Ruy Marcelo Pauletti

Ruy Marcelo Pauletti
University of São Paulo | USP · Department of Structural Engineering and Geotechnical (PEF)

Professor, DSc.,Hab.
Professor at University of São Paulo, Brazil

About

120
Publications
51,802
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369
Citations
Introduction
born in 1961, received in 1992 his DSc. in Structural engineering from the University of São Paulo, where he is currently Full Professor, researching in the fields of tension structures and non-linear structural analysis..
Additional affiliations
January 1988 - present
University of São Paulo
Position
  • Professor (Associate)

Publications

Publications (120)
Article
Full-text available
Pneumatic structures are the tensile structures par excellence, since only with them it is possible to have all elements working in tension. This paper describes the evolution of pneumatic structures, as well as several issues related to its design, such as different pattering methods, the distinctions between high and low energy systems, and wheth...
Chapter
Full-text available
The article presents a general framework for the nonlinear equilibrium analysis of taut structures, such as cables and membranes. Distinction is done between geometric and constitutive stiffness, and all the relevant matrices for truss and membrane finite element static analyses are derived, including the effects of sliding cables and following for...
Article
Full-text available
This work presents, with the aid of the natural approach, an extension of the force density method for the initial shape finding of cable and membrane structures, which leads to the solution of a system of linear equations. This method, here called the natural force density method, preserves the linearity which characterizes the original force dens...
Article
Pressurized thin-wall structures cover a broad range of applications, including storage tanks, pressurized rubber flood barriers, and large span enclosures. To accurately model such structures, the analyst must select the appropriate mechanical formulation (e.g.membrane vs shell). Membranes are assumed to have negligible bending stiffness and respo...
Article
Besides material and geometric stiffness, usual components affecting tension structures in general, pneumatic structures are endowed with a pneumatic stiffness, which corresponds to a reluctance of the pressure envelope to change its volume. The higher the inside pressure, the more relevant this component can be. Researches on the nonlinear behavio...
Article
Full-text available
The new paradigms of parametric modelling have been proving promising on the advance of systems for analysis and design of taut (or tensile) structures. With this premise, the presented work consist on the development with a form-finding tool for Computer Aided Design(CAE) and Computer Aided Engineering (CAE) integration using VPL (Visual Programmi...
Article
This paper presents an adjoint-based method for solving optimization problems involving pressurized membrane structures subject to external pressure loads. Shape optimization of pressurized membranes is complicated by the fact that, lacking bending stiffness, their three-dimensional shape must be sustained by the internal pressure of the inflation...
Conference Paper
Full-text available
This paper proposes the discussion on design and construction of thin shells structures based on experimental models produced with flexible surface moulds. Recent researches have proposed alternative flexible formworks, composed by textiles membranes or films, stressed by different techniques. Among the alternative production techniques explored he...
Article
Lightweight structures in grid form made of elements joined together with nodes are called reticulated shells, or gridshells. We propose a new connection system and method for gridshell structures. The connection system applies to grids that have a high variability of curvature and connection parameters. The connection uses standardized hub geometr...
Conference Paper
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This paper presents the steps of design, fabrication and installation of a Styrofoam masonry vault, produced in 2018 at the Polytechnic School at the University of São Paulo (POLI-USP), in the context of a graduate course on Light Structures. The challenge of the project was to design and deliver an innovative structural prototype, in a relevant sc...
Conference Paper
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This paper describes a 'learning by doing' experience conducted during an undergraduate course on Structural Systems at the Faculty of Architecture at the University of São Paulo. The experience was inspired on the educational project 'Design, Assemble and Dismantle (DAD Project)' devised by S.A. Behnejad at the Department of Civil and Environmenta...
Article
The Natural Force Density Method (NFDM) is a convenient method for finding configurations of mem- branes and funicular shell structures, providing viable equilibrium geometries in a single linear equilib- rium analysis. It is an extension of the Force Density Method (FDM), first proposed by Linkwitz in 1971, as convenient alternative for finding co...
Thesis
Full-text available
My old thesis at the University of Padua, Italy.
Article
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This study presents a new form finding method for tensegrity membrane structures. The form finding problem is formulated as an unconstrained nonlinear programming problem, where the total potential energy of a structure composed of strut and membrane elements is minimized. The strut element can function as a truss element or as an element that show...
Conference Paper
Full-text available
Resumo Apresenta-se um estudo completo dos efeitos do vento sobre uma torre de telecomunicações. Trata-se de uma estrutura em balanço, engatada na base, composta de segmentos tubulares de seção circular em concreto pré-moldado. Flanges de aço parafusadas conectam os segmentos. Além de considerações de resistência, o controle de deslocamentos e vibr...
Conference Paper
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his work considers the use of a type of "sliding cable" element that includes the effect of friction to represent the behavior of tendons in prestressed structures. The sliding cable element can potentially model the prestressing tendons in connection to a broader class of structural elements. In order to test its performance in prestressing applic...
Conference Paper
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Neste trabalho discutem-se alguns aspectos relativos à modelagem numérica da protensão sem aderência, por meio do método dos elementos finitos. Inicialmente faz-se uma revisão crítica dos modelos encontrados na literatura, apontando deficiências e melhorias necessárias. Neste sentido, apresenta-se uma proposta para modelagem que consiste na utiliza...
Conference Paper
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O principal objetivo deste trabalho foi avaliar as propriedades mecânicas dos tecidos estruturais por meio de ensaios de tração uniaxiais e biaxiais. Para isso, foi desenvolvido um arranjo de ensaio que permitiu a aplicação das forças de tração. As deformações foram medidas por meio de extensômetros elétricos e com isso, foi possível traçar o diagr...
Conference Paper
Full-text available
This paper presents the preliminary results of a research on pneumatic structures under development at the Faculty of Architecture and Urban Planning and the Polytechnic School of the University of São Paulo. It describes the evolution of pneumatic structures-the tension structures par excellence-, relating their historical context with their struc...
Conference Paper
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This paper presents the initial activities of an ongoing research on the analysis of orthotropic membranes, considering geometrical nonlinearity. The subject is relevant for t he consistent description of the materials used in the production of the current structural membranes and for the proper consideration of wrinkling in such type of structures...
Conference Paper
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This work presents the numerical and physical models developed during the design of the membrane roof of the amphitheater of the "Memorial dos Povos de Belém do Pará" (MPBP), as well as the fabrication and construction of the actual membrane. The MPBP is a new public space, recently opened by the City of Belém (main city of the State of Pará, Brazi...
Conference Paper
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This paper investigates the application of artificial neural networks to structural engineering. Artificial neural networks are based on intelligent organism neural networks, which learn by experience, and constitute a powerful computational tool, used in different areas of science. The purpose of present application is to explore alternative metho...
Conference Paper
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This workoutlines a research on tensegrity structures, currently (2005) under development at the Department of Stuctural and Foundation Engineering of the Polytechnic school of the Univeristy of São Paulo.
Conference Paper
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This work outlines a research on tensegrity structures, currently under development at the Department of Structural and Foundation Engineering of the Polytechnic School of the University of São Paulo. A methodology is proposed to simulate de erection of tensegrity cable-domes, which can conveniently represented by a set of nonlinear, geometrically...
Conference Paper
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O processo de aprendizado pode ser muito mais completo quando se alia a teoria à prática. Este trabalho apresenta a experiência da disciplina de pós-graduação 'Sistemas Estruturais Leves para Cobertura de Grandes Vãos', em que se emprega esta premissa como base de um modelo educacional motivador. O curso está dividido em aulas expositivas, aulas pr...
Conference Paper
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This paper presents the development of a useful membrane element based on Argyris' natural formulation, making distinction between the constitutive and geometric parts of the element tangent stiffness. The mathematical development considers large displacements but linear elastic material behavior, yielding a very simple element, yet able to cope wi...
Conference Paper
Full-text available
The force density concept provides a very practical procedure for finding viable shapes for taut structures, such as cable and membrane structures. This work presents the force density procedure within the formalism of structural matrix analysis, yielding an algorithm which can be easily implemented into a linear structural analysis program, and wh...
Conference Paper
Full-text available
Pneumatics are tensile structures par excellence, since only with them it is possible to have all elements working exclusively in tension. This paper discusses the main aspects of the design methodology, which is applied to the design and construction of a double-skin pneumatic toy, and the production of a small pneumatic dome. Results from the num...
Conference Paper
Full-text available
This paper presents a brief review on the theoretical developments on minimal surfaces, highlighting the important analogy between the problems of finding minimal area surfaces and of finding membrane surfaces with homogeneous and isotropic stress fields. A purely geometric methodology for the determination of this class of surfaces is presented, b...
Conference Paper
Full-text available
This work presents the mathematical formulation and the application of the dynamic relaxation method to the problems of shape finding and patterning of cable and membrane structures, as well as the search of geodesic lines onto membrane surfaces. The methodology is verified through an application to an existent structure built in Brazil. Comparison...
Conference Paper
Full-text available
This paper explores the form finding analysis of tensioned fabric cone structures with bi-planar symmetry using the natural force density method. Of particular interest is the circumferential distribution of the resulting stress field generated with this method. The results offer great promise in analyzing cone structures of more general shape.
Conference Paper
Full-text available
O procedimento das densidades de força é uma alternativa conveniente para a busca da forma de estruturas retesadas, como as redes de cabos e as membranas. Embora as idéias subjacentes sejam surpreendentemente simples, muitas das exposições encontradas na literatura são pouco sistemáticas. O presente trabalho procura responder a esta limitação, apre...
Conference Paper
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Tensegrity é, segundo Richard Buckminster Füller, o princípio estrutural pelo qual a forma da estrutura é garantida pela interação entre uma rede contínua de cabos tracionados e um conjunto de elementos comprimidos, isolados entre si. As estruturas tensegrity fazem parte de um grupo de estruturas que somente são possíveis de existir a partir da apl...
Conference Paper
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This paper presents the case of a large membrane built in Brazil in 2004, which collapsed in 2005 and was rebuilt in 2007. Located in Paulínia, a city located 120km from São Paulo, it was composed of an asymmetrical conical tent, 42m high, and covered an area of about 2220m 2. The paper describes the analyses developed to infer the possible causes...
Conference Paper
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Um dos problemas encontrados na análise estática não-linear de estruturas, por meio do método de Newton, é que a matriz de rigidez tangente da estrutura pode se tornar indeterminada, com a conseqüente divergência do método. Isto é particularmente grave no caso das estruturas de cabos e membranas, que podem se comportar como mecanismos. Um método al...
Conference Paper
Full-text available
This paper discusses the Natural Force Density Method, an extension of the well known Force Density Method for the shape finding of continuous membrane structures, which preserves the linearity of the original method, overcoming the need for regular meshes. Abstract The Force Density Method (FDM), first proposed by Linkwitz and Scheck (1974) is a c...
Conference Paper
Full-text available
We propose a finite-difference scheme to assemble Newton's Method Jacobian matrices, whose columns are seen as directional derivatives of the system's residual vector, with respect to each of its degrees of freedom. The generality, simplicity and easy implementation of the proposed method encourage its use, whenever exact Jacobian matrices are not...
Conference Paper
Full-text available
This paper discusses the Natural Force Density Method, an extension of the well known Force Density Method for the shape finding of continuous membrane structures, which preserves the linearity of the original method, overcoming the need for regular meshes. The method is capable of providing viable membrane configurations, comprising the membrane s...
Conference Paper
Full-text available
This paper presents numerical and experimental studies on the structural behaviour of glued-laminated wood beams, investigating the parameters that characterize their lateral stability, and providing a useful criterion to assess the unbraced length limits for various types of large span structures. The identification and quantification of the pheno...
Conference Paper
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The problem of the equilibrium shape of a membrane structure between two coaxial rings of equal radii separated by a specified distance with a fixed ratio between the meridianal and circumferential stress is explored. The maximum separation between the rings for a given stress ratio is determined, as well as the associated reduction in radius at th...
Conference Paper
Full-text available
The problem of the equilibrium shape of a membrane structure between two coaxial rings of identical elliptical shape separated by a specified distance with a fixed ratio between the meridianal and circumferential stress is explored. The maximum separation between the rings for a given stress ratio is determined, as well as the associated reduction...
Conference Paper
Full-text available
This paper presents the implementation of a simple wrinkling/slackening model into the classical Argyris membrane element, comparing the solution performance by Newton's iterations, using either the tangent stiffness matrix (numerically evaluated through a finite-difference approximation), or a secant stiffness matrix (obtained through the modifica...
Conference Paper
Full-text available
This paper presents the implementation of a simple wrinkling/slackening model into the classical Argyris membrane element, comparing the solution performance by Newton's iterations, using either the tangent stiffness matrix (numerically evaluated through a finite-difference approximation), or a secant stiffness matrix (obtained through the modifica...
Conference Paper
Full-text available
This paper outlines the evolution of tensile structures in Latin America, briefly reporting some successful cases produced during the last two decades in countries of the region. A summary on the series of Latin American Symposia on Tensile Structures and on the creation of the Latin American Network for Tensile Structures is also presented.
Article
Full-text available
O número de casos noticia-dos de outras estruturas de concreto armado, além das barragens, afetadas pela Reação Álcali-Agregado (RAA) é crescente. A deterio-ração induzida pela RAA impacta dire-tamente os requisitos mínimos exigidos pelas normas, relativos aos aspectos funcionais e operacionais, a perda de capacidade resistente e a durabilidade e s...
Conference Paper
Full-text available
The problem of the equilibrium shape of a membrane structure between two coaxial rings of identical elliptical shape separated by a specified distance with a fixed ratio between the meridianal and circumferential stress is explored. The maximum separation between the rings for a given stress ratio is determined, as well as the associated reduction...
Conference Paper
Full-text available
This work describes the design and the construction of a membrane-tensegrity sculpture, developed in the context of a graduate course on light structures at the University of São Paulo. The structure combines compressive struts and a continuous membrane, to shape an octahedral star, whose equilibrium conditions are much alike a tensegrity module. A...
Conference Paper
Full-text available
Umbrellas are paradigmatic cases of bending-active structures, where the initially straight ribs are bent by the action of the membrane canopy but, reciprocally, the canopy is prestressed by the bending of the ribs. Since the geometry of these elements depends on their mutual interaction, a viable configuration of an umbrella, comprising its geomet...
Conference Paper
Full-text available
It is common wisdom that a lot can be learned from the critical review of failures, but detailed reports on membrane collapses are seldom available to a broader audience. This paper presents the case of a large asymmetrical conical membrane built in Brazil in 2004. The structure was 42m tall, inscribed in a 56m by 55m rectangle, and covering an are...
Conference Paper
Full-text available
This paper presents the details and key aspects of the application of structural topology optimization to the shape finding of an ultra-high performance concrete (UHPC) staircase. The choice of the mesh size, boundary conditions, material properties, and restrictions are some of the aspects discussed in this study. The optimized geometry is used as...
Preprint
Full-text available
Umbrellas are paradigmatic cases of bending-active structures, where the initially straight ribs are bent by the action of the membrane canopy but, reciprocally, the canopy is prestressed by the bending of the ribs. Since the geometry of these elements depends on their mutual interaction, a viable configuration of an umbrella, comprising its geomet...
Preprint
Full-text available
In designing cable net structures for civil engineering applications (e.g. roofs, façades), engineers aim to minimize deformations under static loading. However, some cable net structures can undergo large deformations and are subjected to mainly dynamic loads. This work explores the design of a moored cable net shark barrier in La Réunion, which m...
Preprint
Full-text available
In designing cable net structures for civil engineering applications (e.g. roofs, façades), engineers aim to minimize deformations under static loading. However, some cable net structures can undergo large deformations and are subjected to mainly dynamic loads. This work explores the design of a moored cable net shark barrier in La Réunion, which m...
Conference Paper
Full-text available
This paper presents the design, analysis, and fabrication of a membrane sculpture based on the Costa minimal surface. The work was developed during the Spring of 2016 at Princeton University as a pedagogical exercise combining the mathematics of minimal shapes with the major aspects of membrane structure design. Three different numerical form findi...
Conference Paper
Full-text available
This paper investigates the potential application of digital tools into the design and fabrication of textile weave through the combined use of form finding and the traditional technique of bobbin lace. The work explores how a traditional handcrafted method could lead to a new approach surrounding parametric and generative design in conjunction wit...
Conference Paper
Full-text available
This paper presents a comparison of three different form finding methods available in ixCube 4.10, a specialized software for the design and analysis of membrane structures. A variety of membrane models with different geometry are evaluated, considering the computer time, resulting geometry, and tension distribution, as provided by the Force Densit...
Conference Paper
Full-text available
A summary of the work done for over a decade on the shaping of conoid membrane structures with unequal biaxial stresses is presented in an order that reflects, in hindsight, the body of knowledge accumulated on the subject. Critical results from the previous work are presented with a new point of view that reflects this evolution of understanding o...
Conference Paper
Full-text available
The Force Density Method (FDM), first proposed by Linkwitz and Scheck in 1974 is a convenient alternative for finding configurations of cable nets and membranes, since it provides viable geometries in a single linear equilibrium analysis. The Natural Force Density Method (NFDM) is an extension of the FDM to the shape finding of membrane structures,...
Conference Paper
Full-text available
In this paper, we present the development of a NFDM plugin for Rhino/Grasshopper environment, that allows quick and robust parametric generation of bending-free shapes, either reticulated or continuous, which we subsequently optimize using other Grasshopper plugins (Karamba and Galapagos). Even though convergence of genetic algorithm is usually slo...
Article
Full-text available
In the last two decades, a renewed interest has arisen, both from the structural engineering and architectural field, to exploit the elegance and structural efficiency of structural surfaces. This paper discusses a project-based course aimed at graduate architecture and civil engineering students to i) develop an in-depth understanding of the basic...