Catálogo de publicaciones - libros

Wide span structures are today widely applied for sport, social, industrial, ecological and other activities. The experience collected in last decades identified structural typologies as space structures, cable structures, membrane structures and new - under tension - efficient materials which combination deals with lightweight structural systems, as the state of art on long span structural design. In order to increase the reliability assessment of wide span structural systems a knowledge based synthetical conceptual design approach is recommended. Theoretical and experimental in scale analysis, combined with a monitoring control of the subsequent performance of the structural system, can calibrate mathematical modelling and evaluate long term sufficiency of design.

This paper is a practical guide to the application of instance-based machine learning techniques to the solution of a financial problem. A broad class of instance-based families is considered for classification using the WEKA software package. The problem selected for analysis is a common one in financial and econometric work: the use of publicly available economic data to forecast future changes in a stock market index. This paper examines various stages in the analysis of this problem including: identification of the problem, considerations in obtaining and preprocessing data, model and parameter selection, and interpretation of results. Finally, the paper offers suggestions of areas of future study for applying instance-based machine learning in the setting of solving financial problems.

In the following an introduction to basic principles of inflated structures, their potential and their limitation is given. Geometry and Shapes are investigated as well as structural differences within high and low pressure structures and their typical pressure control problems. A brief morphological sketch of inflated structures is presented, which opens the room to further development in the future.

Pneumatic structures are usually considered as inalterable, with predetermined features, e.g. shape etc. According to this approach, they cannot be easily rebuilt or modified. Application of techniques current in other sectors of construction industry leads to the structures that are much more flexible and adaptable.

Current work summarizes the experience of the writer in the modeling of membrane systems. A first subsection describes an efficient membrane model, together with a reliable solution procedure. The following section addresses the simulation of the wrinkling phenomena providing details of a new solution procedure. The last one proposes an efficient technique to obtain the solution of the fluid structural interaction problem.

This chapter presents a complete numerical formulation for the nonlinear structural analysis of prestressed membranes with applications in Civil Engineering. These sort of membranes can be considered to undergo large deformations but moderate strains, consequently nonlinear continuum mechanics principles for large deformation of prestressed bodies will be employed in order to proceed with the analysis. The constitutive law adopted for the material will be the one corresponding to a prestressed hyperelastic Saint Venant-Kirchhoff model. To carry out the computational resolution of the structural problem, the Finite Element Method (FEM) will be implemented according to a Total Lagrangian Formulation (TLF), by means of the Direct Core Congruential Formulation (DCCF). Eventually, some numerical examples will be introduced to verify the accuracy and robustness of the aforementioned formulation.

This case study is an investigation of self-generating forms in nature based on pneumatic structures and their use in architectural theory. It focuses on the concept of self organization as a defining principle in nature and in particular, on the mathematical, geometrical and physical properties of bubble clusters and shows examples from nature, biology and engineering. Part of the research resulted in a series of digital models and renderings of different bubble clusters and there polyhedral configuration. Advanced structural design methods are already using systems based upon self-generated models rooted in biological and genetic forms. Engineers are able to input a series of variables into a computer program which in turn, derive a structure using a genetic algorithm resulting in the most efficient use of materials, etc. Numerous examples of such procedures already exist in nature today, in particular, biology. Blueprints for these forms are stored in the genetic code of the DNA of all life forms. Until recent advances in computer technology, the ability to put such genetic algorithms to use has not been possible.

In the last decade complex buildings i.e. with unregular curved surfaces have been designed. The subject of this paper is the construction of those complex buildings. One of the main characteristics of a membrane structure is its geometrical complexity, which can be seen in multiple curved surfaces and complicated connection elements. Modern sophisticated computer technologies can be used to produce easily these complex three-dimensional shapes out of flat strips of fabric. Due to a lack of suitable production methods the expression of the natural stress flow in supporting and connecting (rigid) structural elements is difficult. This paper assumes that it is possible to achieve the architectural desired free forms by manipulation of structural membranes. To prove that it is possible to achieve the architectural desired free forms different cases are described in which this technique is used. The first case describes the design of an indoor Ski run. The second and third case describes the building of a lightweight stage covering and an art pavilion. In all the three cases physical models have been used in the design phase. The structural design of the membrane mould has been engineered with the program easy. The rigidized structures have been analyzed using different FEM programs for each case. The transformation of a form-active structure (membrane) into a surface-active structure has been researched to make domes ore dome-like structures.