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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

In this work a kinematics for laminated beams enriched with a refined formulation ZigZag (RZT), originally presented by Tessler et al. in 2007, introduced in a hierarchical one dimensional type “p” finite element is presented. The finite element employs Lagrange polynomials for the approximation of the degrees of freedom of the ends (nodes) and orthogonal Gram-Schmidt polynomials to the internal degrees of freedoms. This finite element allows a very low discretization, is free of shear locking and behaves very well when the analysis of laminated composites with accurate determination of local stresses and strains at laminar level is necessary. This element has been validated in the analysis of laminated beams with various sequences of symmetric and asymmetric stacking, studying in each case its accuracy and stability. 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 Fil: Oñate, Eugenio. Universidad Politécnica de Catalunya; España 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

This is the peer reviewed version of the following article: [Oller, S. A., Nallim, L. G. and Oller, S. (2016), Fluid dynamic design of an axial rotor for hydrokinetic riverbed turbine-improvement introduced by a high lift foil profile. Environ. Prog. Sustainable Energy, 35: 1198–1206. doi:10.1002/ep.12320], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/ep.12320/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

In the present study, a variational Ritz approach for vibration analysis of thick arbitrarily quadrilateral laminated plates, based on the trigonometric shear deformation theory (TSDT) is developed. In this theory, shear stresses are vanished at the top and bottom surfaces of the laminate and shear correction factors are no longer required. A general straight-sided quadrilateral domain is mapped into a square domain in the computational space using a four-node master plate, employing a geometric transformation. The displacement field components are approximated by sets of beam characteristic orthogonal polynomials generated using the Gram–Schmidt procedure. The use of Ritz method allows a high spectral accuracy and faster convergence rates than local methods such as finite element. The algorithm developed is quite general, free of shear locking and can be used to obtain natural frequencies and modal shapes of laminated plates having various material parameters, geometrical planforms, length-to-thickness ratios and any combinations of free, simply supported and clamped edge support conditions. Through several numerical examples, the capability, efficiency and accuracy of the formulation are demonstrated. Convergence studies and comparison with other existing solutions in the literature suggest that the present algorithm is robust and computationally efficient. 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: 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: 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: Ruano Sandoval, Gonzalo Javier. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Salta. Instituto de Investigaciones para la Industria Quimica. Universidad Nacional de Salta. Facultad de Ingenieria. Instituto de Investigaciones para la Industria Quimica; Argentina

The formulation of an enriched hierarchical one-dimensional finite element suitable to analyze the rheological behavior of thick arbitrarily laminated beams is presented. The formulation is based on the Equivalent Single Layer (ESL) theory and was developed to allow the use of any high-order beam shear deformation theory (HBST) in a unified approach. A generalized Maxwell model was implemented to analyze the time-dependent behavior of the composite. The finite element employs local Lagrange and Hermitian support functions enriched with orthogonal Gram-Schmidt polynomials and is free of shear locking. The enriched macro elements can be used with very coarse meshes and the precision can be controlled without generating a new mesh. The formulation has been validated with numerical examples of symmetric and non-symmetric laminated beams using the three-dimensional finite element program PLCD.

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 chapter presents the composite materials applied to water current turbine (WCT) hydrokinetic turbines. Here will be briefly described the features of these turbines, the fluid-dynamic behavior of the rotor, and its structure formed into a composite material. From the structural viewpoint an advanced composite material formulation that allows an appropriate structural design is introduced. The generalized composite formulations here introduced take into account the nonlinear mechanical behavior of the component materials (matrix and fiber), as the local behavior of plasticity and damage, its anisotropy, the fiber–matrix debonding, its material composition via a general mixing theory, and also the homogenized structural damage index definition.

The formulation of an enriched macro element suitable to analyze the free vibration response of composite plate assemblies is presented in this article. Based on the Trigonometric Shear Deformation Theory (TSDT) and the use of Gram–Schmidt orthogonal polynomials as enrichment functions a finite macro element is developed. In the TSDT framework, shear stresses are vanished at the top and bottom surfaces of the plates and shear correction factors are no longer required. The Principle of Virtual Work is applied to derive the governing equations of motion. A special connectivity matrix is obtained; so that hierarchically enriched global stiffness matrix and mass matrix of general laminated plate structures are derived, allowing to study generally coplanar plate assemblies by combining two or more macro elements. This procedure gives a matrix-eigenvalue problem that can be solved with optimum efficiency. Results of free vibration analysis for symmetric laminated plates of different thickness ratios, geometrical planform shapes and boundary conditions are presented. The accuracy of the formulation is ensured by comparing some numerical examples with those available in the literature.

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

En edificios históricos son conocidos los efectos nocivos de la presencia de humedad en muros, que deteriora detalles de ornamentación, conjuntamente con los componentes de la mampostería que conforma su propia estructura. Es el caso de la Iglesia Nuestra Señora de la Viña (Salta, Argentina), edificio del s. XIX que presentaba manifestaciones patológicas características de las producidas por la presencia de humedad ascendente. Las tareas de recuperación de las superficies exteriores fueron realizadas una vez que el sistema instalado (por electrólisis) deshumidificó los muros. La elevada inversión realizada requiere de un control periódico de la eficacia del sistema. En este trabajo se presentan los fundamentos y los resultados obtenidos con el empleo de georradar como recurso no destructivo para controlar el sistema de deshumidifación, cuya principal ventaja es la de poder detectar en forma precoz a lo largo del tiempo alguna falla en el sistema, evitando en forma indefinida la aparición de nuevas manifestaciones patológicas por humedad ascendente. In historical buildings the harmful effects in masonry due to moisture are well known, as it affects ornamentation and the components of the masonry which is also the building's structure. That is the case of the church Nuestra Señora de la Viña (Salta, Argentina), a XIX cent. building which presented typical pathological symptoms caused by rising damp. An electro physical system was installed in order to dehumidificate the masonry and external surfaces were subsequently recovered. This high investment requires a periodical control of the system's efficiency. This article presents the foundations of and the results obtained by using an impulse radar as a non-destructive resource to control the dehumidification system. Its main advantage is the early detecting of a failure in the system and so avoiding new pathological symptoms caused by rising damp. Fil: Gea, S.. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina 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: 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 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.

The development, computational implementation and application of polynomially-enriched plate macro-element are presented in this work. This macro-element has been formulated by the authors for thin isotropic plates using Gram–Schmidt orthogonal polynomials as enrichment functions and, in this work, the first-order shear deformation theory and the material anisotropy is incorporated. For taking into account plates of several geometrical shapes, an arbitrary quadrilateral laminate is mapped onto a square basic one, so that a unique macro-element can be constructed. The obtained formulation is applied to the static and dynamic analysis of thick composite laminated plates. Besides, it is possible to study generally coplanar plate assemblies by combining two or more macro-elements via a special connectivity matrix. Thus, hierarchically enriched global stiffness matrix, mass matrix, and loading vector of general laminated plate structure are derived. Several different boundary conditions may be arranged in the analysis. This procedure gives a matrix equation of static equilibrium and a matrix-eigenvalue problem that can be solved with optimum efficiency. Numerical obtained results show very good correlation with published results. Besides, the formulation produces stable results and it is computationally efficient. Fil: Rango, Rita Fernanda. 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. International Center for Numerical Methods in Engineering. International Center for Numerical Methods in Engineering; España Fil: Oller, Sergio. International Center for Numerical Methods in Engineering. International Center for Numerical Methods in Engineering; España

Mechanical factors such as stresses and strains play a major role in the growth and remodelling of soft biological tissues. The main constituents of tissue undergo different processes reacting to mechanical stimulus. Thereby, the characterisation of growth and remodelling requires an accurate estimation of the stresses and strains of their main components. Many soft tissues can be considered as composite materials and can be analysed using an appropriate rule of mixtures. Particularly, arterial tissue can be modelled as an isotropic soft matrix reinforced with preferentially oriented collagen fibres. An inverse approach to obtain the mechanical characterisation of each main component is proposed in this work. The procedure is based on a rule of mixtures raised in a finite deformation framework and generalised to include kinematics and compatibility equations for serial–parallel behaviour. This methodology allows obtaining the stress–strain relationship of the components fitting experimental data.

This paper presents a variational formulation for the free vibration analysis of unsymmetrically laminated composite plates with elastically restrained edges. The study includes a micromechanics approach that allows starting the study considering each layer as constituted by long unidirectional fibers in a continuous matrix. The Mori-Tanaka method is used to predict the mechanical properties of each lamina as a function of the elastic properties of the components and of the fiber volume fraction. The resulting mechanical properties for each lamina are included in a general Ritz formulation developed to analyze the free vibration response of thick laminated anisotropic plates resting on elastic supports. Comprehensive numerical examples are computed to validate the present method, and the effects of the different mechanical and geometrical parameters on the dynamical behavior of different laminated plates are shown. New results for general unsymmetrical laminates with elastically restrained edges are also presented. The analytical approximate solution obtained in this paper can also be useful as a basis to deal with optimization problems under, for instance, frequency constraints.

A general algorithm for the free vibration analysis of stepped and tapered beam type structures with multiple elastic supports is developed in this work. The analytical formulation is based on the Ritz method and on the use of orthogonal polynomials within the framework of the first order shear deformation beam theory. To verify the validity and convergence of the general algorithm several numerical examples are analyzed. A further example concerned with the determination of the dynamical properties of a bell tower is also presented and compared with the finite element method and experimental results. Fil: Kohan, Paul Hernán. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación para la Industria Química (i); Argentina Fil: Nallim, Liz. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación para la Industria Química (i); Argentina Fil: Gea, Susana. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Elliptical and circular fibre reinforced composite plates are important structural elements in modern engineering structures. Vibration analysis of these elements are of interest to structural designers. The present paper deals with the free transverse vibration analysis of symmetrically laminated solid and annular elliptic and circular plates with several complicating effects. The approach developed is based on the Rayleigh-Ritz method where the deflection of the plate is approximated by a general shape function of polynomial type. The analysis includes several complicating effects, such as the presence of an internal hole, an internal ring support, several concentrated masses and the boundary elastically restrained against rotation and translation. Several examples are solved and some results which correspond to particular cases are compared with existing values in the literature. New results are also presented for cross-ply and angle-ply elliptical and circular laminates with different boundary conditions. The algorithm developed can be applied to a wide range of elastic restraint conditions, to any aspect ratio and to higher modes. The effect of the restraint parameters along the boundary on the natural frequencies for plates with these complicating effects is considered. © 2008 Elsevier Ltd. All rights reserved. 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: 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

This paper presents a discussion about the results of the article on the vibration of angle-ply symmetric laminated composite rectangular plates with edges elastically restrained, by Ashour (Vibration of angle-ply symmetric laminated composite plates with edges elastically restrained. Compos Struct [in press]). The same problem is treated but with the application of the Ritz method with orthogonal polynomials as coordinate functions. The existence of some inconsistencies in Ashour [in press] is demonstrated. New numerical results for the described plates are included.

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

Triangular fibre reinforced composite plates are important structural elements in modern engineering structures. In this paper a computationally efficient and accurate numerical model is presented for the study of free vibration behaviour of anisotropic triangular plates with edges elastically restrained against rotation and translation. The approach developed is based on the Rayleigh–Ritz method and the use of non-orthogonal right triangular co-ordinates. The deflection of the plate is approximated by a set of beam characteristic orthogonal polynomials generated using the Gram–Schmidt procedure. Several examples are solved and some results which correspond to particular cases are compared with existing values in the literature. New results are also presented for single layer composite plates with different fibre orientations and combinations of boundary conditions. For some plates, mode shapes of free vibration are also shown. Selected new transverse vibration mode shapes are presented to illustrate the effects of boundary constraints, aspect ratio and fibre orientation. The method can be applied to a wide range of elastic restraint conditions, any aspect ratio and for higher modes. The effect of the fibre orientation on the natural frequencies for plates with these restraint conditions are also considered.

The present paper deals with the determination of the boundary and eigenvalue problems that describe the static and dynamic behaviour of anisotropic tapered plates with edges elastically restrained against rotation and translation and nonsmooth boundaries. It is demonstrated that this type of boundary restrictions leads to unstable boundary conditions and that the presence of corner points when the boundary is elastically restrained against translation generates additional boundary conditions. This is particularly interesting in the case of triangular plates.

Real-time electronic speckle pattern interferometry (ESPI) was used for tuning and visualization of natural frequencies of a trapezoidal plate. The plate was excited to resonant vibration by a sinusoidal acoustical source, which provided a continuous range of audio frequencies. Fringe patterns produced during the time-average recording of the vibrating plate—corresponding to several resonant frequencies—were registered. From these interferograms, calculations of vibrational amplitudes by means of zero-order Bessel functions were performed in some particular cases. The system was also studied analytically. The analytical approach developed is based on the Rayleigh–Ritz method and on the use of non-orthogonal right triangular co-ordinates. The deflection of the plate is approximated by a set of beam characteristic orthogonal polynomials generated by using the Gram–Schmidt procedure. A high degree of correlation between computational analysis and experimental results was observed.

Fil: Nallim, Liz. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Salta; Argentina

This paper presents a simple, computationally efficient and highly accurate numerical model for the study of free vibration behaviour of polygonal plates with variable thickness. The approach developed is based on the Rayleigh-Ritz method and the use of non-orthogonal right triangular coordinates. The deflection of the plate is approximated by a set of beam characteristic orthogonal polynomials generated using the Gram-Schmidt procedure. The algorithm is quite general and can be used to study plates with any combinations of clamped, simply supported and free edge support conditions and also different taper and geometric parameters. Several examples are solved and some results are compared with existing values in the literature. New results are also presented for tapered polygonal plates with different geometrical shapes and combinations of boundary conditions. For some polygonal plates, their mode shapes of free vibration are shown. The study of this problem is of practical importance for a better understanding of the vibration of polygonal plates which are commonly encountered in modern technology.

En este capítulo se presenta un procedimiento para evaluar la magnitud del daño local y el daño global en estructuras sometidas a acciones estáticas y dinámicas, con especial énfasis en el problema sísmico. Además de la formulación para la evaluación del daño, se introduce el concepto de refuerzo y reparación estructural mediante laminados compuestos de matriz epóxica con refuerzo de fibras de carbono. Para esta finalidad, se menciona la utilización de la teoría de mezclas para componer un material compuesto a partir de sus componentes básicas. También se evalúa el daño en estas estructuras reforzadas y/o reparadas y se comenta la influencia de estas mejoras en la valoración del daño global de la estructura. Fil: Oller, Sergio Horacio Cristobal. Universidad Politécnica de Catalunya; España. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Molina, Maritzabel. Universidad Nacional de Colombia; Colombia Fil: Vielma, Juan Carlos. Universidad Centroccidental Lisandro Alvarado; Venezuela Fil: Martínez, Xavier. Universidad Politécnica de Catalunya; España Fil: Barbat, Alex H.. Universidad Politécnica de Catalunya; 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

Natural frequencies of tapered orthotropic rectangular plates with a central free hole and edges restrained against rotation and translation are studied by using orthogonal polynomials in the Rayleigh–Ritz method and applying a generalization of the Rayleigh–Schmidt method. The two methods are quite general and can be used to study plates with any combinations of boundary conditions, taper and geometric parameters. To demonstrate the accuracy of the present approach natural frequency coefficients are given for isotropic plates with a central free hole, from which comparison results are available. New results are also given for orthotropic plates with several complicating effects. The studied problems are of interest in several field of engineering, since holes are present in plates due to operational conditions.

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.

This paper presents a simple, accurate and flexible general algorithm for the study of a great number of beams vibration problems. The approach is developed based on the Rayleigh–Ritz method with characteristic orthogonal polynomial shape functions. It allows the inclusion of a number of complicating effects such as varying cross-sections, presence of an arbitrarily placed concentrated mass, ends elastically restrained against rotation and translation and presence of an axial, tensile force. Several cases are treated to show the simplicity and great flexibility of this approach, in the determination of frequencies. To demonstrate the accuracy of the present approach natural frequency coefficients are given for beams, from which comparison results are available. New results are also given for tapered beams with several complicating effects.

The present paper deals with the application of the Rayleigh Schmidt method for the determination of the fundamental frequency coefficient, for rectangular anisotropic plates

It is the purpose of this note to demonstrate that when using this procedure in rectangular plates of non uniform thickness, with edges elastically restrained, the two commonly used expressions that give the stored energy in the elastic supports are not equivalent andthat one of them leads to better results

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

Digital Speckle Interferometry is a non invasive full-field coherent optical technique used in mechanical vibration measurement. In this research, it is used for tuning resonant frequencies of vibrating plates in order to investigate the dynamical behavior of perforated plates. The plate was excited to resonant vibration by a sinusoidal acoustic source. Fringe pattern produced during the time-average recording of the vibrating plate, for several resonant frequencies were registered. Results of plates fixed at one edge having internal holes and attached masses are presented. Experimental natural frequencies and modal shapes are compared to those obtained by an analytical approximate solution based on the Rayleigh–Ritz method with the use of orthogonal polynomials as coordinate function. A high degree of correlation between computational analysis and experimental results was observed, proving the potentiality of the optical technique as experimental validation of the numerical simulations. Fil: Romero, G. G.. Universidad Nacional de Salta. Facultad de Cs.exactas. Departamento de Fisica. Grupo de Optica Laser; Argentina Fil: Alanis, E. E.. Universidad Nacional de Salta. Facultad de Cs.exactas. Departamento de Fisica. Grupo de Optica Laser; Argentina Fil: Martínez, C. C.. Universidad Nacional de Salta. Facultad de Ciencias Naturales; Argentina Fil: Nallim, Liz. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Toledo, M. W.. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina Fil: Alvarez, Liliana del Valle. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina