F. S. Tabatabaei^∗, M. Jazayeri^†, P. Ghahari^‡, N. Haghighipour^§

Molecular & Cellular Biomechanics, Vol.11, No.3, pp. 209-220, 2014, DOI:10.3970/mcb.2014.011.209

Abstract During orthodontic treatments, applied mechanical forces create strain and result in tooth movement through the alveolar bone. This response to mechanical strain is a fundamental biological reaction. The present study evaluated the effect of equiaxial strain within the range of orthodontic forces on the osteogenic differentiation of human dental pulp stem cells (hDPSCs). Following isolation and culture of hDPSCs, 3rd passage cells were transferred on a silicone membrane covered with collagen. Cell adhesion to the membrane was evaluated under scanning electron microscope (SEM). Cells were divided into three groups: the first group was placed in… More >

Rui Fan¹, Dalin Tang^2,3, Jing Yao⁴, Chun Yang⁵, Di Xu⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.6, pp. 491-508, 2014, DOI:10.3970/cmes.2014.099.491

Abstract Identifying ventricle material properties and its infarct area after heart attack noninvasively is of great important in clinical applications. An echo-based computational modeling approach was proposed to investigate left ventricle (LV) mechanical properties and stress conditions using patient-specific data. Echo data was acquired from one healthy volunteer (male, age: 58) and a male patient (age: 60) who had an acute inferior myocardial infarction one week before echo image acquisition. Standard echocardiograms were obtained using an ultrasound machine (E9, GE Mechanical Systems, Milwaukee, Wisconsin) with a 3V probe and data were segmented for model construction. Finite… More >

Chein-Shan Liu ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.5, pp. 371-391, 2014, DOI:10.3970/cmes.2014.099.371

Abstract We recover an unknown initial temperature for a nonlinear heat conduction equation u_t(x,t) = u_xx(x,t) + H(x,t,u,u_x), under the Cauchy boundary conditions specified on the left-boundary. The method in the present paper transforms the Cauchy problem into an inverse heat source problem to find F(x) in T_t(x,t) = T_xx(x,t) + H + F(x). By using the GL(N,R) Lie-group differential algebraic equations (LGDAE) algorithm to integrate the numerical method of lines discretized equations from sideways heat equation, we can fast recover the initial temperature and two boundary conditions on the right-boundary. The accuracy and efficiency are confirmed by comparing the More >

S.Yu. Reutskiy¹

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.4, pp. 327-349, 2014, DOI:10.3970/cmes.2014.099.327

Abstract The paper presents a new meshless numerical method for solving 2D and 3D boundary value problems (BVPs) with elliptic PDEs of general form. The coefficients of the PDEs including the main operator part are spatially dependent functions. The key idea of the method is the use of the basis functions which satisfy the homogeneous boundary conditions of the problem. This allows us to seek an approximate solution in the form which satisfies the boundary conditions of the initial problem with any choice of the free parameters. As a result we separate approximation of the boundary More >

Yong-Lin Pi¹, Mark Andrew Bradford¹

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.3, pp. 233-253, 2014, DOI:10.3970/cmes.2014.099.233

Abstract Creep and shrinkage of the concrete core of a concrete-filled steel tubular (CFST) arch under sustained loading are inevitable, and cause a long-term change of the equilibrium configuration of the CFST arch. As the equilibrium configuration changes continuously, the long-term radial and axial displacements of the CFST arch, stress distributions as well as the internal forces in the steel tube and the concrete core change substantially with time. Creep and shrinkage of the concrete core are related to a number of its material parameters such as its creep coefficient, aging coefficient, and shrinkage strain. The… More >

Weichung Yeih^1,2, I-Yao Chan¹, Cheng-Yu Ku¹, Chia-Ming Fan¹, Pai-Chen Guan³

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.2, pp. 123-149, 2014, DOI:10.3970/cmes.2014.099.123

Abstract In this paper, a novel double iteration process for solving the nonlinear algebraic equations is developed. In this process, the outer iteration controls the evolution path of the unknown vector x in the selected direction u which is determined from the inner iteration process. For the inner iteration, the direction of evolution u is determined by solving a linear algebraic equation: B^TBu = B^TF where B is the Jacobian matrix, F is the residual vector and the superscript ''T'' denotes the matrix transpose. For an ill-posed system, this linear algebraic equation is very difficult to solve since the resulting… More >

T.A. Elgohary¹, L. Dong², J.L. Junkins³, S.N. Atluri⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.6, pp. 543-563, 2014, DOI:10.3970/cmes.2014.098.543

Abstract In this study, the Scalar Homotopy Methods are applied to the solution of post-buckling and limit load problems of solids and structures, as exemplified by simple plane elastic frames, considering only geometrical nonlinearities. Explicitly derived tangent stiffness matrices and nodal forces of large-deformation planar beam elements, with two translational and one rotational degrees of freedom at each node, are adopted following the work of [Kondoh and Atluri (1986)]. By using the Scalar Homotopy Methods, the displacements of the equilibrium state are iteratively solved for, without inverting the Jacobian (tangent stiffness) matrix. It is well-known that,… More >

Cheng-Yu Ku ^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.5, pp. 509-541, 2014, DOI:10.3970/cmes.2014.098.509

Abstract This paper proposes the numerical solution of three-dimensional Laplacian problems in a multiply connected domain using the collocation Trefftz method with multiple source points. A numerical solution for three-dimensional Laplacian problems was approximated by superpositioning T-complete functions formulated from 36 independent functions satisfying the governing equation in the cylindrical coordinate system. To deal with complicated problems for multiply connected domain, we adopted the generalized multiple source point boundary collocation Trefftz method which allows many source points in the Trefftz formulation without using the decomposition of the problem domain. In addition, to mitigate a severely ill-conditioned More >

C. Jiang^1,2, S. Yu¹, H.C. Xie¹, B.C. Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.4, pp. 443-467, 2014, DOI:10.3970/cmes.2014.098.443

Abstract Based on the interval analysis method, this paper proposes an uncertain optimization model for the ride comfort in vehicles and achieves the optimal design of vehicle ride comfort under the condition of complicated uncertainty. The spring stiffness and shock absorber damping of suspension is regarded as the design parameters, while the root mean square (RMS) of the vehicle body acceleration is treated as the design objective and the corresponding constraints are composed of suspension stiffness, natural frequency and RMS of suspension dynamic deflection. Moreover, the uncertainties of key parameters, such as sprung mass, tire stiffness, More >

Chu Wang, Lucy T. Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.1, pp. 41-67, 2014, DOI:10.3970/cmes.2014.098.041

Abstract Bloodstain pattern analysis (BPA) in forensic science is an important tool to solve crime scenes. The complex dynamic behavior of blood drops poses great challenges for accurate fluid dynamic simulations. In this paper, we specifically focus on simulations of blood drop spreading and impact, which may involve contact line hysteresis and spattering of drops as they interact with solid surfaces. Here, we set up a numerical framework that combines (1) the connectivity-free front tracking (CFFT) method for modeling multiphase (air and liquid) flows and (2) a dynamic contact line model for modeling fluid-solid contact line.… More >