Zhilin Li^1,∗, Baiying Dong², Fenghua Tong³, Weilong Wang³

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 63-72, 2019, DOI:10.32604/cmes.2019.04635

Abstract The immersed boundary method is well-known, popular, and has had vast areas of applications due to its simplicity and robustness even though it is only first order accurate near the interface. In this paper, an immersed boundary-augmented method has been developed for linear elliptic boundary value problems on arbitrary domains (exterior or interior) with a Dirichlet boundary condition. The new method inherits the simplicity, robustness, and first order convergence of the IB method but also provides asymptotic first order convergence of partial derivatives. Numerical examples are provided to confirm the analysis. More >

Andrew Lundberg¹, Pengtao Sun^1,∗, Cheng Wang², Chen-song Zhang³

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 35-62, 2019, DOI:10.32604/cmes.2019.04804

Abstract The distributed Lagrange multiplier/fictitious domain (DLM/FD)-mixed finite element method is developed and analyzed in this paper for a transient Stokes interface problem with jump coefficients. The semi- and fully discrete DLM/FD-mixed finite element scheme are developed for the first time for this problem with a moving interface, where the arbitrary Lagrangian-Eulerian (ALE) technique is employed to deal with the moving and immersed subdomain. Stability and optimal convergence properties are obtained for both schemes. Numerical experiments are carried out for different scenarios of jump coefficients, and all theoretical results are validated. More >

X.Sheldon Wang^1,∗, Ye Yang², Tao Wu²

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 5-34, 2019, DOI:10.32604/cmes.2019.04204

Abstract In this work, we employ fluid-structure interaction (FSI) systems with immersed flexible structures with or without free surfaces to explore both Singular Value Decomposition (SVD)-based model reduction methods and mode superposition methods. For acoustoelastic FSI systems, we adopt a three-field mixed finite element formulation with displacement, pressure, and vorticity moment unknowns to effectively enforce the irrotationality constraint. We also propose in this paper a new Inf-Sup test based on the lowest non-zero singular value of the coupling matrix for the selection of reliable sets of finite element discretizations for displacement and pressure as well as… More >

Zhilin Li¹, X.Sheldon Wang^{2, ∗}, LucyT. Zhang³

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 1-3, 2019, DOI:10.32604/cmes.2019.06635

Abstract This article has no abstract. More >

Wei Guo^1,2, Chen Zeng^1,2, Hongye Gou^3,*, Yao Hu^1,2, Hengchao Xu⁴, Longlong Guo^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 491-515, 2019, DOI:10.32604/cmes.2019.06162

Abstract CRTS-II slab ballastless track on bridge is a unique system in China high speed railway. The application of longitudinal continuous track system has obviously changed dynamic characteristics of bridge structure. The bridge system and CRTS-II track system form a complex nonlinear system. To investigate the seismic response of high speed railway (HSR) simply supported bridge-track system, nonlinear models of three-span simply supported bridge with piers of different height and CRTS-II slab ballastless track system are established. By seismic analysis, it is found that shear alveolar in CRTS-II track system is more prone to be damaged… 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 More >

Filipe L. A. Ribeiro^1,*, Andre R. Barbosa², Luis C. Neves³

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 657-676, 2019, DOI:10.32604/cmes.2019.06296

Abstract Although pre-Northridge earthquake steel moment resisting frame buildings have been shown to be susceptible to brittle connection failures, they still represent a large fraction of the existing steel buildings in the United States of America. In this study, the performance of the 3- and 9-story Los Angeles pre-Northridge SAC buildings are analyzed considering ductile and brittle beam-column connection failures, and their uncertainty. This paper contributes to understanding the influence of uncertainty associated with connections brittle fracture on building interstory deformation capacity and its impact on bias and variability of fragility functions and loss assessment. The More >

Haojun Peng^1,*, Zhongwei Wu¹, Jinbing Xia¹, Bolin Dong¹, Yuntao Peng², Linghe Wang³, Xingxing Ma³, Wei Shen³

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 799-813, 2019, DOI:10.32604/cmes.2019.06950

Abstract In this paper, numeric simulations are performed for three dimension models built according to actual surface cleaner in airport runway rubber mark cleaning vehicle using ANSYS FLUENT software on the basis of previous research finished by the authors. After analyzing the simulated flow fields under different standoff distances between nozzle outlet and runway surface and different discharge pressures at nozzle outlet, the relationships of normal stress and shear stress at striking point to outlet pressure and standoff distance are obtained. Finally, the most appropriate discharge pressure at nozzle outlet for the studied surface cleaner model More >

Chenpeng Song^1,2, Yulong Chen^3,*, Jiehao Wang^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 779-797, 2019, DOI:10.32604/cmes.2019.07000

Abstract Hydraulic fracturing has been applied to enhance CBM production and prevent gas dynamical hazard in underground coal mines in China. However, affected by in situ stress orientation, hydrofracture can hardly continuously propagate within coal seam but may easily extend to the adjacent roof-floor strata, causing ineffective permeability enhancement in coal seam and increasing the risk of gas transfinite during mining coal. Thus, it is very necessary to artificially control the propagation direction of hydrofracture and make it well-aligned in large scale in coal seam. In this study, a method for controlling propagation direction of hydrofracture… More >

Ying Zhou^1,*, Peng Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 759-777, 2019, DOI:10.32604/cmes.2019.04383

Abstract This paper proposes a novel three-dimensional (3D) isolation system for facilities and presents the numerical simulation approach for the isolated system under earthquake excitations and impact effect using the OpenSees (Open System for Earthquake Engineering Simulation) software frame work. The 3D isolators combine the quasi-zero stiffness (QZS) system in the vertical direction and lead rubber bearing in the horizontal direction. Considering the large aspect ratio of the isolated facility, linear viscous dampers are designed in the vertical direction to diminish the overturning effect. The vertical QZS isolation system is characterized by a cubic force-displacement relation,… More >