Smitha Gopinath^1,2, A. Ramach,ra Murthy¹, Nagesh R. Iyer¹

CMC-Computers, Materials & Continua, Vol.22, No.1, pp. 55-72, 2011, DOI:10.3970/cmc.2011.022.055

Abstract This paper presents the mathematical modeling techniques for nonlinear finite element analysis of RC structure to incorporate uniform corrosion effects. Effect of corrosion has been simulated as reduction in effective cross-sectional area of reinforcing bar, reduction in bonding phenomena and as reduction in material properties of reinforcing bar such as yield strength and elastic modulus. Appropriate constitutive laws for (i) corroded rebar elements and (ii) bond slip with corroded bar have been described. Procedure has been outlined to determine the global damage indicator by secant stiffness based approach. A corroded RC beam has been analysed More >

S.H. Ju¹

CMES-Computer Modeling in Engineering & Sciences, Vol.64, No.1, pp. 91-109, 2010, DOI:10.3970/cmes.2010.064.091

Abstract This study develops an OpenMP scheme to parallel the preconditioned conjugate gradient methods (PCG) in shared memory computers. The proposed method is simple and systematic, so a minor change in traditional PCG methods may produce effective parallelism. At first, the global stiffness matrix is re-numbered in order to produce a parallel three-line form matrix, and a subroutine only needs to be called once in the finite element analysis. Several basic OpenMP commands are then added into the traditional incomplete Cholesky factorization (ILU) and symmetric successive over-relaxation (SSOR) codes to make the procedures of matrix multiplication, More >

K.C. Liao¹, C.L. Chen¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.14, No.4, pp. 103-112, 2010, DOI:10.3970/icces.2010.014.103

Abstract A Taylor-type crystalline plasticity model, implemented into the commercial finite element analysis software, is coded as a subroutine to investigate the behavior of a stainless steel sheet with a body centered cubic (BCC) structure in the current study. Thickness variations of the sheet are examined under the micro-groove formation procedures. Effects of the spatial distribution of crystallographic orientations on the thickness distribution over the sheet are also demonstrated. Numerical results, based on the sheet with textured orientations, are in good agreement with the associated experimental measurements reported in the literature. More >

K.P. Baxevanakis¹, A.E. Giannakopoulos²

CMES-Computer Modeling in Engineering & Sciences, Vol.60, No.2, pp. 181-198, 2010, DOI:10.3970/cmes.2010.060.181

Abstract The present work gives a systematic and rigorous implementation of (edge type) circular Volterra dislocation loops in ordinary axisymmetric finite elements using the thermal analogue and the integral representation of dislocations through stresses. The accuracy of the proposed method is studied in problems where analytical solutions exist. The full fields are given for loop dislocations in isotropic and anisotropic crystals and the Peach-Koehler forces are calculated for loops approaching free surfaces and bimaterial interfaces. The results are expected to be very important in the analysis of plastic yield strength, giving quantitative results regarding the influence More >

F. Auricchio^{1,2,3,4,1,5,1}, M. Contisup>1,5,S. Morgantisup>1,, A. Reali^1,2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.57, No.3, pp. 225-244, 2010, DOI:10.3970/cmes.2010.057.225

Abstract The use of shape memory alloys (SMA) in an increasing number of applications in many fields of engineering, and in particular in biomedical engineering, is leading to a growing interest toward an exhaustive modeling of their macroscopic behavior in order to construct reliable simulation tools for SMA-based devices. In this paper, we review the properties of a robust three-dimensional model able to reproduce both pseudo-elastic and shape-memory effect; then we calibrate the model parameters on experimental data and, finally, we exploit the model to perform the finite element analysis of pseudo-elastic Nitinol stent deployment in More >

L. Dammak, E. Hadj-Taïeb

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.4, pp. 419-430, 2010, DOI:10.3970/fdmp.2010.006.419

Abstract This paper presents a short and focused analysis of the pressure development inside the fluid film related to a journal bearing (i.e. the pressure distribution in the the gap between the shaft, generally referred to as the "journal", and the bearing). The related flow is considered to be isotherm, laminar, steady and incompressible. The lubricant is assumed to be an isoviscous fluid. The Reynolds equation governing the lubricant pressure is derived from the coupled continuity and momentum balance equations written in the framework of the Stokes theory. The non linear system given by coupled equations More >

M. Demiral, A. Roy, V. V. Silberschmidt¹

CMC-Computers, Materials & Continua, Vol.19, No.2, pp. 199-216, 2010, DOI:10.3970/cmc.2010.019.199

Abstract Static indentation experiments are typically performed to characterize the mechanical properties of a material of interest by a rigid indenter of known geometry to various depths. In contrast, dynamic indentation of materials has not been fully studied. Evaluating material performance under dynamic loading conditions is a challenge and we demonstrate that various modelling schemes may be appropriate for different flavours of dynamic indentation. In order to compare underlying thermo-mechanics and deformation processes in a static and dynamic indentation process, indentation of a rigid indenter into a workpiece to a fixed chosen penetration is extensively studied. More >

Taotao Hu¹, gping Shen^1,2

CMC-Computers, Materials & Continua, Vol.17, No.1, pp. 41-58, 2010, DOI:10.3970/cmc.2010.017.041

Abstract In this paper, an axisymmetric indentation model is set up to calculate the effects of the roughness of the thermally grown oxide (TGO) layer, which was modeled as a sinusoidal wave, on the indentation response of the thermal barrier coatings. It is found that the amplitude, wavelength, and thickness of the thermally grown oxide layer have obvious influences on the indentation response, while the effect of the indenter position can be neglected. In the top coating layer, residual stress mainly occurs below the indenter and around the nearest two peaks of the thermally grown oxide More >

Smitha Gopinath¹, J. Rajasankar^1,2, Nagesh R. Iyer¹, T. S. Krishnamoorthy¹, B.H.Bharatkumar¹, N. Lakshmanan¹

Structural Durability & Health Monitoring, Vol.5, No.4, pp. 311-336, 2009, DOI:10.3970/sdhm.2009.005.311

Abstract In this paper, a two-phase strain-based constitutive model is proposed for concrete under tension. First phase deals with modelling uncracked concrete while the behaviour of concrete in cracked condition is modelled in second phase with appropriate theoretical support. A bilinear tension softening curve of concrete defined in crack width-stress space is taken as the basis to propose the model. Smeared representation of reinforcement and cracks along with multi-layered geometry definition of reinforced concrete (RC) structures is used to implement the model. Through this, it is shown that change in the orientation of tensile cracks with… More >

C. K. Chao, J. Lin, C. C. Hsu, Y. Amaritsakul

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.4, pp. 219-221, 2009, DOI:10.3970/icces.2009.009.219

Abstract The gamma nail and dynamic hip screw have been widely used for the treatment of proximal femur fracture. From the clinical point of view, the implants may fail and caused loss of fracture fixation in the impairment of fracture healing. The purposes of this study were to evaluate the performance of those two commercial available fracture fixators and newly design implant (double screw nail).
The whole modeling process was using SolidWork 2006 and then Finite element method was applied to simulate the real situation during the proximal femur treatment. Three types of implants (DHS, TGN, and… More >