Jason F. Hammond¹, Elizabeth J. Stewart², John G. Younger³, Michael J.Solomon², David M. Bortz^4,5

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.3, pp. 295-340, 2014, DOI:10.32604/cmes.2014.098.295

Abstract The overall goal of this work is to develop a numerical simulation which correctly describes a bacterial biofilm fluid-structure interaction and separation process. In this, the first of a two-part effort, we fully develop a convergent scheme and provide numerical evidence for the method order as well as a full 3D separation simulation. We use an immersed boundary-based method (IBM) to model and simulate a biofilm with density and viscosity values different from than that of the surrounding fluid. The simulation also includes breakable springs connecting the bacteria in the biofilm which allows the inclusion of erosion and detachment into… More >

Tao Jiang^1,2, Yuan-Sheng Tang¹, Jin-Lian Ren^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.4, pp. 249-297, 2014, DOI:10.3970/cmes.2014.101.249

Abstract In this work, a corrected three-dimensional smoothed particle hydrodynamics (CSPH-3D) method is proposed to simulate the polymer free surface flows in the filling process based on the eXtended Pom-Pom (XPP) model, and some complex deformation phenomena are also numerically predicted. The proposed CSPH-3D method is mainly motivated by a coupled concept that an extended kernel-gradient-corrected SPH (KGC-SPH) method is used in the interior of fluid flow and the traditional SPH (TSPH) method is used near the boundary domain. The present 3D particle method has higher accuracy and better stability than the TSPH-3D method. Meanwhile, a density diffusive term is introduced… More >

Yidong Bao^1,2, Dongmei Wu^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.100, No.4, pp. 277-294, 2014, DOI:10.3970/cmes.2014.100.277

Abstract Aiming at the shortcomings of mass-spring model, this paper, on the basis of preliminary studies, established a new viscoelastic soft tissue model based on meshless structure. The model is consisted of a large quantity of filled spheres, with every three spheres being connected by a spring and a Kelvin structure, which can further enhance the real-time virtual simulation operability while ensure the viscoelasticity of basic model. The stress relaxation and creep equation of the model can be derived from formula derivation. Through setting different parameters to the filled spheres, this model, with certain universal property, can create a virtual liver,… More >

Guanghui Shi¹, Qingsheng Yang^1,2, Xiaoqiao He^3,4, Kim Meow Liew³

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.5, pp. 339-358, 2013, DOI:10.3970/cmes.2013.090.339

Abstract In order to describe the thermomechanical deformation and shape memory effect of shape memory polymers (SMPs), a three-dimensional thermomechanical constitutive model that considers elastic, viscoelastic strain and thermal expansion is proposed for isotropic SMPs. A three-dimensional finite element procedure is developed by implementing the proposed constitutive model into the user material subroutine (UMAT) in ABAQUS program. Numerical examples are used to compare it with existing experimental data in a one dimensional case and to demonstrate the thermomechanical behavior of SMPs with 3D deformation. It is shown that the present constitutive theory and the finite element method can effectively simulate the… More >

D. Ho-Minh¹, N. Mai-Duy¹, T. Tran-Cong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.70, No.3, pp. 217-252, 2010, DOI:10.3970/cmes.2010.070.217

Abstract In this paper, one-dimensional integrated radial-basis-function networks (1D-IRBFNs) are introduced into the Galerkin and point-collocation formulations to simulate viscoelastic flows. The computational domain is represented by a Cartesian grid and IRBFNs, which are constructed through integration, are employed on each grid line to approximate the field variables including stresses in the streamfunction-vorticity formulation. Two types of fluid, namely Oldroyd-B and CEF models, are considered. The proposed methods are validated through the numerical simulation of several benchmark test problems including flows in a rectangular duct and in a corrugated tube. Numerical results show that accurate results are obtained using relatively-coarse grids. More >

C.-D. Tran¹, N. Mai-Duy^1,1, K. Le-Cao¹, T. Tran-Cong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.6, pp. 499-520, 2012, DOI:10.3970/cmes.2012.085.499

Abstract A numerical computation of continuum-microscopic model for visco-elastic flows based on the Integrated Radial Basis Function (IRBF) Control Volume and the Stochastic Simulation Techniques (SST) is reported in this paper. The macroscopic flow equations are closed by a stochastic equation for the extra stress at the microscopic level. The former are discretised by a 1D-IRBF-CV method while the latter is integrated with Euler explicit or Predictor-Corrector schemes. Modelling is very efficient as it is based on Cartesian grid, while the integrated RBF approach enhances both the stability of the procedure and the accuracy of the solution. The proposed method is… More >

M. Koyuncu¹, F. Y. Ikikat¹, G. C. Icoz², B. Baranoglu³, A. Yazici²

CMES-Computer Modeling in Engineering & Sciences, Vol.84, No.1, pp. 13-26, 2012, DOI:10.3970/cmes.2012.084.013

Abstract A parallel dual reciprocity boundary element method solution to thermoelasticity and thermoviscoelasticity problems is proposed. The DR-BEM formulation is given in Fourier Transform Space where the Time Space solutions are obtained through inverse Fourier Transform. The parallellization of the code is achieved through solving each frequency at a distinct computational node. The implemented parallel code is tested on 64-core IBM blade servers and it is seen that a linear speed-up is achieved. More >

C.-D. Tran¹, D.-A. An-Vo¹, N. Mai-Duy¹, T. Tran-Cong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.82, No.2, pp. 137-162, 2011, DOI:10.32604/cmes.2011.082.137

Abstract This paper presents a numerical approach for macro-micro multi-scale modelling of visco-elastic fluid flows based on the Integrated Radial Basis Function Networks (IRBFNs) and the Stochastic Simulation Technique (SST). The extra stress is calculated using the Brownian configuration fields (BCFs) technique while the velocity field is locally approximated at a set of collocation points using 1D-IRBFNs. In this approach, the stress is decoupled from the velocity field and computed from the molecular configuration directly without the need for a closed form rheological constitutive equation. The equations governing the macro flow field are discretised using a meshless collocation method where the… More >

D. C. C. Lam¹, L-H Keung¹, P. Tong²

CMES-Computer Modeling in Engineering & Sciences, Vol.66, No.1, pp. 73-100, 2010, DOI:10.3970/cmes.2010.066.073

Abstract Additional molecular rotations in long chained macromolecules lead to additional size dependence. In this investigation, we developed the higher order viscoelasticity framework and conducted experiments to determine the higher order material length scale parameters needed to describe the higher order viscoelastic behavior in the new framework. In the first part of the investigation of high order deformation behavior of macromolecular solids, the higher-order viscoelasticity theories for Maxwell and Kelvin-Voigt materials, and models of higher-order viscoelastic beam deflection creep are developed in this study. We conducted creep bending experiments with epoxy beams to show that the creep deflection behavior followed the… More >

Binxin Yang¹, Jie Ouyang¹, Tao Jiang¹, Chuntai Liu²

CMES-Computer Modeling in Engineering & Sciences, Vol.63, No.3, pp. 191-222, 2010, DOI:10.3970/cmes.2010.063.191

Abstract A gas-solid-liquid three-phase model is proposed for fiber reinforced composites mold filling process. The fluid flow is described in Eulerian coordinate while the dynamics of fibers is described in Langrangian coordinate. The interaction of fluid flow and fibers are enclosed in the model. The influence of fluid flow on fibers is described by the resultant forces imposed on fibers and the influence of fibers on fluid flow is described by the momentum exchange source term in the model. A finite volume method coupled with a level set method for viscoelastic-Newtonian fluid flow is used to solve the model. The direct… More >