当期目录

2015年 第36卷 第12期    刊出日期：2015-12-01

上一期    下一期

Analysis of thickness-shear and thickness-twist modes of AT-cut quartz acoustic wave resonator and filter

Zinan ZHAO, Zhenghua QIAN, Bin WANG, Jiashi YANG

2015, 36(12):  1527-1538.  doi:10.1007/s10483-015-2008-6

摘要 ( 625 )   HTML   PDF (733KB) ( 312 )  

参考文献 | 相关文章 | 多维度评价

The thickness-shear (TS) and thickness-twist (TT) vibrations of partially electroded AT-cut quartz plates for acoustic wave resonator and filter applications are theoretically studied. The plates have structural variations in one of the two in-plane directions of the plates only. The scalar differential equations derived by Tiersten and Smythe for electroded and unelectroded AT-cut quartz plates are used, resulting in free vibration resonant frequencies and mode shapes for both fundamental and overtone families of modes. The trapped modes with vibrations, mainly confined in the electroded areas, are found to exist in both the resonator and the filter structures. The numerical results for the trapped modes are presented for different aspect ratios of electrodes and material properties, providing a reference to the design and optimization of quartz acoustic wave resonators and filters.



New approach based on continuum damage mechanics with simple parameter identification to fretting fatigue life prediction

Fei SHEN, Weiping HU, Qingchun MENG

2015, 36(12):  1539-1554.  doi:10.1007/s10483-015-2002-6

摘要 ( 641 )   HTML   PDF (902KB) ( 248 )  

参考文献 | 相关文章 | 多维度评价

A new continuum damage mechanics model for fretting fatigue life prediction is established. In this model, the damage evolution rate is described by two kinds of quantities. One is associated with the cyclic stress characteristics obtained by the finite element(FE) analysis, and the other is associated with the material fatigue property identified from the fatigue test data of standard specimens. The wear is modeled by the energy wear law to simulate the contact geometry evolution. A two-dimensional(2D) plane strain FE implementation of the damage mechanics model and the energy wear model is presented in the platform of ABAQUS to simulate the evolutions of the fatigue damage and the wear scar. The effect of the specimen thickness is also investigated. The predicted results of the crack initiation site and the fretting fatigue life agree well with available experimental data. Comparisons are made with the critical plane SmithWatson-Topper(SWT) method.

Sensitivity analysis of pull-in voltage for RF MEMS switch based on modified couple stress theory

Junhua ZHU, Renhuai LIU

2015, 36(12):  1555-1568.  doi:10.1007/s10483-015-2005-6

摘要 ( 541 )   HTML   PDF (445KB) ( 123 )  

参考文献 | 相关文章 | 多维度评价

An approximate analytical model for calculating the pull-in voltage of a stepped cantilever-type radio frequency(RF) micro electro-mechanical system(MEMS) switch is developed based on the Euler-Bernoulli beam and a modified couple stress theory, and is validated by comparison with the finite element results. The sensitivity functions of the pull-in voltage to the designed parameters are derived based on the proposed model. The sensitivity investigation shows that the pull-in voltage sensitivities increase/decrease nonlinearly with the increases in the designed parameters. For the stepped cantilever beam, there exists a nonzero optimal dimensionless length ratio, where the pull-in voltage is insensitive. The optimal value of the dimensionless length ratio only depends on the dimensionless width ratio, and can be obtained by solving a nonlinear equation. The determination of the designed parameters is discussed, and some recommendations are made for the RF MEMS switch optimization.

Two kinds of contact problems in three-dimensional icosahedral quasicrystals

Xuefen ZHAO, Xing LI, Shenghu DING

2015, 36(12):  1569-1580.  doi:10.1007/s10483-015-2006-6

摘要 ( 556 )   HTML   PDF (234KB) ( 200 )  

参考文献 | 相关文章 | 多维度评价

Two kinds of contact problems, i.e., the frictional contact problem and the adhesive contact problem, in three-dimensional(3D) icosahedral quasicrystals are discussed by a complex variable function method. For the frictional contact problem, the contact stress exhibits power singularities at the edge of the contact zone. For the adhesive contact problem, the contact stress exhibits oscillatory singularities at the edge of the contact zone. The numerical examples show that for the two kinds of contact problems, the contact stress exhibits singularities, and reaches the maximum value at the edge of the contact zone. The phonon-phason coupling constant has a significant effect on the contact stress intensity, while has little impact on the contact stress distribution regulation. The results are consistent with those of the classical elastic materials when the phonon-phason coupling constant is 0. For the adhesive contact problem, the indentation force has positive correlation with the contact displacement, but the phonon-phason coupling constant impact is barely perceptible. The validity of the conclusions is verified.

Polymer translocation through nanopore under external electric field:dissipative particle dynamics study

Jinglin MAO, Yi YAO, Zhewei ZHOU, Guohui HU

2015, 36(12):  1581-1592.  doi:10.1007/s10483-015-2062-6

摘要 ( 476 )   HTML   PDF (495KB) ( 156 )  

参考文献 | 相关文章 | 多维度评价

The DNA sequencing technology has achieved a leapfrog development in recent years. As a new generation of the DNA sequencing technology, nanopore sequencing has shown a broad application prospect and attracted vast research interests since it was proposed. In the present study, the dynamics of the electric-driven translocation of a homopolymer through a nanopore is investigated by the dissipative particle dynamics(DPD), in which the homopolymer is modeled as a worm-like chain(WLC). The DPD simulations show that the polymer chain undergoes conformation changes during the translocation process. The different structures of the polymer in the translocation process, i.e., single-file, double folded, and partially folded, and the induced current blockades are analyzed. It is found that the current blockades have different magnitudes due to the polymer molecules traversing the pore with different folding conformations. The nanoscale vortices caused by the concentration polarization layers(CPLs) in the vicinity of the sheet are also studied. The results indicate that the translocation of the polymer has the effect of eliminating the vortices in the polyelectrolyte solution. These findings are expected to provide the theoretical guide for improving the nanopore sequencing technique.

论文

Entropy analysis of unsteady magneto-nanofluid flow past accelerating stretching sheet with convective boundary condition

S. DAS, S. CHAKRABORTY, R. N. JANA, O. D. MAKINDE

2015, 36(12):  1593-1610.  doi:10.1007/s10483-015-2003-6

摘要 ( 671 )   HTML   PDF (683KB) ( 431 )  

参考文献 | 相关文章 | 多维度评价

The unsteady laminar magnetohydrodynamics(MHD) boundary layer flow and heat transfer of nanofluids over an accelerating convectively heated stretching sheet are numerically studied in the presence of a transverse magnetic field with heat source/sink. The unsteady governing equations are solved by a shooting method with the Runge-KuttaFehlberg scheme. Three different types of water based nanofluids, containing copper, aluminium oxide, and titanium dioxide, are taken into consideration. The effects of the pertinent parameters on the fluid velocity, the temperature, the entropy generation number, the Bejan number, the shear stress, and the heat transfer rate at the sheet surface are graphically and quantitatively discussed in detail. A comparison of the entropy generation due to the heat transfer and the fluid friction is made with the help of the Bejan number. It is observed that the presence of the metallic nanoparticles creates more entropy in the nanofluid flow than in the regular fluid flow.

Unsupervised neural network model optimized with evolutionary computations for solving variants of nonlinear MHD Jeffery-Hamel problem

M. A. Z. RAJA, R. SAMAR, T. HAROON, S. M. SHAH

2015, 36(12):  1611-1638.  doi:10.1007/s10483-015-2000-6

摘要 ( 525 )   HTML   PDF (1404KB) ( 235 )  

参考文献 | 相关文章 | 多维度评价

null

Stability and boundary equilibrium bifurcations of modified Chua's circuit with smooth degree of 3

Shihui FU, Xiangying MENG, Qishao LU

2015, 36(12):  1639-1650.  doi:10.1007/s10483-015-2009-6

摘要 ( 650 )   HTML   PDF (273KB) ( 130 )  

参考文献 | 相关文章 | 多维度评价

Chua's circuit is a well-known nonlinear electronic model, having complicated nonsmooth dynamic behaviors. The stability and boundary equilibrium bifurcations for a modified Chua's circuit system with the smooth degree of 3 are studied. The parametric areas of stability are specified in detail. It is found that the bifurcation graphs of the supercritical and irregular pitchfork bifurcations are similar to those of the piecewise-smooth continuous(PWSC) systems caused by piecewise smoothness. However, the bifurcation graph of the supercritical Hopf bifurcation is similar to those of smooth systems. Therefore, the boundary equilibrium bifurcations of the non-smooth systems with the smooth degree of 3 should receive more attention due to their special features.

Investigation of power-type variational principles in liquid-filled system

Haiyan SONG, Lifu LIANG

2015, 36(12):  1651-1662.  doi:10.1007/s10483-015-2004-6

摘要 ( 522 )   HTML   PDF (147KB) ( 124 )  

参考文献 | 相关文章 | 多维度评价

Starting from the basic equations of hydrodynamics, the maximum powertype variational principle of the hydrodynamics of viscous fluids was established by Weizang CHIEN in 1984. Through long-term research, it is clarified that the maximum power-type variational principle coincides with the Jourdian principle, which is one of the common principles for analytical mechanics. In the paper, the power-type variational principle is extended to rigid-body dynamics, elasto-dynamics, and rigid-elastic-liquid coupling dynamics. The governing equations of the rigid-elastic-liquid coupling dynamics in the liquid-filled system are obtained by deriving the stationary value conditions. The results show that, with the power-type variational principles studied directly in the state space, some transformations in the time domain space may be omitted in the establishing process, and the rigid-elastic-liquid coupling dynamics can be easily numerically modeled. Moreover, the analysis of the coupling dynamics in the liquid-filled system in this paper agrees well with the numerical analyses of the coupling dynamics in the liquid-filled system offered in the literatures.

A system of general nonlinear variational inclusions in Banach spaces

Xieping DING, SALAHUDDIN

2015, 36(12):  1663-1672.  doi:10.1007/s10483-015-2001-6

摘要 ( 524 )   HTML   PDF (155KB) ( 187 )  

参考文献 | 相关文章 | 多维度评价

A new system of general nonlinear variational inclusions is introduced and studied in Banach spaces. An iterative algorithm is developed and analyzed by use of the resolvent operator techniques to find the approximate solutions of the system of general nonlinear variational inclusions involving different nonlinear operators in uniformly smooth Banach spaces.