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EDITORIAL

Loc Vu-Quoc¹ and Shaofan Li²
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1075-1075, 2021, DOI:10.32604/cmes.2021.018780
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract This article has no abstract. More >

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EDITORIAL

Mark Austin, Thomas J.R. Hughes, Pamela Eibeck, Darryll Pines, Alice Agogino, J. Tinsley Oden, Lola Martin-Atilano, Billie Greene, Stein Sture, Constance Lütolf-Carroll, Ekkehard Ramm, Paula Hawthorn, Barbara Simons, Antoinette Torres, Carlos Felippa, Brant Smith, Peter Pinsky, Gary May, Sheila Humphreys, Loc Vu-Quoc
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1077-1122, 2021, DOI:10.32604/cmes.2021.018838
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract This article has no abstract. More >

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1141

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EDITORIAL

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1123-1123, 2021, DOI:10.32604/cmes.2021.019387
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract More >

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816

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ARTICLE

S. Morganti¹, F. Fahrendorf², L. De Lorenzis³, J. A. Evans⁴, T. J. R. Hughes^5,* and A. Reali⁶
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1125-1150, 2021, DOI:10.32604/cmes.2021.016832
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract We investigate primal and mixed u−p isogeometric collocation methods for application to nearly-incompressible isotropic elasticity. The primal method employs Navier’s equations in terms of the displacement unknowns, and the mixed method employs both displacement and pressure unknowns. As benchmarks for what might be considered acceptable accuracy, we employ constant-pressure Abaqus finite elements that are widely used in engineering applications. As a basis of comparisons, we present results for compressible elasticity. All the methods were completely satisfactory for the compressible case. However, results for low-degree primal methods exhibited displacement locking and in general deteriorated in the nearly-incompressible case. The results for… More >

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1119

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Mertcan Cihan, BlaŽ Hudobivnik, Fadi Aldakheel, Peter Wriggers^*
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1151-1180, 2021, DOI:10.32604/cmes.2021.016851
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract The virtual element method (VEM) can be seen as an extension of the classical finite element method (FEM) based on Galerkin projection. It allows meshes with highly irregular shaped elements, including concave shapes. So far the virtual element method has been applied to various engineering problems such as elasto-plasticity, multiphysics, damage and fracture mechanics. This work focuses on the extension of the virtual element method to efficient modeling of nonlinear elasto-dynamics undergoing large deformations. Within this framework, we employ low-order ansatz functions in two and three dimensions for elements that can have arbitrary polygonal shape. The formulations considered in this… More >

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1516

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Hiroki Akehashi, Izuru Takewaki^*
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1181-1207, 2021, DOI:10.32604/cmes.2021.017204
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract A new method of robust damper design is presented for elastic-plastic multi-degree-of-freedom (MDOF) building structures under multi-level ground motions (GMs). This method realizes a design that is effective for various levels of GMs. The robustness of a design is measured by an incremental dynamic analysis (IDA) curve and an ideal drift response curve (IDRC). The IDRC is a plot of the optimized maximum deformation under a constraint on the total damper quantity vs. the design level of the GMs. The total damper quantity corresponds to the total cost of the added dampers. First, a problem of generation of IDRCs is… More >

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Carlos A. Felippa^*
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1209-1241, 2021, DOI:10.32604/cmes.2021.016803
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract This paper considers Lagrangian finite elements for structural dynamics constructed with cubic displacement shape functions. The method of templates is used to investigate the construction of accurate mass-stiffness pairs. This method introduces free parameters that can be adjusted to customize elements according to accuracy and rank-sufficiency criteria. One- and two-dimensional Lagrangian cubic elements with only translational degrees of freedom (DOF) carry two additional nodes on each side, herein called side nodes or SN. Although usually placed at the third-points, the SN location may be adjusted within geometric limits. The adjustment effect is studied in detail using symbolic computations for a… More >

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867

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Magdalini Ntetsika, Panayiotis Papadopoulos^*
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1243-1258, 2021, DOI:10.32604/cmes.2021.017404
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract A new and computationally efficient version of the immersed boundary method, which is combined with the coarse-graining method, is introduced for modeling inextensible filaments immersed in low-Reynolds number flows. This is used to represent actin biopolymers, which are constituent elements of the cytoskeleton, a complex network-like structure that plays a fundamental role in shape morphology. An extension of the traditional immersed boundary method to include a stochastic stress tensor is also proposed in order to model the thermal fluctuations in the fluid at smaller scales. By way of validation, the response of a single, massless, inextensible semiflexible filament immersed in… More >

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1094

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Simon Martinez¹, Jürgen Lenz¹, Hans Schindler^1,2, Willi Wendler¹, Stefan Rues³, Karl Schweizerhof^1,*, Sophia Terebesi², Nikolaos Nikitas Giannakopoulos², Marc Schmitter²
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1259-1281, 2021, DOI:10.32604/cmes.2021.017422
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract The occlusal design plays a decisive role in the fabrication of dental restorations. Dentists and dental technicians depend on mechanical simulations of mandibular movement that are as accurate as possible, in particular, to produce interference-free yet chewing-efficient dental restorations. For this, kinetic data must be available, i.e., movements and deformations under the influence of forces and stresses. In the present study, so-called functional data were collected from healthy volunteers to provide consistent information for proper kinetics. For the latter purpose, biting and chewing forces, electrical muscle activity and jaw movements were registered synchronously, and individual magnetic resonance tomograms (MRI) were… More >

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1129

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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
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
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 >

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1083

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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
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
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 >

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1181

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Peter M. Pinsky^*
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1329-1350, 2021, DOI:10.32604/cmes.2021.017740
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
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 >

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1094

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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
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
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 >

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1679

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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
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
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 >

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1024

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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
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
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 >

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912

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Yuxi Xie, Shaofan Li^*
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1419-1440, 2021, DOI:10.32604/cmes.2021.016756
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
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 >

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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
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
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 >

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1333

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CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1487-1488, 2021, DOI:10.32604/cmes.2021.019388
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract This article has no abstract. More >

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1651

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1106

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CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1489-1504, 2021, DOI:10.32604/cmes.2021.019434
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract This article has no abstract. More >

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1646

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1134

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CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1505-1522, 2021, DOI:10.32604/cmes.2021.019500
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract This article has no abstract. More >

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1615

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1257

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EDITORIAL

Mark Austin, Loc Vu-Quoc
CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1523-1529, 2021, DOI:10.32604/cmes.2021.019683
（This article belongs to this Special Issue: Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister)
Abstract This article has no abstract. More >

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1172