Conservación de la simetría en el mallado topológico de estructudas tensadas

La generación de los patrones de corte resulta un paso imprescindible a la hora de realizar el diseño de una estructura tensada. Si la estructura para la cual hay que realizar los patrones es, en principio, simétrica, el diseñador tratará de mantener esta simetría en el mallado de la estructura para lograr un patronaje más simple y barato que el que se obtendría como resultado de un mallado asimétrico. Así, en el caso de una estructura cuyo soporte externo presenta simetría, la forma de la estructura tensada ideal sería también simétrica. Al usar el mallado topológico (MT) junto al método de la densidad de fuerza (MDF) para encontrar una primera forma de equilibrio de una estructura tensada con un soporte externo simétrico, se observa que la simetría en el mallado no siempre se conserva. Este problema se encuentra relacionado con el procedimiento de mallado que se introduce en a búsqueda de la forma de equilibrio. Sin embargo, el empleo de una serie de reglas simples a la hora de construir la topología para la malla permite conservar la simetría en la misma. Este artículo proporcionará un algoritmo que incluye esa serie de reglas y que será probado con varios ejemplos para ilustrar la aplicabilidad de esas prescripciones.Trabajo de investigación tutelada, Universidad de Granada. Departamento de Mecánica de Estructuras e Ingeniería Hidraúlica. Curso académico 2010/2011

Detailed application of the Linear Acceleration Method for the response of an elasto-plastic SDOF system

The numeric computation procedure for the solution of the equation of motion of a single-degree-of-freedom (SDOF) system subjected to any type of ground acceleration is exhaustively presented. The followed numeric approach is the Linear Acceleration Method, i.e. Newmark’s Method with and . The approach allows considering any time of multilinear elasto-plastic behavior. It also allows computing the Complete Hysteretic Curve of the SDOF system

Report TEP 190 1-2019

Report TEP 190 1-2019The numeric computation procedure for the solution of the equation of motion of a single-degree-of-freedom (SDOF) system subjected to any type of ground acceleration is exhaustively presented. The followed numeric approach is the Linear Acceleration Method, i.e. Newmark’s Method with γ=1/2 and β=1/6. The approach allows considering any time of multilinear elasto-plastic behavior. It also allows computing the Complete Hysteretic Curve of the SDOF system

Bars overlapping in tensegrity structurs belonging to the Octahedron family.

When performing the form-finding process of full-forms of tensegrity structures it is observed that beyond the double-expanded octahedron, struts overlapping occurs in space, making practicably impossible to materialize the tensegrity to employ it as a real structure. As the spatial coordinates of nodes that determine the geometry of the structure are provided as a linear combination of vectors composing a base of null space of the tensegrity force density matrix, an analytical study is carried out to check the existence of any combination of those vectors that avoids the overlapping of bars.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Strength design optimization of structural steel members according to Eurocode3

In order to design a steel member subjected to a bending moment and an axial load, there are an infinite number of possible solutions of I- or H‐steel cross-sections, the doubly-symmetric solution being just one of them. This paper presents a procedure to obtain the optimal steel cross-section from the infinite number of possible solutions. The process is based on the Reinforcement Sizing Diagrams employed in reinforced concrete strength design. The procedure looks for any type of solution regarding compact or non-compact steel sections. All aspects related to local instabilities are taken into account, as well as some special considerations in order to address the global instabilities associated with the slenderness of the steel element.The present work was financed by the Spanish Ministry of Education. The first author is a Spanish Government PhD fellow (FPU grant AP 2010‐3707)

Optimization of structural steel members with non-compact sections according to EC3

Para el diseño de un elemento estructural tipo viga-columna se suelen seleccionar secciones doblemente simétricas, generalemente secciones laminadas tipo H o I. Sin embargo, ésta es sólo una de las muchas soluciones posibles y, por lo general, no será la sección óptima. Hernández-Montes et al. 2004, y Hernández-Montes et al. 2005, proponen los diagramas RSD (Reinforcement Sizing Diagrams) como un método para obtener la solución óptima para el armado longitudinal de una sección de hormigón sometida a flexión uniaxial y a compresión. Esta metodología ha sido extendida para secciones de acero compactas según el Eurocódigo 3 (EC3) por Gil-Martín et al. 2008, y esta comunicación procederá de manera similar para buscar soluciones no compactas, esto es, soluciones en clases 3 ó 4 según EC3, considerando todos los aspectos relacionados con la aparición de inestabilidades locales. Además, se introducirán las consideraciones especiales para tener en cuenta las inestabilidades globales relacionadas con la esbeltez del miembro.In a designed structure, the chosen section for a member as a steel beam-column will be doubly-symmetric and it will correspond to one provided by a standard rolled steel section as H or I. However, this solution is just one of the big number of possible solutions and the optimal one may correspond to other section different from the symmetric one. Hernandez-Montes et al. 2004, and Hernández-Montes et al. 2005, proposed the Reinforcement Sizing Diagrams (RSD) as an approach for getting the optimal solution for the longitudinal reinforcing steel of a concrete section subjected to uniaxial bending and compression This methodology is extended for compact steel sections according to Eurocode 3 (EC3) by Gil-Martín et al. 2008 and this communication will proceed similarly for seeking non compact solutions, this is, sections corresponding to Class 3 or 4 according to EC3, considering all the aspects related with the appearance of local instabilities. Furthermore, special considerations are introduced to address the global instabilities associated with the slenderness of the steel element.TEP-19

Octahedron family: the double-expanded octahedron tensegrity

Es un preprintThe octahedron family of tensegrity structures is presented in this research. The octahedron and the expanded octahedron (well-known tensegrities in the literature) are the first and second components of the family. A new tensegrity is presented: the double-expanded octahedron. This new tensegrity form was obtained following the connectivity pattern of the octahedron family presented in this work. The values of the force densities or force:length ratios that satisfy the minimum required rank deficiency of the force density matrix were computed analytically. Two types of solutions are obtained: full and folded forms. Results show that each lower member of the octahedron family is a folded form of a superior member of this family. Several examples are shown.Grupo de Investigación TEP-19

Symmetry preserving in Topological Mapping for tension structures

When using Topological Mapping (TM) together with the Force Density Method (FDM) in order to find a first form of equilibrium for a tension structure whose fixed nodes coincide in plan view with the vertices of a regular polygon, it has been observed that the symmetry may be lost. The problem is related to the mapping procedure that is introduced in the process. However, if some rules are followed in constructing the topology for the mesh, the symmetry can be preserved. With a symmetric mesh, the later cutting pattern generation process becomes simpler, easier, and cheaper. This paper will provide one simple algorithm that has been proved to work effectively in preserving the symmetry in the cited type of tension structures. Several examples are presented in order to better illustrate the applicability of these easy prescriptions.Grupo TEP 190This research work was carried out under the financial support provided by Spanish Ministry of Education and Science as part of the Research Projects BIA 2007-62595. The first author is a Spanish Government PhD fellow (FPU Grant AP 2010-3707)

II Jornadas de la Sociedad Española para la Conservación y Estudio de Los Mamíferos (SECEM) Soria 7-9 diciembre 1995

Seguimiento de una reintroducción de corzo (Capreolus capreolus) en ambiente mediterráneo. Dispersión y área de campeoModelos de distribución de los insectívoros ern la Península IbéricaDieta anual del zorro, Vulpes vulpes, en dos hábitats del Parque Nacional de DoñanaDesarrollo juvenil del cráneo en las poblaciones ibéricas de gato montés, Felis silvestris Schreber, 1777Presencia y expansión del visón americano (Mustela vison) en las provincias de Teruel y Castellón (Este de España).Preferencias de hábitat invernal de la musaraña común (Crocidura russula) en un encinar fragmentado de la submeseta norteUso de cámaras automáticas para la recogida de información faunística.Dieta del lobo en dos zonas de Asturias (España) que difieren en carga ganadera.Consumo de frutos y dispersión de semillas de serbal (Sorbus aucuparia L.) por zorros y martas en la cordillera Cantábrica occidentalEvaluación de espermatozoides obtenidos postmorten en el ciervo.Frecuencia de aparición de diferentes restos de conejo en excrementos de lince y zorroAtlas preliminar de los mamíferos de Soria (España)Censo y distribución de la marmota alpina (Marmota marmota) en Navarra.Trampeo fotográfico del género Martes en el Parque Nacional de Aigüestortes i Estany de Sant Maurici (Lleida)Peer reviewe

Sistemas de retención de tierras para la reducción de la energía de contrucción

Tesis Univ. Granada. Departamento de Mecánica de estructuras e Ingeniería Hidráulic