Acta Mechanica Sinica
     Acta Mechanica Sinica
  Acta Mechanica Sinica--2015, 31 (3)   Published: 20 July 2015
Recent progress in compressible turbulence Hot!
Shiyi Chen, Zhenhua Xia, Jianchun Wang, Yantao Yang
In this paper, we review some recent studies on compressible turbulence conducted by the authors' group, which include fundamental studies on compressible isotropic turbulence (CIT) and applied studies on developing a constrained large eddy simulation (CLES) for wall-bounded turbulence. In the first part, we begin with a newly proposed hybrid compact-weighted essentially nonoscillatory (WENO) scheme for a CIT simulation that has been used to construct a systematic database of CIT. Using this dat...
A review of research on nanoparticulate flow undergoing coagulation Hot!
Jianzhong Lin, Linlin Huo

Nanoparticulate flows occur in a wide range of natural phenomena and engineering applications and, hence, have attracted much attention. The purpose of the present paper is to provide a review of the research conducted over the last decade. The research covered relates to the Brownian coagulation of monodisperse and polydisperse particles, the Taylor-series expansion method of moment, and nanoparticle distributions due to coagulation in pipe and channel flow, jet flow, and the mixing layer an...

Direct modeling for computational fluid dynamics Hot!
Kun Xu

All fluid dynamic equations are valid under their modeling scales, such as the particle mean free path and mean collision time scale of the Boltzmann equation and the hydrodynamic scale of the Navier-Stokes (NS) equations. The current computational fluid dynamics (CFD) focuses on the numerical solution of partial differential equations (PDEs), and its aim is to get the accurate solution of these governing equations. Under such a CFD practice, it is hard to develop a unified scheme that covers...

The mechanical behavior of nanoscale metallic multilayers: A survey Hot!
Q. Zhou, J. Y. Xie, F. Wang, P. Huang, K. W. Xu, T. J. Lu

The mechanical behavior of nanoscale metallic multilayers (NMMs) has attracted much attention from both scientific and practical views. Compared with their monolithic counterparts, the large number of interfaces existing in the NMMs dictates the unique behavior of this special class of structural composite materials. While there have been a number of reviews on the mechanical mechanism of microlaminates, the rapid development of nanotechnology brought a pressing need for an overview focusing ...

A new thermo-elasto-plasticity constitutive theory for polycrystalline metals Hot!
Cen Chen, Qiheng Tang, Tzuchiang Wang

In this study, the behavior of polycrystalline metals at different temperatures is investigated by a new thermo-elasto-plasticity constitutive theory. Based on solid mechanical and interatomic potential, the constitutive equation is established using a new decomposition of the deformation gradient. For polycrystalline copper and magnesium, the stress-strain curves from 77 to 764 K (copper), and 77 to 870 K (magnesium) under quasi-static uniaxial loading are calculated, and then the calculated...

Active elastic metamaterials for subwavelength wave propagation control Hot!
Y. Y. Chen, G. L. Huang

Recent research activities in elastic metamaterials demonstrate a significant potential for subwavelength wave propagation control owing to their interior locally resonant mechanism. The growing technological developments in electro/magnetomechanical couplings of smart materials have introduced a controlling degree of freedom for passive elastic metamaterials. Active elastic metamaterials could allow for a fine control of material physical behavior and thereby induce new functional properties...

Hierarchical structure observation and nanoindentation size effect characterization for a limnetic shell Hot!
Jingru Song, Cuncai Fan, Hansong Ma, Yueguang Wei

In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated biomaterial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic “pillar” structure and a nacreous “brick and mortar” structure. The prismatic layer looks like a “pillar forest” with variationsection pillars sized on the order of se...

Mechanical response of fabric sheets to three-dimensional bending, twisting, and stretching Hot!
David J. Steigmann, Francesco dell'Isola

A model for the mechanics of woven fabrics is developed in the framework of two-dimensional elastic surface theory. Thickness effects are modeled indirectly in terms of appropriate constitutive equations. The model accounts for the strain of the fabric and additional effects associated with the normal bending, geodesic bending, and twisting of the constituent fibers.

A two-parameter model to predict fatigue life of high-strength steels in a very high cycle fatigue regime Hot!
Chengqi Sun, Xiaolong Liu, Youshi Hong

In this paper, ultrasonic (20 kHz) fatigue tests were performed on specimens of a high-strength steel in very high cycle fatigue (VHCF) regime. Experimental results showed that for most tested specimens failed in a VHCF regime, a fatigue crack originated from the interior of specimen with a fish-eye pattern, which contained a fine granular area (FGA) centered by an inclusion as the crack origin.Then, a two-parameter model is proposed to predict the fatigue life of high-strength steels with fi...

Elastoplastic homogenization of particulate composites complying with the Mohr-Coulomb criterion and undergoing isotropic loading Hot!
D. Yang, Q. C. He

This work aims at determining the overall response of a two-phase elastoplastic composite to isotropic loading. The composite under investigation consists of elastic particles embedded in an elastic perfectly plastic matrix governed by the Mohr-Coulomb yield criterion and a non-associated plastic flow rule. The composite sphere assemblage model is adopted, and closed-form estimates are derived for the effective elastoplastic properties of the composite either under tensile or compressive isot...

A high-order full-discretization method using Hermite interpolation for periodic time-delayed differential equations Hot!
Yilong Liu, Achim Fischer, Peter Eberhard, Baohai Wu

A high-order full-discretization method (FDM) using Hermite interpolation (HFDM) is proposed and implemented for periodic systems with time delay. Both Lagrange interpolation and Hermite interpolation are used to approximate state values and delayed state values in each discretization step. The transition matrix over a single period is determined and used for stability analysis. The proposed method increases the approximation order of the semidiscretization method and the FDM without increasi...

Pulling out a peptide chain from β-sheet crystallite: Propagation of instability of H-bonds under shear force Hot!
Changjian Xu, Dechang Li, Yuan Cheng, Ming Liu, Yongwei Zhang, Baohua Ji

Anti-parallel β-sheet crystallite as themain component of silk fibroin has attracted much attention due to its superiormechanical properties. In this study,we examine the processes of pulling a peptide chain from β-sheet crystallite using steered molecular dynamics simulations to investigate the rupture behavior of the crystallite.We show that the failure of β-sheet crystallite was accompanied by a propagation of instability of hydrogen-bonds (H-bonds) in the crystallite. In ad...

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