Chengquan Wang¹, Yonggang Shen^2,*, Yun Zou¹, Tianqi Li¹, Xiaoping Feng¹

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.1, pp. 75-93, 2018, DOI:10.3970/cmes.2018.114.075

Abstract The failure behavior of the precast prestressed concrete T girder was investigated by destructive test and finite-element analysis, and the mid-span deflection, girder stiffness and the variation of the cross section strain in the loading process were obtained, and the mechanical properties, mechanical behavior, elastic and plastic behavior and ultimate bearing capacity of T girder with large span were revealed. Furthermore, the relationship between the beam stiffness degradation, the neutral axis in cross-section, steel yielding and concrete cracking are investigated and analyzed. A method was proposed to predict the residual bearing capacity of a bridge More >

Qiang Tong¹, Qingwen Ren^{1, *}, Lei Shen ², Linfei Zhang ², Yin Yang³

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.1, pp. 33-58, 2018, DOI:10.3970/cmes.2018.114.033

Abstract In this article, the post-peak softening stage of the constitutive relation and the elastic stiffness degradation of concrete are investigated, and a highly reasonable constitutive relation curve is proposed. At the material level, the energy change in the concrete failure process is studied based on the different stress-strain curves of concrete under uniaxial tension and compression. The concrete failure criterion based on elastic strain energy density is deemed suitable and consistent with the experimental phenomena. The hysteresis phenomenon (lags behind the peak strength) is also discussed. At the structure level, the strength reduction method is More >

Xiaozhong Chen^1,*, Zhijian Mao¹

Molecular & Cellular Biomechanics, Vol.15, No.4, pp. 229-241, 2018, DOI:10.32604/mcb.2018.03818

Abstract Shape optimization of orthopedic fixation plate is of great importance in the treatment of complex fracture. Therefore, a method in this paper to automatically optimize the complex shape of anatomical plate according to static analysis. Based on the theory of finite element analysis (FEA), our approach is processed as follows. First, the three-dimensional finite element model of the fracture fixation is constructed. Next, according to the type and feature of fracture, the anatomical plate was parameterized in two levels (the bounding surface and plate model). Then, parameter constraints are set up to meet the needs More >

Qingyu Wang¹, Dalin Tang^1,2,*, Gador Canton³, Zheyang Wu², Thomas S. Hatsukami⁴, Kristen L. Billiar⁵, Chun Yuan⁶

Molecular & Cellular Biomechanics, Vol.15, No.4, pp. 189-201, 2018, DOI:10.32604/mcb.2018.04572

Abstract Cardiovascular diseases are closely linked to atherosclerotic plaque development and rupture. Assessment of plaque vulnerability is of fundamental significance to cardiovascular research and disease diagnosis, prevention, treatment and management. Magnetic resonance image (MRI) data of carotid atherosclerotic plaques from 8 patients (5 male, 3 female; age: 62-83, mean=71) were acquired at the University of Washington (UW), Seattle by the Vascular Imaging Laboratory (VIL) with written informed consent obtained. Patient-specific vessel material properties were quantified using Cine MRI data for modeling use. 3D thin-layer models were used to obtain plaque stress and strain for plaque assessment.… More >

Molecular & Cellular Biomechanics, Vol.15, No.1, pp. 51-61, 2018, DOI:10.3970/mcb.2018.015.051

Abstract Tracheal stenosis is a common respiratory disease and is usually treated by stent implantation. However, the implanted stent often causes excessive hyperplasia of trachea granulation tissue, leading to the restenosis. Although surgical removal or chemical suppression can be used to alleviate the restenosis, the efficacy is limited. Thus, restenosis remains a thorny complication. We investigated this issue from the perspective of the “tress-growth”relationship. Firstly, the lower airway of 5 experimental dogs were CT-scanned to reconstruct the 3D numerical models; secondly, the implantations of the Nitinol alloy stents were numerically simulated; thirdly, 45 days after the… More >

Duraisamy Velmurugan¹, Masilamany Santha Alphin^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.2, pp. 125-141, 2018, DOI:10.31614/cmes.2018.01817

Abstract This study aims to investigate the effects of variable thread pitch on stress distribution in bones of different bone qualities under two different loading conditions (Vertical, and Horizontal) for a Zirconia dental implant. For this purpose, a three dimensional finite element model of the mandibular premolar section and three single threaded implants of 0.8 mm, 1.6 mm, 2.4 mm pitch was designed. Finite element analysis software was used to develop the model and three different bone qualities (Type II, Type III, and Type IV) were prepared. A vertical load of 200 N, and a horizontal… More >

Z. Xu¹, M. Chen¹, X. M. Fan^1,2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.3, pp. 407-431, 2018, DOI:10.31614/cmes.2018.01816

Abstract The alternating method based on the fundamental solutions of the infinite domain containing a crack, namely Muskhelishvili’s solutions, divides the complex structure with a crack into a simple model without crack which can be solved by traditional numerical methods and an infinite domain with a crack which can be solved by Muskhelishvili’s solutions. However, this alternating method cannot be directly applied to the edge crack problems since partial crack surface of Muskhelishvili’s solutions is located outside the computational domain. In this paper, an improved alternating method, the spline fictitious boundary element alternating method (SFBEAM), based More >

Sihan Chen¹, Bao Li¹, Haisheng Yang¹, Jianhang Du², Xiaoling Li², Youjun Liu^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.2, pp. 149-162, 2018, DOI:10.31614/cmes.2018.04133

Abstract Enhanced external counterpulsation (EECP) is able to treat myocardial ischemia, which is usually caused by coronary artery stenosis. However, the underlying mechanisms regarding why this technique is effective in treating myocardial ischemia remains unclear and there is no patient-specific counterpulsation mode for different rates of coronary artery stenosis in clinic. This study sought to investigate the hemodynamic effect of varied coronary artery stenosis rates when using EECP and the necessity of adopting targeted counterpulsation mode to consider different rates of coronary artery stenosis. Three 3-dimensional (3D) coronary models with different stenosis rates, including 55% (Model… More >

Yanxia Wang¹, Yu Wang², Siqi Li³, ur Rehman Aziz³, Shutian Liu¹, Kairong Qin^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.2, pp. 127-147, 2018, DOI:10.31614/cmes.2018.03985

Abstract Assessment of the magnitude and pattern of wall shear stress (WSS) in vivo is the prerequisite for studying the quantitative relationship between exercise-induced WSS and arterial endothelial function. In the previous studies, the calculation of the WSS modulated by exercise training was primarily based upon the rigid tube model, which did not take non-linear effects of vessel elastic deformation into consideration. In this study, with an elastic tube model, we estimated the effect of a bout of 30-minute acute cycling exercise on the WSS and the flow rate in the common carotid artery according to… More >

A. Khechiba¹, Y. Benakcha¹, A. Ghezal¹, P. Spetiri²

FDMP-Fluid Dynamics & Materials Processing, Vol.14, No.2, pp. 137-154, 2018, DOI:10.3970/fdmp.2018.04054

Abstract This work investigates the dynamic behavior of a pulsatile flow electrically conducting through porous medium in a cylindrical conduit under the influence of a magnetic field. The imposed magnetic field is assumed to be uniform and constant. An exact solution of the equations governing magneto hydro-dynamics (MHD) flow in a conduit has been obtained in the form of Bessel functions. The analytical study has been used to establish an expression between the Hartmann number, Darcy number and the stress coefficient. The numerical method is based on an implicit finite difference time marching scheme using the More >