A classification of poromechanical interface elements

Interface elements are a classical approach to represent discrete cracks, joints and faults. The basic kinematic and constitutive aspects are recapitulated and the extension to hydromechanical conditions is elaborated. A classification is presented of hydromechanical interface elements, depending on the multiplicity of the pressure degree of freedom, and the physical implications of the different possibilities are explained.

Red blood cell (RBC) aggregation and its influence on non-Newtonian nature of blood in microvasculature

A robust computational model is proposed to investigate the non-Newtonian nature of blood flow due to rouleaux formation in microvasculature. The model consists of appropriate forces responsible for red blood cell (RBC) aggregation in the microvasculature, tracking of RBCs, and coupling between plasma flow and RBCs. The RBC aggregation results have been compared against the available data. The importance of different hydrodynamic forces on red blood cell aggregation has been delineated by comparing the time dependent path of the RBCs. The rheological changes to the blood flow have been investigated under different shear rates and hematocrit values and quantified with and without RBC aggregation. The results obtained in terms of wall shear stress (WSS) and blood viscosity indicate a significant difference between Newtonian and powerlaw fluid assumptions.

Nonlocal elasticity theory for graphene modeling and simulation: prospects and challenges

This paper presents a literature review of recent research studies on the applications of nonlocal elasticity theory in the modeling and simulation of graphene sheets (GSs). The history, development and excellent properties of GSs are introduced. The details of nonlocal elasticity theory are also presented. A systematic introduction to the application of nonlocal elasticity on linear modeling and nonlinear modeling for single-layer graphene sheets (SLGSs) and multilayered graphene sheets (MLGSs) is also provided. The necessity of determining mechanical parameters and nonlocal parameters is discussed. Recommendations for future work are particularly presented. This work is intended to review the development of GSs, give an introduction to the research studies on nonlocal elasticity theory in the modeling of GSs, and provide recommendations for future research.

Geometrically nonlinear large deformation of CNT-reinforced composite plates with internal column supports

The geometrical nonlinear analysis of internally supported nanocomposite plates subjected to a uniformly distributed load is carried out. This study investigates the effects of internal point/column supports on the large deformation bending of nanocomposite plates reinforced by carbon nanotubes (CNTs) with different types of distributions, namely, uniform and two kinds of functionally graded distributions through the thickness of the plates. Two-dimensional displacement field of the plate is approximated by a set of Improved Moving Least Squares (IMLS) functions. The arc-length iterative algorithm with the modified Newton method is employed to obtain the nonlinear response of nanocomposite plates. Convergence studies indicate the validity and effectiveness of the element-free IMLS-Ritz method. The effects of plate thickness-to-width ratio, volume fraction ratio, and plate aspect ratio on the large deformation behavior of nanocomposite plates under various boundary conditions are examined. To the best of the authors’ knowledge, the problem has not been attempted in the open literature.

A studying on load transfer in carbon nanotube/epoxy composites under tension

The shear-lag model is developed to study the effect of geometry and material properties of epoxy and carbon nanotubes on load transfer in carbon nanotube/epoxy composites under tension. The results from proposed shear-lag model are validated by finite element method and the Haque’s model. Results show that the aspect ratio of the half-length to the outer radius of carbon nanotubes and their layer number have significant influence on load transfer in the composites. On the other hand, this research reveals new findings, which are not reported in other previous works. That is, no noticeable influences of the epoxy Young’s modulus and the interface shear modulus between epoxy matrix and carbon nanotube layers are found on load transfer in terms of the saturated stress length. In addition, the carbon nanotube volume percentage is found not affecting the load transfer. This research presents a better understanding on mechanical properties of carbon nanotube/epoxy composites.

Magnetoelectric effects in bilayer multiferroic core-shell composites

We investigate magnetoelectric (ME) effects in bilayer multiferroic core-shell composites in this paper. The composites are driven by the radial magnetic field and the induced radial deformation/vibration is studied. Two configurations are considered in a concise and uniform manner mathematically. One is spherical and the other is cylindrical. For bilayer core-shell composites, we show that the geometric configuration has a significant effect on the ME effect in multiferroic core-shell composites for both low-frequency and electromechanical resonance ranges. At the low-frequency range, except for the mechanically clamped case, the ME effects in spherical multiferroic composites are always stronger than that in cylindrical ones. At the electromechanical resonance range, for traction-free case, the fundamental resonance frequency of the spherical multiferroic composite is higher than that of the cylindrical one and thus the corresponding ME effect in spherical composite is stronger than that in cylindrical one.