Yunfa Zhang¹, Xiaozhou Xia^{1, *}, Zhenjie Wu¹, Qing Zhang¹

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 413-442, 2020, DOI:10.32604/cmc.2020.04660

Abstract Considering the fact that the initial defects, like the imperfect interfacial transition zones (ITZ) and the micro voids in mortar matrix, weaken the mechanical properties of concrete, this study develops corresponding constitutive models for ITZ and matrix, and simulates the concrete failure with finite element methods. Specifically, an elastic-damage traction-separation model for ITZ is constructed, and an anisotropic plastic-damage model distinguishing the strength-difference under tension and compression for mortar matrix is proposed as well. In this anisotropic plastic-damage model, the weakening effect of micro voids is reflected by introducing initial isotropic damage, the distinct characteristic of tension and compression which… More >

Takeo Matsumoto^1,*, Chizuru Hirooka¹, Yong Fan¹, Junfeng Wang¹, Naoki Mori¹, Eijiro Maeda¹

Molecular & Cellular Biomechanics, Vol.16, Suppl.2, pp. 81-81, 2019, DOI:10.32604/mcb.2019.07102

Abstract Aortic wall thickens in response to hypertension. Many studies reported that the wall thickening occurs to maintain the wall stress in the circumferential direction at a constant level. In case of the longitudinal direction, however, there are few studies suggesting the constancy of the stress. Such anisotropic response may be attributable to the circumferential alignment of the smooth muscle cells (SMCs) in the wall [1]. However, to the authors’ knowledge, there are no study discussing the underlying mechanism of the anisotropic response. It has been reported that mechanical deformation of the nuclei causes transcription upregulation [2]. This might suggest that… More >

J. Useche, P. Sollero, E.L. Albuquerque¹, L. Palermo²

Structural Durability & Health Monitoring, Vol.4, No.2, pp. 107-116, 2008, DOI:10.3970/sdhm.2008.004.107

Abstract The fracture analysis of cracked thick plates repaired with adhesively bonded composite patches using a boundary element formulation is presented. The shear deformable cracked isotropic plate was modeled using the dual boundary method. In order to model the repair, a three parameter boundary element formulation was established. This formulation is based on Kirchhoff's theory for symmetric layer composite plates and considers the transversal deflection and two in-plane rotations. Interaction forces and moments between the cracked plate and the composite repair were modeled as distributed loading, and discretized using continuous and semi-discontinuous domain cells. Coupling equations, based on kinematic compatibility and… 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 >

P.D. Shah¹, Ch. Song², C.L. Tan¹, X. Wang¹

Structural Durability & Health Monitoring, Vol.2, No.4, pp. 225-238, 2006, DOI:10.3970/sdhm.2006.002.225

Abstract Numerical T-stress solutions in two dimensional anisotropic cracked bodies are very scarce in the literature. Schemes to evaluate this fracture parameter in anisotropy have been reported only fairly recently. Among them are those developed in conjunction with two different computational techniques, namely, the Boundary Element Method (BEM) and the Scaled Boundary Finite-Element Method (SBFEM). This paper provides a review of the respective schemes using these techniques and demonstrates their efficacy with three examples. These examples, which are of engineering importance, involve cracks lying in a homogeneous medium as well as at the interface between dissimilar media. The numerical T-stress solutions… More >

J. Sladek¹, V. Sladek, Ch.Zhang²

Structural Durability & Health Monitoring, Vol.1, No.2, pp. 131-144, 2005, DOI:10.3970/sdhm.2005.001.131

Abstract A meshless method based on the local Petrov-Galerkin approach is proposed for crack analysis in two-dimensional (2-d), anisotropic and linear elastic solids with continuously varying material properties. Both quasi-static and transient elastodynamic problems are considered. For time-dependent problems, the Laplace-transform technique is utilized. A unit step function is used as the test function in the local weak-form. It is leading to local boundary integral equations (LBIEs) involving only a domain-integral in the case of transient dynamic problems. The analyzed domain is divided into small subdomains with a circular shape. The moving least-squares (MLS) method is adopted for approximating the physical… More >

Y.C. Shiah¹, Y.M. Lee², Chi-Chang Wang²

CMC-Computers, Materials & Continua, Vol.33, No.3, pp. 229-255, 2013, DOI:10.3970/cmc.2013.033.229

Abstract In this paper, the boundary integrals for treating 3D field problems are fully regularized for planar elements by the technique of integration by parts (IBP). As has been well documented in open literatures, these integrals appear to be strongly singular and hyper-singular for the associated fundamental solutions. In the past, the IBP approach has only been applied to regularize the integrals for 2D problems. The present work shows that the IBP can also be further extended to treat 3D problems, where two variables of the local coordinates are involved. The presented formulations are fully explicit and also, most importantly, very… More >

Z. Neffah¹, H. Kahalerras^{1, *}, B. Fersadou¹

FDMP-Fluid Dynamics & Materials Processing, Vol.14, No.1, pp. 39-56, 2018, DOI:10.3970/fdmp.2018.014.039

Abstract A numerical study of heat and mass transfer in a non-Newtonian fluid in a parallel-plate channel partly filled with an anisotropic porous medium and subjected to an exothermic chemical reaction on its walls has been conducted. The flow field in the porous region has been modeled by the modified Brinkman-Forchheimer extended Darcy model for power-law fluids and a finite volume method has been used to solve the governing equations. The influence played by a variation of the anisotropic ratio on thermal conductivity, power-law index, Darcy number, and chemical reaction characteristics has been examined. We show that the anisotropy of a… More >

P. Vena¹, R. Contro

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 497-506, 2003, DOI:10.3970/cmes.2003.004.497

Abstract The adoption of artificial ligaments in current surgery is still characterised by a low success rate due to the fact that mechanical properties of the biomedical devices are such that a biomechanical compatibility is not fully satisfied. A durable artificial ligament should exhibit stiffness as well as strength properties which are such that a full articulation functionality is guaranteed. To this purpose, reliable numerical methods able to predict the mechanical behaviour of such devices both in the elastic and in inelastic range until complete rupture, could be used for designing of devices with tailored mechanical properties.

The present… More >

Yao-Ming Zhang, Zhao-Yan Liu, Jeng-Tzong Chen

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.3, pp. 71-72, 2011, DOI:10.3970/icces.2011.018.071

Abstract Abstract The presentation is mainly devoted to the research on the regularized boundary integral equations with indirect unknowns for anisotropic elastic problems. Based on a new idea, a novel regularization technique is pursued, in which the nonsingular indirect BIE excluding the CPV and HFP integrals is established. The proposed indirect BEM has many advantages. Firstly, the anisotropic problems to be considered can be solved directly without transforming them into isotropic ones so that no inverse transform is required. Secondly, the proposed method doesn't need to calculate multiple integral as the Galerkin method, and but rather treat CPV integrals indirectly, so… More >