P. Raghavan¹, S. Ghosh²

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.2, pp. 151-170, 2004, DOI:10.3970/cmes.2004.005.151

Abstract This paper presents an adaptive multi-level computational model that combines a conventional displacement based finite element model with a microstructural Voronoi cell finite element model for multi-scale analysis of composite structures with non-uniform microstructural heterogeneities as obtained from optical or scanning electron micrographs. Three levels of hierarchy, with different resolutions, are introduced in this model to overcome shortcomings posed by modeling and discretization errors. Among the three levels are: (a) level-0 of pure macroscopic analysis; (b) level-1 of macro-micro coupled modeling, used for signaling the switch over from macroscopic analyses to pure microscopic analyses; and (c) level-2 regions of pure… More >

Molecular & Cellular Biomechanics, Vol.9, No.1, pp. 77-94, 2012, DOI:10.3970/mcb.2012.009.077

Abstract Image-based computational modeling has been introduced for vulnerable atherosclerotic plaques to identify critical mechanical conditions which may be used for better plaque assessment and rupture predictions. In vivo patient-specific coronary plaque models are lagging due to limitations on non-invasive image resolution, flow data, and vessel material properties. A framework is proposed to combine intravascular ultrasound (IVUS) imaging, biaxial mechanical testing and computational modeling with fluid-structure interactions and anisotropic material properties to acquire better and more complete plaque data and make more accurate plaque vulnerability assessment and predictions. Impact of pre-shrink-stretch process, vessel curvature and high blood pressure on stress, strain,… More >

Chun Yang^∗,†, Dalin Tang^∗,‡, Shunichi Kobayashi^§, Jie Zheng^¶, Pamela K. Woodard^§, Zhongzhao Teng^*, Richard Bach^||, David N. Ku^∗∗

Molecular & Cellular Biomechanics, Vol.5, No.4, pp. 259-274, 2008, DOI:10.3970/mcb.2008.005.259

Abstract Many acute cardiovascular syndromes such as heart attack and stroke are caused by atherosclerotic plaque ruptures which often happen without warning. MRI-based models with fluid-structure interactions (FSI) have been introduced to perform flow and stress/strain analysis for atherosclerotic plaques and identify possible mechanical and morphological indices for accurate plaque vulnerability assessment. In this paper, cyclic bending was added to 3D FSI coronary plaque models for more accurate mechanical predictions. Curvature variation was prescribed using the data of a human left anterior descending (LAD) coronary artery. Five computational models were constructed based on ex vivo MRI human coronary plaque data to… More >

Zhijian Qiu¹, Jinchi Lu¹, Ahmed Elgamal^1,*, Lei Su², Ning Wang³, Abdullah Almutairi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 629-656, 2019, DOI:10.32604/cmes.2019.05759

Abstract The OpenSees computational platform has allowed unprecedented opportunities for conducting seismic nonlinear soil-structure interaction simulations. On the geotechnical side, capabilities such as coupled solid-fluid formulations and nonlinear incremental-plasticity approaches allow for representation of the involved dynamic/seismic responses. This paper presents recent research that facilitated such endeavors in terms of response of ground-foundation-structure systems using advanced material modeling techniques and high-performance computing resources. Representative numerical results are shown for large-scale soil-structure systems, and ground modification liquefaction countermeasures. In addition, graphical user interface enabling tools for routine usage of such 3D simulation environments are presented, as an important element in support of… More >

Chang-Chun Lee^1,*, Pei-Chen Huang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 239-260, 2019, DOI:10.32604/cmes.2019.06859

Abstract This research reviews the application of computational mechanics on the properties of nano/micro scaled thin films, in which the application of different computational methods is included. The concept and fundamental theories of concerned applications, material behavior estimations, interfacial delamination behavior, strain engineering, and multilevel modeling are thoroughly discussed. Moreover, an example of an interfacial adhesion estimation is presented to systematically estimate the related mechanical reliability issue in the microelectronic industry. The presented results show that the peeled mode fracture is the dominant delamination behavior of layered material system, with high stiffness along the bonding interface. However, the shear mode fracture… More >

John D. Clayton^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 333-350, 2019, DOI:10.32604/cmes.2019.06342

Abstract A theory invoking concepts from differential geometry of generalized Finsler space in conjunction with diffuse interface modeling is described and implemented in finite element (FE) simulations of dual-phase polycrystalline ceramic microstructures. Order parameters accounting for fracture and other structural transformations, notably partial dislocation slip, twinning, or phase changes, are dimensionless entries of an internal state vector of generalized pseudo-Finsler space. Ceramics investigated in computations are a boron carbide-titanium diboride (B₄C-TiB₂) composite and a diamond-silicon carbide (C-SiC) composite. Deformation mechanisms-in addition to elasticity and cleavage fracture in grains of any phase-include restricted dislocation glide (TiB₂ phase), deformation twinning (B₄C and β-SiC… More >

T.I. Zohdi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.3, pp. 261-277, 2014, DOI:10.32604/cmes.2014.098.261

Abstract A widespread use of lasers is for the ablation of biological tissue, in particular for dermal applications involving the removal of cancerous tissue, skin spots, aged skin and wrinkles. For a laser to ablate tissue, the power intensity must be sufficiently high to induce vaporization/burning of the target material. However, if performed improperly, the process can cause excessive microscale thermal injuries to surrounding healthy tissue. This motivates the present work, which attempts to develop and assemble simple models for the primary heat transfer mechanisms that occur during the process. First, in order to qualitatively understand the system, the terms that… More >

K. Lee¹, C.T. Wu², G.V. Clarke³, S.W. Lee⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.33, No.1, pp. 109-130, 2008, DOI:10.3970/cmes.2008.033.109

Abstract A geometrically nonlinear finite element analysis of a low areal density composite space reflector is conducted under static conditions and the results are compared with independently carried out experimental data. The finite element analysis is based on an assumed strain formulation of a geometrically nonlinear nine-node solid shell element. Numerical results are in good agreement with experimental data. This demonstrates the effectiveness of the present solid shell element approach when applied to the analysis of highly flexible space structures. The results of numerical analysis and the experimental data reported in the present paper provide a benchmark for future investigations on… More >

A. M. Rajendran¹, D. J. Grove²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.3, pp. 367-380, 2002, DOI:10.3970/cmes.2002.003.367

Abstract This paper presents detailed computational analyses investigating the ability of constitutive relationships to describe the response of a 99.5% pure alumina (AD995) subjected to a wide range of stress/strain loading states. Using a shock-wave-propagation-based finite element code, one and two-dimensional simulations were performed for the following shock and impact configurations: plate-on-plate impact; rod-on-rod impact; single-density plate-on-rod impact; graded-density plate-on-rod impact; and rod penetration into a thick plate. The detailed analyses presented in this paper include a model constant sensitivity study through comparisons of computed wave profiles with experimental measurements. 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 a random manner for the… More >