Dongwoo Sohn¹, Jae Hyuk Lim², Young-Sam Cho³, Seyoung Im¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.10, No.2, pp. 53-54, 2009, DOI:10.3970/icces.2009.010.053

Abstract A novel multiscale finite element (FE) scheme is proposed for a simulation of crack propagation in the heterogeneous media including randomly distributed microstructures, such as voids, rigid fibers. A fine scale mesh is employed to capture the singularity of the crack tip and the effect of microstructures at the vicinity of crack tip. On the other hand, a region far from the crack tip is composed of coarse scale mesh, wherein the effect of the microstructures is averaged through the homogenization theory. An interface between the fine scale mesh and the coarse scale mesh is connected by variable-node finite elements… More >

Mikhail Itskov*, Khiȇm Ngoc Vu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.1, pp. 112-112, 2019, DOI:10.32604/icces.2019.05013

Abstract Mechanoluminescence is a phenomenon where broken chemical bonds send out visible light upon stress application. To this end, special mechanophores are added into the polymer network prior to its vulcanization. As such, bis(adamantyl) 1,2-dioxetane can be used. The breakage of the dioxetane cross-linker is irreversible and can directly be used to assess the damage evolution in rubber-like materials. The intensity of the emitted light correlates with the underlying evolution of chain scission in polymers. In this contribution, an anisotropic analytical network-averaging concept [1] is utilized to model mechanoluminescence, Mullins effect, hysteresis and induced anisotropy in mechano-chemically responsive polymeric materials [2].… More >

K.G. Wang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 21-28, 2007, DOI:10.3970/icces.2007.003.021

Abstract A framework of applications of multiscale modeling to property prediction of advanced materials will be briefly presented. A methodology will be shown to link micro-scale to the continuum scale, integrating micro-scale modeling of microstructure with the large Thermo-Calc© database. This paradigm is successfully applied to the case of Fe-12Ni-6Mn maraging steel. We predict the mechanical properties of the maraging steel such as hardness. We found that our predictions in hardness is in agreement with experimental data. More >

S.P. Xiao¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 15-20, 2007, DOI:10.3970/icces.2007.003.015

Abstract A bridging domain method for coupling continuum models with molecular models is described. In this method, the continuum and molecular domains are overlapped in a bridging subdomain, where the Hamiltonian is taken to be a linear combination of the continuum and molecular Hamiltonians. We enforce the compatibility in the bridging domain by Lagrange multipliers or by the augmented Lagrangian method. An explicit algorithm for dynamic solutions is developed. In this paper, the bridging domain multiscale method is employed to study nanotube-based composites. More >

Philippe Devloo¹, Wenchao Teng², Chen-Song Zhang^3,∗

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 145-163, 2019, DOI:10.32604/cmes.2019.04812

Abstract The multiscale hybrid-mixed (MHM) method is applied to the numerical approximation of two-dimensional matrix fluid flow in porous media with fractures. The two-dimensional fluid flow in the reservoir and the one-dimensional flow in the discrete fractures are approximated using mixed finite elements. The coupling of the two-dimensional matrix flow with the one-dimensional fracture flow is enforced using the pressure of the one-dimensional flow as a Lagrange multiplier to express the conservation of fluid transfer between the fracture flow and the divergence of the one-dimensional fracture flux. A zero-dimensional pressure (point element) is used to express conservation of mass where fractures… More >

Hiroshi Kadowaki¹, Wing Kam Liu²

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.3, pp. 269-282, 2005, DOI:10.3970/cmes.2005.007.269

Abstract A method to derive governing equations and elastic-plastic constitutive relations for the micropolar continuum model is proposed. Averaging procedures are operated over a surrounding sub-domain for each material point to bridge a discrete microstructure to a macro continuum model. Material parameters are determined by these procedures. The size of the sub-domain represents the material intrinsic length scale, and it is passed into the macroscopic governing equation so that the numerical solution can be regularized for analyses of failure phenomena. An application to a simple granular material model is presented. More >

Shengping Shen¹, S. N. Atluri¹

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.1, pp. 49-68, 2005, DOI:10.3970/cmes.2005.007.049

Abstract The main objective of this paper is to develop a multiscale method for the static analysis of a nano-system, based on a combination of molecular mechanics and MLPG methods. The tangent-stiffness formulations are given for this multiscale method, as well as a pure molecular mechanics method. This method is also shown to naturally link the continuum local balance equation with molecular mechanics, directly, based on the stress or force. Numerical results show that this multiscale method quite accurate. The tangent-stiffness MLPG method is very effective and stable in multiscale simulations. This multiscale method dramatically reduces the computational cost, but it… More >

gping Shen¹, S. N. Atluri¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.3, pp. 235-256, 2004, DOI:10.3970/cmes.2004.005.235

Abstract A multiscale simulation technique based on the MLPG methods, and finite deformation mechanics, is developed, implemented, and tested. Several alternate time-dependent interfacial conditions, between the atomistic and continuum regions, are systematically studied, for the seamless multiscale simulation, by decomposing the displacement of atoms in the equivalent-continuum region into long and short wave-length components. All of these methods for enforcing the interface conditions can ensure the passage of information accurately between the atomistic and continuum regions, while they lead to different performances at short wavelengths. The presently proposed Solution Method 2 reduces the phonon reflections at the interface, without increasing the… More >

Peter W. Chung¹, Raju R. Namburu², Brian J. Henz³

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 45-62, 2004, DOI:10.3970/cmes.2004.005.045

Abstract A method is developed based on an additive modification to the first Lagrangian elasticity tensor to make the finite element method for hyperelasticity viable at the atomic length scale in the context of lattice statics. Through the definition of an overlap region, the close-ranged atomic interaction energies are consistently summed over the boundary of each finite element. These energies are subsequently used to additively modify the conventional material property tensor that comes from the second derivative of the stored energy function. The summation over element boundaries, as opposed to atom clusters, allows the mesh and nodes to be defined independently… More >

Angran Li¹, Xiaoqi Chai², Ge Yang^2,3, Yongjie Jessica Zhang^1,2,*

Molecular & Cellular Biomechanics, Vol.16, No.2, pp. 123-140, 2019, DOI:10.32604/mcb.2019.06479

Abstract Neurons exhibit remarkably complex geometry in their neurite networks. So far, how materials are transported in the complex geometry for survival and function of neurons remains an unanswered question. Answering this question is fundamental to understanding the physiology and disease of neurons. Here, we have developed an isogeometric analysis (IGA) based platform for material transport simulation in neurite networks. We modeled the transport process by reaction-diffusion-transport equations and represented geometry of the networks using truncated hierarchical tricubic B-splines (THB-spline3D). We solved the Navier-Stokes equations to obtain the velocity field of material transport in the networks. We then solved the transport… More >