当期目录

2020年 第41卷 第4期    刊出日期：2020-04-01

上一期    下一期

论文

Atomic-scale simulations for lithium dendrite growth driven by strain gradient

Gao XU, Feng HAO, Jiawang HONG, Daining FANG

2020, 41(4):  533-542.  doi:10.1007/s10483-020-2596-5

摘要 ( 417 )   HTML ( 17)   PDF (1552KB) ( 153 )  

参考文献 | 相关文章 | 多维度评价

Dendrite formation is a major obstacle, e.g., capacity loss and short circuit, to the next-generation high-energy-density lithium (Li)-metal batteries. The development of successful Li dendrite mitigation strategies is impeded by an insufficient understanding in Li dendrite growth mechanisms. The Li-plating-induced internal stress in Li-metal and its effects on dendrite growth have been widely studied, but the underlying microcosmic mechanism is elusive. In the present study, the role of the plating-induced stress in dendrite formation is analyzed through first-principles calculations and ab initio molecular dynamic (AIMD) simulations. It is shown that the deposited Li forms a stable atomic nanofilm structure on the copper (Cu) substrate, and the adsorption energy of Li atoms increases from the Li-Cu interface to the deposited Li surface, leading to more aggregated Li atoms at the interface. Compared with the pristine Li-metal, the deposited Li in the early stage becomes compacted and suffers the in-plane compressive stress. Interestingly, there is a giant strain gradient distribution from the Li-Cu interface to the deposited Li surface, making the deposited atoms adjacent to the Cu surface tend to press upwards with perturbation and causing the dendrite growth. This provides an insight into the atomicscale origin of Li dendrite growth, and may be useful for suppressing the Li dendrite in Li-metal-based rechargeable batteries.



Practical Green’s function for the thermal stress field induced by a heat source in plane thermoelasticity

Jian HUA, Ming DAI

2020, 41(4):  543-550.  doi:10.1007/s10483-020-2597-8

摘要 ( 385 )   HTML ( 3)   PDF (205KB) ( 119 )  

参考文献 | 相关文章 | 多维度评价

The classical Green’s functions used in the literature for a heat source in a homogeneous elastic medium cannot lead to finite remote thermal stresses in the medium, so that they may not work well in practical thermal stress analyses. In this paper, we develop a practical Green’s function for a heat source disposed eccentrically into an elastic disk/cylinder subject to plane deformation. The edge of the disk/cylinder is assumed to be thermally permeable and traction-free. The full thermal stress field induced by the heat source in the disk/cylinder is determined exactly and explicitly via the Cauchy integral techniques. In particular, a very simple formula is obtained to describe the hoop thermal stress on the edge of the disk/cylinder, which may be conveniently useful for analyzing the thermal stresses in microelectronic components.

A numerical method based on boundary integral equations and radial basis functions for plane anisotropic thermoelastostatic equations with general variable coefficients

W. T. ANG, X. WANG

2020, 41(4):  551-566.  doi:10.1007/s10483-020-2592-8

摘要 ( 390 )   HTML ( 6)   PDF (382KB) ( 579 )  

参考文献 | 相关文章 | 多维度评价

A boundary integral method with radial basis function approximation is proposed for numerically solving an important class of boundary value problems governed by a system of thermoelastostatic equations with variable coefficients. The equations describe the thermoelastic behaviors of nonhomogeneous anisotropic materials with properties that vary smoothly from point to point in space. No restriction is imposed on the spatial variations of the thermoelastic coefficients as long as all the requirements of the laws of physics are satisfied. To check the validity and accuracy of the proposed numerical method, some specific test problems with known solutions are solved.

Non-uniform rational B-spline based free vibration analysis of axially functionally graded tapered Timoshenko curved beams

Zhiwei ZHOU, Meixia CHEN, Kun XIE

2020, 41(4):  567-586.  doi:10.1007/s10483-020-2594-7

摘要 ( 428 )   HTML ( 6)   PDF (1525KB) ( 70 )  

参考文献 | 相关文章 | 多维度评价

The free vibration of axially functionally graded (FG) tapered Timoshenko curved beams is studied with the numerical approach. By using the non-uniform rational B-spline (NURBS) basis functions, the exact geometry and the generalized displacement field are formulated. Variable geometric parameters and material properties, including the curvature, cross-sectional area, area moment of inertia, mass density, and Young’s modulus, are expanded as functions of the coordinate in a parametric domain. Based on Hamilton’s principle, the weak formulation is derived by applying a refined constitutive relation which considers the thickness effect. Natural frequencies and mode shapes are obtained from the eigenvalue equation. Circular, elliptic, and parabolic curved beams are considered in numerical examples. The obtained results are in good agreement with those in the existing studies and those calculated by the finite element software ANSYS. Moreover, the effects of the material gradient, taper ratio, slenderness ratio, and heightspan ratio on vibration behaviors are discussed.

Size-dependent shear buckling response of FGM skew nanoplates modeled via different homogenization schemes

Yuan YUAN, Ke ZHAO, S. SAHMANI, B. SAFAEI

2020, 41(4):  587-604.  doi:10.1007/s10483-020-2600-6

摘要 ( 449 )   HTML ( 3)   PDF (587KB) ( 72 )  

参考文献 | 相关文章 | 多维度评价

The size effects on the shear buckling behaviors of skew nanoplates made of functionally graded materials (FGMs) are presented. The material properties are supposed to be changed uniformly from the ceramic phase to the metal one along the plate thickness. To estimate the associated effective material properties, various homogenization schemes including the Reuss model, the Voigt model, the Mori-Tanaka model, and the Hashin-Shtrikman bound model are used. The nonlocal elasticity theory together with the oblique coordinate system is applied to the higher-order shear deformation plate theory to develop a size-dependent plate model for the shear buckling analysis of FGM skew nanoplates. The Ritz method using Gram-Schmidt shape functions is used to solve the size-dependent problem. It is found that the significance of the nonlocality in the reduction of the shear buckling load of an FGM skew nanoplate increases for a higher value of the material property gradient index. Also, by increasing the skew angle, the critical shear buckling load of an FGM skew nanoplate enhances. This pattern becomes a bit less significant for a higher value of the material property gradient index. Furthermore, among various homogenization models, the Voigt and Reuss models in order estimate the overestimated and underestimated shear buckling loads, and the difference between them reduces by increasing the aspect ratio of the skew nanoplate.

Approximate analytical solution in slow-fast system based on modified multi-scale method

Xianghong LI, Jianhua TANG, Yanli WANG, Yongjun SHEN

2020, 41(4):  605-622.  doi:10.1007/s10483-020-2598-9

摘要 ( 665 )   HTML ( 1)   PDF (1233KB) ( 131 )  

参考文献 | 相关文章 | 多维度评价

A simple, yet accurate modified multi-scale method (MMSM) for an approximately analytical solution in nonlinear oscillators with two time scales under forced harmonic excitation is proposed. This method depends on the classical multi-scale method (MSM) and the method of variation of parameters. Assuming that the forced excitation is a constant, one could easily obtain the approximate analytical solution of the simplified system based on the traditional MSM. Then, this solution for the oscillator under forced harmonic excitation could be established after replacing the harmonic excitation by the constant excitation. To certify the correctness and precision of the proposed analytical method, the van der Pol system with two scales subject to slowly periodic excitation is investigated; this system presents rich dynamical phenomena such as spiking (SP), spiking-quiescence (SP-QS), and quiescence (QS) responses. The approximate analytical expressions of the three types of responses are given by the MMSM, and it can be found that the precision of the new analytical method is higher than that of the classical MSM and better than that of the harmonic balance method (HBM). The results obtained by the present method are considerably better than those obtained by traditional methods, quantitatively and qualitatively, particularly when the excitation frequency is far less than the natural frequency of the system.

Interaction effects of DNA, RNA-polymerase, and cellular fluid on the local dynamic behaviors of DNA

Weipeng HU, Zichen DENG

2020, 41(4):  623-636.  doi:10.1007/s10483-020-2595-6

摘要 ( 368 )   HTML ( 3)   PDF (1303KB) ( 111 )  

参考文献 | 相关文章 | 多维度评价

In view of the complex structure and environment, the dynamic analysis on deoxyribonucleic acid (DNA) is a challenge in the biophysics field. Considering the local interaction with ribonucleic acid (RNA)-polymerase as well as the dissipative effect of cellular fluid, a coupling sine-Gordon-type dynamic model is used to describe the rotational motions of the bases in DNA. First, the approximate symmetric form is constructed. Then, the wave form and the wave velocity of the kink solution to the proposed dynamic model are investigated by a Runge-Kutta structure-preserving scheme based on the generalized multi-symplectic idea. The numerical results indicate that, the strengthening of the local interaction between DNA and RNA-polymerase described by the coupling potential makes the form of the kink solution steep, while the appearance of the friction between DNA and cellular fluid makes the form of the kink solution flat. In addition, the appearance of the friction decreases the velocities of both the symplectic configuration and the anti-symplectic configuration with different degrees. The above findings are beneficial to comprehend the DNA transcription mechanism.

Effects of magnetic Reynolds number on swimming of gyrotactic microorganisms between rotating circular plates filled with nanofluids

Lijun ZHANG, M. B. ARAIN, M. M. BHATTI, A. ZEESHAN, H. HAL-SULAMI

2020, 41(4):  637-654.  doi:10.1007/s10483-020-2599-7

摘要 ( 455 )   HTML ( 6)   PDF (982KB) ( 222 )  

参考文献 | 相关文章 | 多维度评价

The three-dimensional (3D) nanofluid flow among the rotating circular plates filled with nanoparticles and gyrotactic microorganisms is studied. A generalized form of the magnetic Reynolds number is used for the mathematical modeling of the ferro-nanofluid flow. The torque effects on the lower and upper plates are calculated. A differential transform scheme with the Padé approximation is used to solve the coupled highly nonlinear ordinary differential equations. The results show that the squeeze Reynolds number significantly suppresses the temperature, microorganism, and nanoparticle concentration distribution, and agree well with those obtained by the numerical method.

Transient flow of magnetized Maxwell nanofluid: Buongiorno model perspective of Cattaneo-Christov theory

M. KHAN, A. AHMED, J. AHMED

2020, 41(4):  655-666.  doi:10.1007/s10483-020-2593-9

摘要 ( 453 )   HTML ( 1)   PDF (664KB) ( 114 )  

参考文献 | 相关文章 | 多维度评价

The present research article is devoted to studying the characteristics of Cattaneo-Christov heat and mass fluxes in the Maxwell nanofluid flow caused by a stretching sheet with the magnetic field properties. The Maxwell nanofluid is investigated with the impact of the Lorentz force to examine the consequence of a magnetic field on the flow characteristics and the transport of energy. The heat and mass transport mechanisms in the current physical model are analyzed with the modified versions of Fourier’s and Fick’s laws, respectively. Additionally, the well-known Buongiorno model for the nanofluids is first introduced together with the Cattaneo-Christov heat and mass fluxes during the transient motion of the Maxwell fluid. The governing partial differential equations (PDEs) for the flow and energy transport phenomena are obtained by using the Maxwell model and the Cattaneo-Christov theory in addition to the laws of conservation. Appropriate transformations are used to convert the PDEs into a system of nonlinear ordinary differential equations (ODEs). The homotopic solution methodology is applied to the nonlinear differential system for an analytic solution. The results for the time relaxation parameter in the flow, thermal energy, and mass transport equations are discussed graphically. It is noted that higher values of the thermal and solutal relaxation time parameters in the Cattaneo-Christov heat and mass fluxes decline the thermal and concentration fields of the nanofluid. Further, larger values of the thermophoretic force enhance the heat and mass transport in the nanoliquid. Moreover, the Brownian motion of the nanoparticles declines the concentration field and increases the temperature field. The validation of the results is assured with the help of numerical tabular data for the surface velocity gradient.

Boundary layer flow of Maxwell fluid due to torsional motion of cylinder: modeling and simulation

M. KHAN, A. AHMED, J. AHMED

2020, 41(4):  667-680.  doi:10.1007/s10483-020-2601-5

摘要 ( 476 )   HTML ( 5)   PDF (837KB) ( 163 )  

参考文献 | 相关文章 | 多维度评价

This paper investigates the boundary layer flow of the Maxwell fluid around a stretchable horizontal rotating cylinder under the influence of a transverse magnetic field. The constitutive flow equations for the current physical problem are modeled and analyzed for the first time in the literature. The torsional motion of the cylinder is considered with the constant azimuthal velocity E. The partial differential equations (PDEs) governing the torsional motion of the Maxwell fluid together with energy transport are simplified with the boundary layer concept. The current analysis is valid only for a certain range of the positive Reynolds numbers. However, for very large Reynolds numbers, the flow becomes turbulent. Thus, the governing similarity equations are simplified through suitable transformations for the analysis of the large Reynolds numbers. The numerical simulations for the flow, heat, and mass transport phenomena are carried out in view of the bvp4c scheme in MATLAB. The outcomes reveal that the velocity decays exponentially faster and reduces for higher values of the Reynolds numbers and the flow penetrates shallower into the free stream fluid. It is also noted that the phenomenon of stress relaxation, described by the Deborah number, causes to decline the flow fields and enhance the thermal and solutal energy transport during the fluid motion. The penetration depth decreases for the transport of heat and mass in the fluid with the higher Reynolds numbers. An excellent validation of the numerical results is assured through tabular data with the existing literature.