L. Dong¹, S. N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.81, No.1, pp. 69-118, 2011, DOI:10.3970/cmes.2011.081.069

Abstract In this paper, we explore three different ways of developing T-Trefftz finite elements of quadrilateral as well as polygonal shapes. In all of these three approaches, in addition to assuming an inter-element compatible displacement field along the element boundary, an interior displacement field for each element is independently assumed as a linear combination of T-Trefftz trial functions. In addition, a characteristic length is defined for each element to scale the T-Trefftz modes, in order to avoid solving systems of ill-conditioned equations. The differences between these three approaches are that, the compatibility between the independently assumed… More >

I. Pérez¹, R. Roselló¹, C. Recarey¹, M. Cerrolaza²

CMES-Computer Modeling in Engineering & Sciences, Vol.79, No.3&4, pp. 183-200, 2011, DOI:10.3970/cmes.2011.079.183

Abstract Modeling the geometry and behavior of human bones is of the most concern when dealing with bone remodelling (external and internal) and poroelastic analysis. Complex geometries are frequently found in the human skeleton as well as orthotropic behavior of bone tissue. Spongy bone has a completely different constitution as compared with compact bone, which adds another relevant consideration if we want to get reliable results in biomechanical analysis. The modeling of both compact and spongy human-bone tissue is carried out by using packaging-particle methods. The methods generate circles (2D domains) and spheres (3D domains) in More >

A.B. Tatomir^1,2, A.Szymkiewicz³, H. Class¹, R. Helmig¹

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.2, pp. 81-112, 2011, DOI:10.3970/cmes.2011.077.081

Abstract We present a two phase flow conceptual model, the corresponding simulator (2pMINC) and a workflow for large-scale fractured reservoirs, based on a continuum fracture approach which uses the multiple interacting continua (MINC) method complemented with an improved upscaling technique. The complex transient behavior of the flow processes in fractured porous media is captured by subgridding the coarse blocks in nested volume elements which have effective properties calculated from the detailed representation of the fracture system. In this way, we keep a physically based approach, preserve the accuracy of the model, avoid the common use of… More >

Xiaowei Zeng¹

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.3&4, pp. 183-202, 2011, DOI:10.3970/cmes.2011.074.183

Abstract This paper presents an atomistic field theory and its application in modeling and simulation of nano/micro materials. Atomistic formulation and finite element implementation of the atomistic field theory is briefly introduced. Numerical simulations based on the field theory are performed to investigate the material behaviors of bcc iron at coarse-grained scale and we have obtained the mechanical strength and elastic modulus, which are in good agreement with results by first principles calculations. Also the nanoscale deformation and failure mechanism are revealed in bcc iron nanorods under simple tension. It is interesting to observe that under More >

A. Gakwaya¹, H. Sharifi², M. Guillot¹, M. Souli³, F. Erchiqui⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.3, pp. 209-266, 2011, DOI:10.3970/cmes.2011.073.209

Abstract A mechanical computer aided design and engineering system can be used to reduce the design-to-manufacture cycle time in metal forming process. Such a system could be built upon a solid modeling geometry engine and an efficient finite element (FE) solver. The maintenance of a high-quality mesh throughout the analysis is an essential feature of an efficient finite element simulation of large strain metal forming problems. In this paper, a mesh adaptation technique employing the Arbitrary Lagrangian-Eulerian formulation (ALE) is applied to some industrial metal forming problems. An ACIS boundary representation of the solid model is… More >

Duning Li¹, Yufeng Nie^1,2, Xuemei Zhou¹, Li Cai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.2, pp. 149-166, 2011, DOI:10.3970/cmes.2011.072.149

Abstract In this study, the efficient discrete model including the resin infusion and the fiber compaction is developed to simulate the RFI (resin film infusion) process. The non-linear governing equations are derived by the Darcy's law, the Terzaghi's law and the continuity equations. The finite element method and the finite difference method are used to discretize the proposed equations, and the VOF method is used to track the filling front. Compared with the analytical results of Park, our numerical results agree well with them. Furthermore, we analyze the RFI process of BMI/G0814, and simulate the resin More >

Robert Rundqvist¹, Andreas Mark¹, Fredrik Edelvik¹, Johan S. Carlsson¹

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.3, pp. 259-278, 2011, DOI:10.3970/fdmp.2011.007.259

Abstract Multiphase flow simulation using Smoothed Particle Hydrodynamics (SPH) has gained interest during recent years, mostly due to the inherent flexibility of the method and the physically rather intuitive formulation of extra constitutive equations needed when dealing with for instance non-Newtonian flows. In the work presented here, simulations based on an SPH model implemented in the flow solver IBOFlow has been used for simulation of robotic application of sealing material on a car body. Application of sealing materials is done in order to prevent water leakage into cavities of the body, and to reduce noise. In… More >

A. Bakkali¹, L. Azrar^1,2, N. Fakri¹

CMC-Computers, Materials & Continua, Vol.23, No.3, pp. 201-232, 2011, DOI:10.3970/cmc.2011.023.201

Abstract In this paper an N-phase Incremental Self Consistent model is developed for magnetoelectroelastic composites as well as the N-phase Mori-Tanaka and classical Self Consistent. Our aim here is to circumvent the limitation of the Self Consistent predictions for some coupling effective properties at certain inclusion volume fractions. The anomalies of the SC estimates are more drastic when the void inclusions are considered. The mathematical modeling is based on the heterogeneous inclusion problem of Eshelby which leads to an expression for the strain-electric-magnetic field related by integral equations. The effective N-phase magnetoelectroelastic moduli are expressed as More >

Bengt Sundén^*, Jinliang Yuan

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-20, 2010, DOI:10.5098/hmt.v1.1.3008

Abstract Depending on specific configuration and design, a variety of physical phenomena is present in fuel cells, e.g., multi-component gas flow, energy and mass transfer of chemical species in composite domains and sites. These physical phenomena are strongly affected by chemical/electrochemical reactions in nano-/micro-scale structured electrodes and electrolytes. Due to the electrochemical reactions, generation and consumption of chemical species together with electric current production take place at the active surfaces for all kinds of fuel cells. Furthermore, water management and twophase flow in proton exchange membrane fuel cells (PEMFCs) and internal reforming reactions of hydrocarbon fuels More >

Po Ting Lin, Hae Chang Gea, Yogesh Jaluria^*

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-20, 2010, DOI:10.5098/hmt.v1.1.3003

Abstract Thermal systems play significant roles in the engineering practice and our lives. To improve those thermal systems, it is necessary to model and optimize the design and the operating conditions. More importantly, the design uncertainties should be considered because the failures of the thermal systems may be very dangerous and produce large loss. This review paper focuses on a systematic strategy of modeling and optimizing of the thermal systems with the considerations of the design uncertainties. To demonstrate the proposed strategy, one of the complicated thermal systems, Chemical Vapor Deposition (CVD), is simulated, parametrically modeled,… More >