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This article presents the formulation of an enriched macro finite element based on the trigonometric shear deformation theory for the static analysis of symmetrically laminated composite plates. Shear correction factor is not required because this theory accounts for tangential stress-free boundary conditions on the plate boundary surfaces. The macro element is obtained using the principle of virtual work and Gram-Schmidt orthogonal polynomials as enrichment functions. The implementation of the obtained algorithm is simple and efficient, and allows studying general quadrilateral plates with a single macro element. Several examples are presented to show the capability and applicability of the developed formulation. Fil: Rango, Rita Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Oller Martinez, Sergio Horacio. Universidad Politécnica de Catalunya; España

This paper presents a general constitutive model for tissue stress driven growth and necrotic remodeling. The general theoretical framework is given by a kinematics formulation in large strain. The model allows the analysis of tissue behaviour considering the coupling of biological and mechanical fields, through the implementation of an internal variable that represents the bioavailability, together with the growth induced by mechanical stimuli. To take into account the tissue necrosis phenomenon a reinterpretation of the classical theory of mixtures is proposed. The proposed formulation is based on the consideration of two components, normal tissue and necrotic tissue, each one with its own volumetric participation, which is treated in an evolutive way, allowing simulating the phenomena of ischemia. This article also presents a brief description of the numerical implementation of the model as well as the obtained results, which shows the process of necrosis of part of the tissue, its influence on the surrounding healthy tissue, and the interaction between the nutrients availability and the stress driven growth and necrotic remodeling process. © 2012 Elsevier Ltd. All rights reserved. Fil: Bellomo, Facundo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Armero, F.. University of California at Berkeley; Estados Unidos Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Politécnica de Catalunya; España Fil: Oller, S.. Universidad Politécnica de Catalunya; España

The effect of traffic vibrations on buildings is of special interest as its sources have multiplied becoming a concern for residents or for those who work, visit or preserve buildings of heritage value. The problem has their origin in characteristics such as the deterioration of the roads or concentration of public transport routes in adjacent streets. The effect of these vibrations has been the object of study in recent years, with works referred to especially experimental determinations, whose results can be used to assess whether the measurements obtained are within accepted values by some regulations. These results can also be used to calibrate global numerical models to determine this influence analyzing attenuation measures. This paper proposes a global model of finite elements that allows dealing with the treatment of traffic-induced vibrations in structures and analyzing an alternative of solution according to the location. The model includes the building under study, land and surrounding constructions to have orientative results of the whole including its boundary conditions. The actions caused by the traffic are established through impulses that define the load states to be applied. Finally, an alternative is proposed to analyze the options to mitigate the effect of the generated vibrations. Fil: Quinteros, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Barbat, Alex. Universidad Politecnica de Catalunya. Escuela de Ingenieria de Barcelona Este.; España Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Oller, Sergio Horacio Cristobal. Universidad Politecnica de Catalunya. Escuela de Ingenieria de Barcelona Este.; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina

This work shows possibilities and limitations of the refined zigzag theory (RZT) that has been used in different structural (beam, plate and shell) finite elements. The refined zigzag theory can deal with composite laminates, adding only one nodal degree of freedom per spatial dimension of the laminate, obtaining very good accuracy. It assumes that the in-plane displacements have a piece-wise linear shape across the thickness depending on the shear stiffness of each composite layer. This paper presents the main aspects of a beam/shell of revolution element used for the numerical simulations. The details of the refined zigzag theory are given also in order to discuss some limitations that occur when dealing with the non-linear phenomenon of delamination. Two examples are presented and discussed, including different inhomogeneities that show the limitations of the RZT for the treatment of partially delaminated beams. Fil: Flores, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados en Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Estudios Avanzados en Ingeniería y Tecnología; Argentina Fil: Oller, Sergio Horacio Cristobal. International Center for Numerical Method Engineering; España. Technical University of Catalonia; España Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina

This work presents a general formulation and implementation in solid-shell elements of the refined zigzag theory and the trigonometric shear deformation theory in an unified way. The model thus conceived is aimed for use in the analysis, design and verification of structures made of composite materials, in which shear strains have a significant prevalence. The refined zigzag theory can deal with composite laminates economically, adding only two nodal degrees of freedom, with very good accuracy. It assumes that the in-plane displacements have a piece-wise linear shape across the thickness depending on the shear stiffness of each composite layer. The trigonometric theory assumes a cosine variation of the transverse shear strain. A modification of this theory is presented in this paper allowing its implementation with C0 approximation functions. Two existing elements are considered, an eight-node tri-linear hexahedron and a six-node triangular prism. Both elements use a modified right Cauchy-Green deformation tensor C¯ where five of its six components are linearly interpolated from values computed at the top and bottom surfaces of the element. The sixth component is computed at the element center and it is enhanced with an additional degree of freedom. This basic kinematic is improved with a hierarchical field of in-plane displacements expressed in convective coordinates. The objective of this approach is to have a simple and efficient finite element formulation to analyze composite laminates under large displacements and rotations but small elastic strains. The assumed natural strain technique is used to prevent transverse shear locking. An analytic through-the-thickness integration and one point integration on the shell plane is used requiring hourglass stabilization for the hexahedral element. Several examples are considered on the one hand to compare with analytical static solutions of plates, and on the other hand to observe natural frequencies, buckling loads and the non-linear large displacement behavior in double curved shells. The results obtained are in a very good agreement with the targets used. Fil: Flores, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Estructuras; Argentina Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Oller, Sergio Horacio Cristobal. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Politécnica de Catalunya; España. Centre Internacional de Mètodes Numèrics En Enginyerie; Argentina

This paper is concerned with the bending of laminated composite plates with arbitrary lay-up and general boundary conditions. The analysis is based on the small deflection, first-order shear deformation theory of composite plates, which utilizes the Reissner-Mindlin plate theory. In solving the aforementioned plate problems, a general algorithm based on the Ritz method and the use of beam orthogonal polynomials as coordinate functions is derived. This general algorithm provides an analytical approximate solution that can be applied to the static analysis of moderately thick laminated composite plates with any lamination scheme and combination of edge conditions. The convergence, accuracy, and flexibility of the obtained general algorithm are shown by computing several numerical examples and comparing some of them with results given in the literature. Some results, including general laminates and nonsymmetrical boundary conditions with free edges, are also presented.

This work presents a numerical analysis of the ability of the high lift airfoil profile Selig S1223 for working as hydrofoil under water conditions. The geometry of the hydrofoil blade is designed through a suitable airfoil profile and then studied carefully by means of Computational Fluid Dynamics (CFD) in order to check its hydrodynamic behavior, i.e., including lift and drag analysis, and determinations of streamlines velocities and pressures fields. Finally conclusions on the use of this profile in a possible application for hydrokinetic turbine blades are detailed. Fil: Oller Aramayo, Sergio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; Argentina Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; Argentina Fil: Oller, S.. Universidad Politecnica de Catalunya; España

This paper shows an integrated structural design optimization of a composite rotor-hydrofoil of a water current turbine by means the finite elements method (FEM), using a Serial/Parallel mixing theory (Rastellini et al. Comput. Struct. 86:879–896, 2008, Martinez et al., 2007, Martinez and Oller Arch. Comput. Methods. 16(4):357–397, 2009, Martinez et al. Compos. Part B Eng. 42(2011):134–144, 2010) coupled with a fluid-dynamic formulation and multi-objective optimization algorithm (Gen and Cheng 1997, Lee et al. Compos. Struct. 99:181–192, 2013, Lee et al. Compos. Struct. 94(3):1087–1096, 2012). The composite hydrofoil of the turbine rotor has been design using a reinforced laminate composites, taking into account the optimization of the carbon fiber orientation to obtain the maximum strength and lower rotational-inertia. Also, these results have been compared with a steel hydrofoil remarking the different performance on both structures. The mechanical and geometrical parameters involved in the design of this fiber-reinforced composite material are the fiber orientation, number of layers, stacking sequence and laminate thickness. Water pressure in the rotor of the turbine is obtained from a coupled fluid-dynamic simulation (CFD), whose detail can be found in the reference Oller et al. (2012). The main purpose of this paper is to achieve a very low inertia rotor minimizing the start-stop effect, because it is applied in axial water flow turbine currently in design by the authors, in which is important to take the maximum advantage of the kinetic energy. The FEM simulation codes are engineered by CIMNE (International Center for Numerical Method in Engineering, Barcelona, Spain), COMPack for the solids problem application, KRATOS for fluid dynamic application and RMOP for the structural optimization. To validate the procedure here presented, many turbine rotors made of composite materials are analyzed and three of them are compared with the steel one.

A general variational formulation for the determination of natural frequencies and mode shapes of free vibration of laminated trapezoidal and triangular plates is presented in this work. The kinematics corresponding to the first order shear deformation plate theory (FSDT) is used to take into account the effects of shear deformation and rotary inertia in the analysis. This theory allows obtaining greater accuracy of frequency coefficients corresponding to higher modes vibration, even for the thin plates. The developed approach is based on the Ritz method and the plate geometry is approximated by nonorthogonal right triangular co-ordinates. The transverse deflection and two rotations of the laminate are independently approximated by sets of simple polynomials automatically generated. The algorithm allows obtaining approximate analytical solutions for laminated plates with different shapes, aspect ratio, number of layers, stacking sequence, angle of fiber orientation and boundary conditions including translational and rotational elastically restrained edges. The algorithm is simple to program and numerically stable. Additionally, triangular plates can be generated as a special case. Fil: Quintana, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación Para la Industria Química (i); Argentina Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación Para la Industria Química (i); Argentina. Universidad Catolica de Salta. Facultad de Ingenieria E Informatica; Argentina

Some of the key factors that regulate growth and remodeling of tissues are fundamentally mechanical. However, it is important to take into account the role of bioavailability together with the stresses and strains in the processes of normal or pathological growth. In this sense, the model presented in this work is oriented to describe the growth of soft biological tissue under "stress driven growth" and depending on the biological availability of the organism. The general theoretical framework is given by a kinematic formulation in large strain combined with the thermodynamic basis of open systems. The formulation uses a multiplicative decomposition of deformation gradient, splitting it in a growth part and viscoelastic part. The strains due to growth are incompatible and are controlled by an unbalanced stresses related to a homeostatic state. Growth implies a volume change with an increase of mass maintaining constant the density. One of the most interesting features of the proposed model is the generation of new tissue taking into account the contribution of mass to the system controlled through biological availability. Because soft biological tissues in general have a hierarchical structure with several components (usually a soft matrix reinforced with collagen fibers), the developed growth model is suitable for the characterization of the growth of each component. This allows considering a different behavior for each of them in the context of a generalized theory of mixtures. Finally, we illustrate the response of the model in case of growth and atrophy with an application example.

This paper presents investigations of free vibration of anisotropic plates of different geometrical shapes and generally restrained boundaries. The existence and uniqueness of weak solutions of boundary value problems and eigenvalue problems which correspond to the statical and dynamical behaviour of the mentioned plates is demonstrated. It is determined that when the plates have corner points formed by the intersection of edges free or elastically restrained against translation, the corresponding bilinear forms maintain the V - ellipticity property. Also, an analytical formulation, based on the Ritz method and polynomial expressions as approximate functions for analysing the free vibrations of laminated plates with smooth and non-smooth boundary with non-classical edge supports is presented. Numerical results are presented for circular, elliptical and trapezoidal plates for different boundary conditions and material properties. © 2007 Elsevier Inc. All rights reserved. Fil: Grossi, Ricardo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina

The calibration of a general model for composite materials and its application to the case of fiber reinforced composite laminates are presented in this paper. The constitutive equation for the composite results from the combination of the constitutive equations of the laminae that, in turn, are obtained from the combination of fibers and matrix. The behavior of each component is simulated by a general elastoplastic anisotropic model. The combination rules obey to the microstructure of the composite. In order to calibrate the general model, the behavior of composites formed by laminae reinforced with unidirectional fibers is studied. Three-dimensional finite element models are used to study the distribution of stresses and strains inside the composite. These finite element models are useful to verify the hypotheses of the proposed composites theory, in a relatively simple way. Comparisons between elastic properties of laminae obtained with the finite elements model, with Mori-Tanaka method, with the model for composite studied and experimental results are included in the paper. Elastic properties of laminates with different stacking sequences and fibers orientations are also obtained. Additionally, application examples showing the non-linear response of laminae and laminates obtained with the calibrated model and comparisons with experimental results are presented. The results show that the calibrated model describes the behavior up to failure of composite laminates. The failure mode of the composite produced by the failure of one or more of its components can be identified. The calibrated model is also able to reproduce complex failure modes that change from the matrix to the fibers depending on the type of stress state. © 2008 Elsevier Ltd. All rights reserved. Fil: Toledo, Mario Walter Efraín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina Fil: Luccioni, Bibiana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán; Argentina

A general analytical-numerical approach developed for the dynamical analysis of unsymmetrically laminated plates of general quadrilateral planforms is presented in this work. An arbitrary quadrilateral thin flat laminate is mapped onto a square basic one, so that a unique macro-element is constructed for the whole plate. The Ritz method is applied to evaluate the governing equation in which the coupling effects of bending and stretching are contained. All possible transverse boundary conditions combining with the different in-plane constraints are considered in the analysis. The resulting algorithm possesses great flexibility, it is easy to program and it needs minimal input information. For these reasons, the proposed methodology results convenient for large scale structural design and analysis where repeated calculations are often required. © 2007 Elsevier Ltd. All rights reserved. Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina Fil: Oller, Sergio Horacio Cristobal. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Politécnica de Catalunya; España

Based on the classical laminated plate theory, a variational approach for the study of the statical and dynamical behaviour of arbitrary quadrilateral anisotropic plates with various boundary conditions is developed. The analytical formulation uses the Ritz method in conjunction with natural coordinates to express the geometry of general plates in a simple form. The deflection of the plate is approximated by a set of beam characteristic orthogonal polynomials generated using the Gram-Schmidt procedure. The algorithm developed is quite general and can be used to study fibre reinforced composite laminates with symmetric lay-ups, which may have general anisotropy and any combinations of clamped, simply supported and free edge support conditions. Various numerical applications are presented and some results are compared with existing values in the literature to demonstrate the accuracy and flexibility of the present method. New results were also determined for plates with different geometrical shapes, combinations of boundary conditions, several stacking sequences and various angles of fibre orientation. Fil: Nallim, Liz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Oller, Sergio Horacio Cristobal. Universidad Politécnica de Catalunya; España. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Grossi, Ricardo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina