineering, and had unfavorable influences on engineering safety. To deepen the understanding of the shear lag mechanism, the partial functional differential system for steel-concrete composite doubl...

Preconditioned Conjugate Gradient Methods for the 3D Wilson Nonconforming FEM Discretizations

XIAO Ying-xiong, LI Zhen-you

2016, 37(8): 820-831. doi: 10.21656/1000-0887.370037

Abstract(1599) PDF(550)

Abstract:
The nonconforming finite element method (FEM) is an efficient method to overcome the volume locking trouble in 3D elasticity problems. This method has the advantages of a few degrees of freedom and high accuracy. In order to improve the overall efficiency of the FEM analysis, it is necessary to desi...

Global Synchronization of Complex-Valued Neural Networks With Leakage Time Delays

YAN Huan, ZHAO Zhen-jiang, SONG Qian-kun

2016, 37(8): 832-841. doi: 10.21656/1000-0887.370168

Abstract(1554) PDF(1050)

Abstract:
The global synchronization of complex-valued neural networks with leakage time delays was investigated. For the considered complex-valued neural networks, the activation functions need not be separated into real parts and imaginary parts. Through the construction of appropriate Lyapunov-Krasovskii f...

A Local Stabilized Nonconforming Finite Element Method for the Optimal Control of Navier-Stokes Equations

QIN Yan-mei, LI Hui, FENG Min-fu

2016, 37(8): 842-855. doi: 10.21656/1000-0887.370137

Abstract(1469) PDF(529)

Abstract:
For the optimal control of Navier-Stokes equations, a new local stabilized nonconforming finite element method was proposed. The time-dependent problem was fully discretized with lowest-equal-order nonconforming finite element NCP₁-Psub>1in the velocity and pressure spaces and the reduced Crank-N...

Properties of Positive Solutions to Sturm-Liouville Boundary Value Problems With p-Laplace Operators

YANG Jing-bao

2016, 37(8): 856-862. doi: 10.21656/1000-0887.370047

Abstract(1477) PDF(648)

Abstract:
The properties of positive solutions were investigated for a class of SturmLiouville boundary value problems with p-Laplace operators. Based on the properties of p-Laplace operators, and according to the L’H?pital’s rule and the extreme value theorem for continuous functions on closed intervals, th...

Instability of Aircraft Multiple Trailing Vortex Pairs

CHEN Li-fang, WANG Zhi-bo, SUN Gang

2016, 37(8): 863-872. doi: 10.21656/1000-0887.370059

Abstract(1512) PDF(806)

Abstract:
For aircrafts the wake vortex separation and the disturbance-induced vortex instability draw more and more concerns. A 1st-order approximation of the Biot-Savart law was used to build the induced motion model for arbitrarily multiple vortex pairs. Symmetric and antisymmetric modes of the induced mot...

Effects of Pore Structure on Hydrodynamic Lubrication of Multi-Layer Oil Bearings

ZHANG Guo-tao, YIN Yan-guo, LI Ji-ning, LIU Zhen-ming, TIAN Ming

2016, 37(8): 873-879. doi: 10.21656/1000-0887.360296

Abstract(1065) PDF(683)

Abstract:
The hydrodynamic lubrication model for multi-layer oil bearings was established based on the Darcy’s law. The pores’effects depicted with the Kozeny-Carman equation were considered in the analysis. The effects of the bearing structure and the pore structure on the lubrication properties were simulat...

Study on MHD Stagnation-Point Flow Over Permeable Stretching Sheets With 2nd-Order Slip Boundaries

XU Xiao-qin, CHEN Shu-mei

2016, 37(8): 880-888. doi: 10.21656/1000-0887.370032

Abstract(1565) PDF(573)

Abstract:
The incompressible MHD viscous flow with 2nd-order slip about stagnation points over permeable exponentially stretching sheets in porous media was studied. The governing equations describing the stagnation point flow were reduced to nonlinear differential equations through the similarity transformat...