Leilei Chen¹, Kunpeng Li¹, Xuan Peng², Haojie Lian^3,4,*, Xiao Lin⁵, Zhuojia Fu⁶

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.1, pp. 125-146, 2021, DOI:10.32604/cmes.2021.012821

Abstract This paper presents an isogeometric boundary element method (IGABEM) for transient heat conduction analysis. The Non-Uniform Rational B-spline (NURBS) basis functions, which are used to construct the geometry of the structures, are employed to discretize the physical unknowns in the boundary integral formulations of the governing equations. B´ezier extraction technique is employed to accelerate the evaluation of NURBS basis functions. We adopt a radial integration method to address the additional domain integrals. The numerical examples demonstrate the advantage of IGABEM in dimension reduction and the seamless connection between CAD and numerical analysis. More >

Abdelkarim El Kahoui¹, Mustapha Malek¹, Nouh Izem¹, M. Shadi Mohamed², Mohammed Seaid^3,4,*

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 61-78, 2020, DOI:10.32604/cmes.2020.010874

Abstract We propose a high-order enriched partition of unity finite element method for linear and nonlinear time-dependent diffusion problems. The solution of this class of problems often exhibits non-smooth features such as steep gradients and boundary layers which can be very challenging to recover using the conventional low-order finite element methods. A class of steady-state exponential functions has been widely used for enrichment and its performance to numerically solve these challenges has been demonstrated. However, these enrichment functions have been used only in context of the standard h-version refinement or the so-called q-version refinement. In this paper we demonstrate that the… More >

Jose A. Silva‐Sepulveda¹, Yudy Fonseca², Irine Vodkin³, Gabrielle Vaughn¹, Robert Newbury⁴, Vera Vavinskaya⁵, Jerry Dwek⁶, James C. Perry¹, Preeti Reshamwala⁷, Cynthia Baehling⁸, James Lyon⁹, Christopher Davis¹, Jesse W. Lee¹, Hannah El‐Sabrout¹⁰, Doaa Shahbah¹¹, Laith Alshawabkeh¹², John W Moore¹, Howaida El‐Said¹

Congenital Heart Disease, Vol.14, No.4, pp. 600-608, 2019, DOI:10.1111/chd.12770

Abstract Introduction: Liver fibrosis and cirrhosis are late complications in Fontan palliation. Liver biopsy is the gold standard. The goal of this study is to correlate transjugular liver biopsy (TJLB) in the setting of Fontan palliation with noninvasive testing and hemodynamics.
Methods: Between August 2014 and July 2017, 49 Fontan patients underwent TJLB. All the patients had hemodynamic evaluation, 28 patients had MRE (magnetic reso‐ nance elastography) and 40 patients had cardiopulmonary exercise test. Histologic liver fibrosis was quantitated using traditional histologic scoring systems and a modi‐ fied Ishak congestive hepatic fibrosis score.
Results: Median age 17.8 years, median time since… More >

Lingda Xu¹, Dandi Zhang², Jun Zhou^3,*, Zhou He², Xiao Fang², Yonglin Zhi¹

Energy Engineering, Vol.117, No.1, pp. 19-26, 2020, DOI:10.32604/EE.2020.010409

Abstract For the application of inspecting the construction status of distribution network poles, this paper proposed a novel detection technology for base plates, pulling plates, chucks (abbreviated as BPC) which are buried together with the power poles based on exerting external current excitation. The detection system consists of lead wires for BPC, an excitation generating circuit, a signal receiving coil, a signal conditioning circuit and an embedded processor. Compared with the traditional transient electromagnetic method, this technology is more suitable for detecting BPC which are buried shallowly, with higher sensitivity for depth changes and higher signal-to-noise ratio. Moreover, it can judge… More >

A.V. Ekhlakov², O.M. Khay², Ch. Zhang², J. Sladek³, V. Sladek³

Structural Durability & Health Monitoring, Vol.6, No.3&4, pp. 329-350, 2010, DOI:10.3970/sdhm.2010.006.329

Abstract In this paper, transient crack analysis in two-dimensional, isotropic, continuously non-homo -ge -neous and linear elastic functionally graded materials is presented. A boundary-domain element method based on boundary-domain integral representations is developed. The Laplace-transform technique is utilized to eliminate the dependence on time. Laplace-transformed fundamental solutions of linear coupled thermoelasticity for isotropic, homogeneous and linear elastic solids are applied to derive boundary-domain integral equations. The numerical implementation is performed by using a collocation method for the spatial discretization. The time-dependent numerical solutions are obtained by the Stehfest's inversion algorithm. For an edge crack in a finite domain under thermal shock,… More >

G. Pitarresi¹

Structural Durability & Health Monitoring, Vol.8, No.2, pp. 149-176, 2012, DOI:10.3970/sdhm.2012.008.149

Abstract The present work describes the implementation of active IR Thermography techniques for the NDT of thick polymer and glass-fibre reinforced polymer (GRP) composite panels. A low cost Thermal NDT set-up is proposed, comprising a single-detector IR camera with low thermal resolution and low frame rate, and common low-power halogen lamps as external heat source devices. The use of halogen lamps in particular requires several seconds of switch-on time in order to deliver meaningful and effective heat quantities. The influence of such long heat deposition intervals is investigated on the possibility to implement Transient Thermography and Lock-In Thermography techniques. Regarding the… More >

F. R. M. Romlay¹

Structural Durability & Health Monitoring, Vol.4, No.1, pp. 19-28, 2008, DOI:10.3970/sdhm.2008.004.019

Abstract This paper presents a surface contact static stress of a spur gear system combined with dynamic characteristic using transient Finite Element Method (FEM). Traditionally, the static stress analysis is done separately with dynamic properties due to limitation of complex equation and avoiding of error occurred. However, in this paper, static stress information is combined with the dynamic mechanism due to the time consuming during the design and analysis stage. A transient FEM analysis is carried out to formulate and solve large systems of algebraic equations in order to obtain a relationship between the contact parameter and the kinematics function. The… More >

S. Beyer¹, Ch. Zhang², S. Hirose³, J. Sladek, V. Sladek⁴

Structural Durability & Health Monitoring, Vol.3, No.3, pp. 177-190, 2007, DOI:10.3970/sdhm.2007.003.177

Abstract This paper presents a hypersingular time-domain boundary element method (BEM) for transient dynamic crack analysis in two-dimensional (2-D), homogeneous, anisotropic and linear elastic solids. A finite crack in an infinite or a finite solid subjected to impact loading conditions is investigated. A combination of the classical displacement boundary integral equations (BIEs) on the external boundary and the hypersingular traction BIEs on the crack-faces is applied. The present BEM uses the time-domain dynamic fundamental solutions for anisotropic solids derived by Wang and Achenbach (1994). An explicit time-stepping scheme based on collocation method is developed. Numerical examples for computing the dynamic stress… More >

Yiqiang Li¹, Liang Ma², Zhiqiang Yang³, Xiaofei Guan⁴, Yufeng Nie¹, Zihao Yang^{1, 2}

CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.1, pp. 1-24, 2018, DOI:10.3970/cmes.2018.115.001

Abstract This paper is devoted to the homogenization and statistical multiscale analysis of a transient heat conduction problem in random porous materials with a nonlinear radiation boundary condition. A novel statistical multiscale analysis method based on the two-scale asymptotic expansion is proposed. In the statistical multiscale formulations, a unified linear homogenization procedure is established and the second-order correctors are introduced for modeling the nonlinear radiative heat transfer in random perforations, which are our main contributions. Besides, a numerical algorithm based on the statistical multiscale method is given in details. Numerical results prove the accuracy and efficiency of our method for multiscale… More >

MD. Shamshuddin^{1, *}, C. Balarama Krishna²

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.3, pp. 207-231, 2019, DOI:10.32604/fdmp.2019.00449

Abstract Mathematical model for an unsteady, incompressible, electrically conducting micropolar fluid past a vertical plate through porous medium with constant plate velocity has been investigated in the present study. Heat absorption, Joulian dissipation, and firstorder chemical reaction is also considered. Under the assumption of low Reynolds number, the governing transport equations are rendered into non-dimensional form and the transformed first order differential equations are solved by employing an efficient finite element method. Influence of various flow parameters on linear velocity, microrotation velocity, temperature, and concentration are presented graphically. The effects of heat absorption and chemical reaction rate decelerate the flow is… More >