J. M. García-Aznar^1,2, M. A. Pérez^1,2, P. Moreo^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.3, pp. 271-302, 2009, DOI:10.3970/cmes.2009.048.271

Abstract There are many interfaces between biological materials with a structural functionality, where their mechanical behaviour is crucial for their own performance. Advanced tools such as cohesive surface models are being used to simulate the failure and degradation of this kind of biological interactions. The goal of this paper, in a first step, is to present some cohesive surface models that include damage and repair in interfaces and its application to different biomechanical problems. Secondly, we discuss about the main challenges that we have to improve in the modelling of interfaces for a mechanobiological approach. More >

M.Galli , M.L.Oyen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.3, pp. 241-270, 2009, DOI:10.3970/cmes.2009.048.241

Abstract A novel approach is presented for the identification of constitutive parameters of linear poroelastic materials from indentation tests. Load-controlled spherical indentation with a ramp-hold creep profile is considered. The identification approach is based on the normalization of the time-displacement indentation response, in analogy to the well-known one-dimensional consolidation problem. The identification algorithm consists of two nested optimization routines, one in the time-displacement domain and the other in a normalized domain. The procedure is validated by identifying poroelastic parameters from the displacement-time outputs of finite element simulations; the new identification scheme proves both quantitatively reliable and fast. The procedure is also… More >

C. Y. Chen¹, C. Atkinson²

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.3, pp. 219-240, 2009, DOI:10.3970/cmes.2009.048.219

Abstract In this paper, we extend our previous analysis of a contact problem with a circular indenter pressed normally against a semi-infinite elastic composite to that of a semi-infinite viscoelastic composite which consists of a contact layer with uniform thickness welded together with another dissimilar medium. Using the correspondence principle between the Laplace transformed elastic equations and the viscoelastic ones, the asymptotic results derived previously for the pure elastic case are readily adopted for the viscoelastic one with the elastic constants replaced by appropriate functions of Laplace transformed variables for the linear viscoelastic solid. We focus our analysis on the force… More >

J. Sladek¹, V. Sladek¹, P.H. Wen², Y.C. Hon³

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.2, pp. 191-218, 2009, DOI:10.3970/cmes.2009.048.191

Abstract The meshless local Petrov-Galerkin (MLPG) method is used to solve the inverse heat conduction problem of predicting the distribution of the heat transfer coefficient on the boundary of 2-D and axisymmetric bodies. Using this method, nodes are randomly distributed over the numerical solution domain, and surrounding each of these nodes, a circular sub-domain is introduced. By choosing a unit step function as the test function, the local integral equations (LIE) on the boundaries of these sub-domains are derived. To eliminate the time variation in the governing equation, the Laplace transform technique is applied. The local integral equations are nonsingular and… More >

Eugenio Brusa¹, Matteo Nobile²

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.2, pp. 155-190, 2009, DOI:10.3970/cmes.2009.048.155

Abstract Lightness of high pressure vessels is currently assured by composite materials. Construction of over-wrapped composite pressure vessels with inner metallic liner is for instance compatible with standards requirements of the hydrogen technology of energy storage. Therefore a typical layout manufactured by some industries consists of a cylindrical vessel with covering of carbon-epoxy laminates and metallic impermeable liner. To allow the filament winding of the composite fibres are used hoop and helical layers, respectively. A single nozzle is usually built. It requires that the vessel material is reinforced. This need imposes to have a variable thickness in the composite layer. In… More >

Liviu Marin¹

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.2, pp. 121-154, 2009, DOI:10.3970/cmes.2009.048.121

Abstract We investigate the numerical implementation of the alternating iterative algorithm originally proposed by ` 12 ` 12 `$12 `&12 `#12 `^12 `_12 `%12 `~12 *Kozlov91 in the case of the Cauchy problem for the two-dimensional Laplace equation using a meshless method. The two mixed, well-posed and direct problems corresponding to every iteration of the numerical procedure are solved using the method of fundamental solutions (MFS), in conjunction with the Tikhonov regularization method. For each direct problem considered, the optimal value of the regularization parameter is chosen according to the generalized cross-validation (GCV) criterion. An efficient regularizing stopping criterion which ceases… More >

M.V. Menshykova¹, O.V. Menshykov, I.A. Guz

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.2, pp. 107-120, 2009, DOI:10.3970/cmes.2009.048.107

Abstract The study is devoted to the problem for a linear crack located between two dissimilar elastic half-spaces under normally incident time-harmonic plane shear wave. The system of boundary integral equations for displacements and tractions is derived from the dynamic Somigliana identity. The distributions of the displacements and tractions at the bonding interface and the surface of the crack are analysed. The dynamic stress intensity factors (the opening and the transverse shear modes) are computed as functions of the frequency of the incident wave for different material properties. More >

Alfredo Nicolás¹, Blanca Bermúdez², Elsa Báez³

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.1, pp. 83-106, 2009, DOI:10.3970/cmes.2009.048.083

Abstract Numerical results of natural convection flows in two-dimensional cavities, filled with air, are presented to study the effects on the characteristics of the flows as some parameters vary: the Rayleigh number Ra and the aspect ratio A of the cavity. This kind of thermal flows may be modeled by the unsteady Boussinesq approximation in stream function-vorticity variables. The results are obtained with a simple numerical scheme, previously reported for isothermal/mixed convection flows, based mainly on a fixed point iterative process applied to the non-linear elliptic system that results after time discretization. The evolution of the flows, mainly flows converging to… More >

Hua Li¹, Shantanu S. Mulay¹, Simon See²

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.1, pp. 43-82, 2009, DOI:10.3970/cmes.2009.048.043

Abstract Differential Quadrature (DQ) is one of the efficient derivative approximation techniques but it requires a regular domain with all the points distributed only along straight lines. This severely restricts the DQ while solving the irregular domain problems discretized by the random field nodes. This limitation of the DQ method is overcome in a proposed novel strong-form meshless method, called the random differential quadrature (RDQ) method. The RDQ method extends the applicability of the DQ technique over the irregular or regular domains discretized using the random field nodes by approximating a function value with the fixed reproducing kernel particle method (fixed… More >

L.Munteanu¹, V.Chiroiu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.1, pp. 27-42, 2009, DOI:10.3970/cmes.2009.048.027

Abstract The long-range nanoindentation response of carbon nanotubes is studied using a new method that combines the features of Nonlocal Theory and Molecular Mechanics. The deformation of compressed multiple walled carbon nanotubes is investigated, with the emphasis on the simulation of the nanoindentation technique in order to compare the present method to available experimental results. More >