K. Lee¹ and S.W. Lee ²

CMES-Computer Modeling in Engineering & Sciences, Vol.34, No.3, pp. 253-272, 2008, DOI:10.3970/cmes.2008.034.253

Abstract A geometrically nonlinear assumed strain formulation is used to develop a nine-node solid shell element with quadratic displacement through the thickness. The transversely quadratic element allows direct use of the constitutive equations developed for three-dimensional solids, which is convenient when material nonlinearity is involved. The nodal degrees of freedom associated with the quadratic terms in the assumed displacement through the thickness are statically condensed out at the element level. The results of numerical tests conducted on selected example problems demonstrate the validity and effectiveness of the present approach. For the cases involving linear elastic material, More >

Y. C. Shiah¹, C. L. Tan², V.G. Lee³

CMES-Computer Modeling in Engineering & Sciences, Vol.34, No.3, pp. 205-226, 2008, DOI:10.3970/cmes.2008.034.205

Abstract The main impediment to the development of efficient algorithms for the stress analysis of 3D generally anisotropic elastic solids using the boundary element method (BEM) and the local boundary integral equation (LBIE) meshless method over the years is the complexity of the fundamental solutions and the computational burden to evaluate them. The ability to analytically simplify and reduce them into as explicit a form as possible so that they can be directly computed will offer significant cost savings. In addition, they facilitate easy implementation using existing numerical algorithms with the above-mentioned methods that have been More >

C.E. Majorana¹, V.A. Salomoni

CMES-Computer Modeling in Engineering & Sciences, Vol.33, No.1, pp. 49-84, 2008, DOI:10.3970/cmes.2008.033.049

Abstract A dynamic analysis of a thin shell finite element undergoing large displacements and rotations is here presented. The constitutive model adopted derives from the coupling of an hyperelastic basic model fulfilling a De Saint Venant-Kirchhoff criterion with a scalar damage function depending on the maximum value of a suitable strain measure attained through the deformation history; then plastic effects are included using an isotropic/kinematic hardening law. A conservative time integration scheme for the non-linear dynamics of the hyperelastic damaged-plastic thin shell is applied. The main characteristic of the scheme is to be conservative, since it More >

G. M. Kulikov¹, S. V. Plotnikova¹

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.1, pp. 15-38, 2008, DOI:10.3970/cmes.2008.028.015

Abstract This paper presents a robust non-linear geometrically exact four-node solid-shell element based on the first-order seven-parameter equivalent single-layer theory, which permits us to utilize the 3D constitutive equations. The term "geometrically exact" reflects the fact that geometry of the reference surface is described by analytically given functions and displacement vectors are resolved in the reference surface frame. As fundamental shell unknowns six displacements of the outer surfaces and a transverse displacement of the midsurface are chosen. Such choice of displacements gives the possibility to derive strain-displacement relationships, which are invariant under arbitrarily large rigid-body shell More >

E. Ferretti¹, A. Di Leo¹

CMC-Computers, Materials & Continua, Vol.7, No.2, pp. 59-80, 2008, DOI:10.3970/cmc.2008.007.059

Abstract The main assumption on the basis of the identifying model of the effective law, developed by the Author, is the impossibility of considering the specimen as a continuum, when an identifying procedure from load-displacement to stress-strain in uniaxial compression is attempted. Actually, a failure mechanism with propagation of a macro-crack was found to activate from the very beginning of the uniaxial compression test forth. This leads to considering the acquired displacements as composed by two quotes: one constitutive, due to the material strain, and one of crack opening. Since the ratio between these two quotes… More >

Mathew C. Raynor¹, Culley C. Carson², Matthew D. Pearson², Jeffrey W. Nix²

Canadian Journal of Urology, Vol.14, Suppl.6, pp. 63-68, 2007

Abstract A steady decline in androgen levels occurs in males as they age. Evidence suggests that this decline may be at least partially responsible for a variety of physical and mental changes associated with the aging process. For instance, abnormally low levels of androgens can lead to profound changes in bone density, body composition, as well as sexual and cognitive function. Testosterone replacement has been shown to produce improvements in many of these areas. However, this practice is not without risks, both proven and theoretic. Also, the diagnosis of androgen deficiency and the decision to treat More >

K. Hashiguchi¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.4, pp. 257-264, 2007, DOI:10.3970/icces.2007.004.257

Abstract General corotational rate of tensors in arbitrary order having the objectivity is shown first, and then it is verified that the material-derivative of yield condition can be replaced generally to the corotational derivative, i.e. the consistency condition. More >

Shunde Yin¹, Leo Rothenburg¹, Maurice B. Dusseault¹

CMES-Computer Modeling in Engineering & Sciences, Vol.19, No.2, pp. 111-120, 2007, DOI:10.3970/cmes.2007.019.111

Abstract Subsidence problem is of great importance in petroleum engineering and environmental engineering. In this paper, we firstly apply a hybrid Displacement Discontinuity-FEM modeling to this classic problem: the evaluation of subsidence over a compacting oil reservoir. We use displacement discontinuity method to account for the reservoir surrounding area, and finite element methods in the fully coupled simulation of the reservoir itself. This approach greatly reduces the number of degrees of freedom compared to an analyzing fully coupled problem using only a finite element or finite difference discretization. More >

K. Hashiguchi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.17, No.1, pp. 55-62, 2007, DOI:10.3970/cmes.2007.017.055

Abstract Constitutive equation describing the mechanical properties of material has to be formulated in an identical form independent of coordinate systems by which it is described even if there exist any mutual configuration and/or mutual rotation between the material and coordinate systems. This mechanical requirement is attained by describing rate variables as corotational rate tensors with objectivity in constitutive equations in rate form. Besides, in order to use the material-time derivative of yield condition as a consistency condition it has to be replaced to the corotational derivative. In this note a general corotational rate for tensors More >

Ilona Bányász¹, Géza Bokodi¹, Barna Vásárhelyi², András Treszl¹, László Derzbach¹, András Szabó¹, Tivadar Tulassay^1,2,3, Ádám Vannay³

European Cytokine Network, Vol.17, No.4, pp. 271-275, 2006, DOI:10.1684/ecn.2006.0043

Abstract Background. Fabry disease is an X-linked disorder associated with early-onset stroke, cardiomyopathy, and progression to end-stage renal failure. Correlations between inflammatory cytokines have been shown in other lysosomal storage diseases. The aim of the study was to evaluate functional gene polymorphisms of key pro- and anti-inflammatory cytokines and to correlate them to a clinical score to assess the potential role of inflammation in Fabry disease. Design. Genotyping for IL-10[819C/T; -592C/A]; IL-1β[+3954C/T; –511C/T]; IL-1α[-889C/T]; and TNF-α[-308G/A] was performed in 76 patients and correlated with MSSI sub-scores and with enzyme (alpha-galactosidase A) levels. Fifty, normal, age- and… More >