Ruixiang Li^1,2, Yingying Liu³, Yaqiong Qiao^1,2, Te Ma^1,2, Bo Wang⁴, Xiangyang Luo^1,2,*

CMC-Computers, Materials & Continua, Vol.59, No.2, pp. 591-606, 2019, DOI:10.32604/cmc.2019.05208

Abstract High-density street-level reliable landmarks are one of the important foundations for street-level geolocation. However, the existing methods cannot obtain enough street-level landmarks in a short period of time. In this paper, a street-level landmarks acquisition method based on SVM (Support Vector Machine) classifiers is proposed. Firstly, the port detection results of IPs with known services are vectorized, and the vectorization results are used as an input of the SVM training. Then, the kernel function and penalty factor are adjusted for SVM classifiers training, and the optimal SVM classifiers are obtained. After that, the classifier sequence is constructed, and the IPs… More >

Khader M. Hamdia², Hamid Ghasemi³, Xiaoying Zhuang^4,5, Naif Alajlan¹, Timon Rabczuk^1,2,*

CMC-Computers, Materials & Continua, Vol.59, No.1, pp. 79-87, 2019, DOI:10.32604/cmc.2019.05882

Abstract In this study, machine learning representation is introduced to evaluate the flexoelectricity effect in truncated pyramid nanostructure under compression. A Non-Uniform Rational B-spline (NURBS) based IGA formulation is employed to model the flexoelectricity. We investigate 2D system with an isotropic linear elastic material under plane strain conditions discretized by 45×30 grid of B-spline elements. Six input parameters are selected to construct a deep neural network (DNN) model. They are the Young's modulus, two dielectric permittivity constants, the longitudinal and transversal flexoelectric coefficients and the order of the shape function. The outputs of interest are the strain in the stress direction… More >

Ligia Munteanu¹, Cornel Brisan², Veturia Chiroiu³, Stefania Donescu⁴

CMC-Computers, Materials & Continua, Vol.31, No.2, pp. 127-146, 2012, DOI:10.3970/cmc.2012.031.127

Abstract A modeling of the compression by using the property of Helmholtz equation to be invariant under geometric transformations is presented in this paper. The versatility of the geometric transformations is illustrated in order to obtain a new interpretation of the compression process. The physical spatial compression leads, most of the times, to new materials with inhomogeneous and anisotropic properties. The compression can be theoretically controlled by the geometric transformations. As an example, new architectures for auxetic materials can be built up by applying the geometric transformations. The new versions are finding their full correspondents in the results of the experiments… 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 >

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 >

Duraisamy Velmurugan¹, Masilamany Santha Alphin^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.2, pp. 125-141, 2018, DOI:10.31614/cmes.2018.01817

Abstract This study aims to investigate the effects of variable thread pitch on stress distribution in bones of different bone qualities under two different loading conditions (Vertical, and Horizontal) for a Zirconia dental implant. For this purpose, a three dimensional finite element model of the mandibular premolar section and three single threaded implants of 0.8 mm, 1.6 mm, 2.4 mm pitch was designed. Finite element analysis software was used to develop the model and three different bone qualities (Type II, Type III, and Type IV) were prepared. A vertical load of 200 N, and a horizontal load of 100 N was… More >

Sihan Chen¹, Bao Li¹, Haisheng Yang¹, Jianhang Du², Xiaoling Li², Youjun Liu^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.2, pp. 149-162, 2018, DOI: 10.31614/cmes.2018.04133

Abstract Enhanced external counterpulsation (EECP) is able to treat myocardial ischemia, which is usually caused by coronary artery stenosis. However, the underlying mechanisms regarding why this technique is effective in treating myocardial ischemia remains unclear and there is no patient-specific counterpulsation mode for different rates of coronary artery stenosis in clinic. This study sought to investigate the hemodynamic effect of varied coronary artery stenosis rates when using EECP and the necessity of adopting targeted counterpulsation mode to consider different rates of coronary artery stenosis. Three 3-dimensional (3D) coronary models with different stenosis rates, including 55% (Model 1), 65% (Model 2), and… More >

J.D. Turner¹ , A. Alnaqeb¹, A. Bani Younes¹

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.3, pp. 257-268, 2016, DOI:10.3970/cmes.2016.111.257

Abstract A singularity-free perturbation solution is presented for inverting the Cartesian to Geodetic transformation. Conventional approaches for inverting the transformation use the natural ellipsoidal coordinates, this work explores the use of the satellite ground-track vector as the differential correction variable. The geodetic latitude is recovered by well-known elementary means. A high-accuracy highperformance 3D vector-valued continued fraction iteration is constructed. Rapid convergence is achieved because the starting guess for the ground-track vector provides a maximum error of 30 m for the satellite height above the Earth's surface, throughout the LEO-GEO range of applications. As a result, a single iteration of the continued… More >

Mohammad Hossein Ghadiri Rad¹, Farzad Shahabian^1,2, Seyed Mahmoud Hosseini³

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.3, pp. 135-157, 2015, DOI:10.3970/cmes.2015.108.135

Abstract A meshless method based on the local Petrov-Galerkin approach is developed for elasto-dynamic analysis of geometrically nonlinear two dimensional (2D) problems in hyper-elastic functionally graded materials. The radial point interpolation method (RPIM) is utilized to build the shape functions and the Heaviside step function is used as the test function. The mechanical properties of functionally graded material are considered to continuously vary in a certain direction and are simulated using a nonlinear power function in volume fraction form. Considering the large deformations, it is assumed that the domain be made of large deformable neo-Hookean hyperelastic materials. Rayleigh damping is employed… More >

J. Wang^1,2, P. Simacek^1,2, S.G. Advani^1,2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.1, pp. 59-79, 2015, DOI:10.3970/cmes.2015.107.059

Abstract In Liquid Composite Molding (LCM) processes, resin is introduced into a stationary fiber reinforcement placed in the mold, until the reinforcement gets fully saturated with resin and all volatiles are vented out of the part. Finite element based software packages have been developed to simulate the mold filling process and eliminate expensive and tedious trial and error practices to arrive at a successful mold filling without any voids. However, the non-homogeneity of the fiber reinforcement material and its placement and layup in the mold creates a large degree of variability of flow patterns during the resin impregnation process. Executing simulations… More >