CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1489-1504, 2021, DOI:10.32604/cmes.2021.019434

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CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1487-1488, 2021, DOI:10.32604/cmes.2021.019388

Abstract This article has no abstract. More >

Loc Vu-Quoc^1,*, Yuhu Zhai² and Khai D. T. Ngo³

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1441-1486, 2021, DOI:10.32604/cmes.2021.016784

Abstract The Generalized Falk Method (GFM) for coordinate transformation, together with two model-reduction strategies based on this method, are presented for efficient coupled field-circuit simulations. Each model-reduction strategy is based on a decision to retain specific linearly-independent vectors, called trial vectors, to construct a vector basis for coordinate transformation. The reduced-order models are guaranteed to be stable and passive since the GFM is a congruence transformation of originally symmetric positive definite systems. We also show that, unlike the Pad´e-via-Lanczos (PVL) method, the GFM does not generate unstable positive poles while reducing the order of circuit problems. Further, the proposed GFM is… More >

Yuxi Xie, Shaofan Li^*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1419-1440, 2021, DOI:10.32604/cmes.2021.016756

Abstract The microstructure of crystal defects, e.g., dislocation patterns, are not arbitrary, and it is possible that some of them may be related to the microstructure of crystals itself, i.e., the lattice structure. We call those dislocation patterns or substructures that are related to the corresponding crystal microstructure as the Geometrically Compatible Dislocation Patterns (GCDP). Based on this notion, we have developed a Multiscale Crystal Defect Dynamics (MCDD) to model crystal plasticity without or with minimum empiricism. In this work, we employ the multiscale dislocation pattern dynamics, i.e., MCDD, to simulate crystal plasticity in body-centered cubic (BCC) single crystals, mainly α-phase… More >

Alexander Humer and Hans Irschik^*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1395-1417, 2021, DOI:10.32604/cmes.2021.017944

Abstract This paper addresses the application of the continuum mechanics-based multiplicative decomposition for thermohyperelastic materials by Lu and Pister to Reissner’s structural mechanics-based, geometrically exact theory for finite strain plane deformations of beams, which represents a geometrically consistent non-linear extension of the linear shear-deformable Timoshenko beam theory. First, the Lu-Pister multiplicative decomposition of the displacement gradient tensor is reviewed in a three-dimensional setting, and the importance of its main consequence is emphasized, i.e., the fact that isothermal experiments conducted over a range of constant reference temperatures are sufficient to identify constitutive material parameters in the stress-strain relations. We address various isothermal… More >

Matthew Wilkinson, Javier Villarreal, Andrew Meade^*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1373-1393, 2021, DOI:10.32604/cmes.2021.017883

Abstract A meshless and matrix-free fluid dynamics solver (SOMA) is introduced that avoids the need for user generated and/or analyzed grids, volumes, and meshes. Incremental building of the approximation avoids creation and inversion of possibly dense block diagonal matrices and significantly reduces user interaction. Validation results are presented from the application of SOMA to subsonic, compressible, and turbulent flow over an adiabatic flat plate. More >

Ye Lu¹, Hengyang Li¹, Sourav Saha², Satyajit Mojumder², Abdullah Al Amin¹, Derick Suarez¹, Yingjian Liu³, Dong Qian³, Wing Kam Liu^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1351-1371, 2021, DOI:10.32604/cmes.2021.017719

Abstract This paper presents the concept of reduced order machine learning finite element (FE) method. In particular, we propose an example of such method, the proper generalized decomposition (PGD) reduced hierarchical deeplearning neural networks (HiDeNN), called HiDeNN-PGD. We described first the HiDeNN interface seamlessly with the current commercial and open source FE codes. The proposed reduced order method can reduce significantly the degrees of freedom for machine learning and physics based modeling and is able to deal with high dimensional problems. This method is found more accurate than conventional finite element methods with a small portion of degrees of freedom. Different… More >

Peter M. Pinsky^*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1329-1350, 2021, DOI:10.32604/cmes.2021.017740

Abstract A fundamental problem for cells with their fragile membranes is the control of their volume. The primordial solution to this problem is the active transport of ions across the cell membrane to modulate the intracellular osmotic pressure. In this work, a theoretical model of the cellular pump-leak mechanism is proposed within the general framework of linear nonequilibrium thermodynamics. The model is expressed with phenomenological equations that describe passive and active ionic transport across cell membranes, supplemented by an equation for the membrane potential that accounts for the electrogenicity of the ionic pumps. For active ionic transport, the model predicts that… More >

Yu-Fu Ko^1,* , Jiann-Wen Woody Ju²

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1305-1328, 2021, DOI:10.32604/cmes.2021.017589

Abstract Higher-order multiscale structures are proposed to predict the effective elastic properties of 3-phase particle reinforced composites by considering the probabilistic spherical particles spatial distribution, the particle interactions, and utilizing homogenization with ensemble volume average approach. The matrix material, spherical particles with radius a₁, and spherical particles with radius a₂, are denoted as the 0^th phase, the 1^st phase, and the 2^nd phase, respectively. Particularly, the two inhomogeneity phases are different particle sizes and the same elastic material properties. Improved higher-order (in ratio of spherical particle sizes to the distance between the centers of spherical particles) bounds on effective elastic properties… More >

Arash Mehraban¹, Henry Tufo¹, Stein Sture², Richard Regueiro^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1283-1303, 2021, DOI:10.32604/cmes.2021.017476

Abstract Higher-order displacement-based finite element methods are useful for simulating bending problems and potentially addressing mesh-locking associated with nearly-incompressible elasticity, yet are computationally expensive. To address the computational expense, the paper presents a matrix-free, displacement-based, higher-order, hexahedral finite element implementation of compressible and nearly-compressible (ν → 0.5) linear isotropic elasticity at small strain with p-multigrid preconditioning. The cost, solve time, and scalability of the implementation with respect to strain energy error are investigated for polynomial order p = 1, 2, 3, 4 for compressible elasticity, and p = 2, 3, 4 for nearly-incompressible elasticity, on different number of CPU cores for… More >