Sfoglia per Autore "Aravas, N."
Items 21-40 di 45
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Material modeling of biofilm mechanical properties
Laspidou, C. S.; Spyrou, L. A.; Aravas, N.; Rittmann, B. E. (2014)A biofilm material model and a procedure for numerical integration are developed in this article. They enable calculation of a composite Young's modulus that varies in the biofilm and evolves with deformation. The ... -
Mechanics models for hydrogen embrittlement mechanisms
Liang, Y.; Sofronis, P.; Dodds Jr, R. H.; Aravas, N. (2005)Of the many suggestions of hydrogen-induced degradation of engineering materials, two mechanisms appear to be viable in non-hydride forming systems: hydrogen-enhanced localized plasticity (HELP) and hydrogeninduced decohesion. ... -
Mixed finite element formulations of strain-gradient elasticity problems
Amanatidou, E.; Aravas, N. (2002)Theories on intrinsic or material length scales find applications in the modeling of size-dependent phenomena. In elasticity, length scales enter the constitutive equations through the elastic strain energy function, which, ... -
Modelling of transformations in TRIP steels
Katsamas, A. I.; Haidemenopoulos, G. N.; Aravas, N. (2004)Industrial processing of low-alloy Transformation Induced Plasticity (TRIP) steels involves various stages of heat-treating, such as Intercritical Annealing (IA) and Bainitic Isothermal Treatment (BIT), in order to produce ... -
Multiscaling effects in low alloy TRIP steels
Haidemenopoulos, G. N.; Katsamas, A. I.; Aravas, N. (2007)Low-alloy TRIP steels are a new class of steels with excellent combinations of strength and formability, which offer a unique field for the study of multiscale effects in materials, in the sense that experimental observations ... -
Multiscaling effects in TRIP steels
Haidemenopoulos, G. N.; Aravas, N. (2006) -
Muscle and Tendon Tissues: Constitutive Modeling and Computational Issues
Spyrou, L. A.; Aravas, N. (2011)A three-dimensional constitutive model for muscle and tendon tissues is developed. Muscle and tendon are considered as composite materials that consist of fibers and the connective tissues and biofluids surrounding the ... -
Muscle-driven finite element simulation of human foot movements
Spyrou, L. A.; Aravas, N. (2012)This paper describes a finite element scheme for realistic muscle-driven simulation of human foot movements. The scheme is used to simulate human ankle plantar flexion. A three-dimensional anatomically detailed finite ... -
A numeric-symbolic approach to the problem of localization of plastic flow
Boussaa, D.; Aravas, N. (2001)A method combining numerical and symbolic computations is presented for deciding whether or not a mechanical state given numerically in terms of its fourth-order tenser of moduli satisfies the localization condition, and ... -
Numerical methods for porous metals with deformation-induced anisotropy
Aravas, N.; Castaneda, P. P. (2004)A constitutive model for porous metals subjected to general three-dimensional finite deformations is presented. The model takes into account the evolution of porosity and the development of anisotropy due to changes in the ... -
Numerical modeling of elasto-plastic porous materials with void shape effects at finite deformations
Danas, K.; Aravas, N. (2012)A new constitutive model for elasto-plastic (rate-independent) porous materials subjected to general three-dimensional finite deformations is presented. The new model results from simple modifications of an earlier model ... -
On the calculation of the elastic modulus of a biofilm streamer
Aravas, N.; Laspidou, C. S. (2008)Biofilm mechanical properties are essential in quantifying the rate of microbial detachment, a key process in determining the function and structure of biofilm systems. Although properties such as biofilm elastic moduli, ... -
On the effect of hydrogen on plastic instabilities in metals
Liang, Y.; Sofronis, P.; Aravas, N. (2003)Experimental observations and theoretical calculations have demonstrated that hydrogen solute atoms increase the dislocation mobility in metals and alloys, thus promoting highly localized plastic processes which eventually ... -
Plane asymptotic crack-tip solutions in gradient elasticity
Aravas, N.; Giannakopoulos, A. E. (2009)An asymptotic crack-tip solution under conditions of plane strain is developed for a material that obeys a special form of linear isotropic strain gradient elasticity. In particular, an elastic constitutive equation of the ... -
Plane-Strain Problems for a Class of Gradient Elasticity Models-A Stress Function Approach
Aravas, N. (2011)The plane strain problem is analyzed in detail for a class of isotropic, compressible, linearly elastic materials with a strain energy density function that depends on both the strain tensor epsilon and its spatial gradient ... -
Porous metals with developing anisotropy: Constitutive models, computational issues and applications to deformation processing
Kailasam, M.; Aravas, N.; Castaneda, P. P. (2000)A constitutive model for a porous metal subjected to general three-dimensional finite deformations is presented. The model takes into account the evolution of porosity and the development of anisotropy due to changes in ... -
Prediction of collapse of the osteonecrosis of the hip by determining location and size of the lesion: A 2 to 17 years study
Koumpoyiannis, S. D.; Aravas, N.; Houstis, E. N.; Moraitis, T.; Varitimidis, S.; Malizos, K. (2010)Osteonecrosis of the femoral head is a disease responsible for a large number of arthroplasties in young and active patients in the western world. Prediction of outcome of the disease remains a difficult task. The purpose ... -
Prognosis of collapse of the osteonecrosis of the femoral head for patients treated with a tantalum rod by determining location and size of the lesion
Koumpoyiannis, S. D.; Aravas, N.; Varitimidis, S.; Malizos, K.; Houstis, E. N. (2009)The purpose of this study is to predict the osteonecrosis of the femoral head by examining the location and size of the lesion of the femoral head. A triangulation approximation algorithm is used for the computation of the ... -
Recent advances in the study of hydrogen embrittlement at the University of Illinois
Sofronis, P.; Robertson, M.; Liang, Y.; Teter, D. F.; Aravas, N. (2003)This paper summarizes recent work at the University of Illinois on the fundamental mechanisms of hydrogen embrittlement. Our approach combines experimental and theoretical methods. We describe the theoretical work on hydride ... -
A reciprocity theorem in linear gradient elasticity and the corresponding Saint-Venant principle
Giannakopoulos, A. E.; Amanatidou, E.; Aravas, N. (2006)In many practical applications of nanotechnology and in microelectromechanical devices, typical structural components are in the form of beams, plates, shells and membranes. When the scale of such components is very small, ...