Formulaçao de um elemento finito de cabo incorporando o efeito do atrito (Elemento de cabos escorregando)

O trabalho apresenta a formulacáo geometricamente exata e a implementaçao computacional de um elemento finito de cabo que permite o escorregamento em presenca de atrito. O novo elemento fornece procedimentos naturais para simular o processo de montagem e a resposta aos carregamentos de estruturas de cabos em geral, além de ter campos promissores de aplicaçáo no modelamento de estruturas de concreto protendido e no estudo de oscilaçoes auto-excitáveis. Resultados de exemplos elementares sáo discutidos.Peer Reviewe

Formulaçao de um elemento finito de cabo incorporando o efeito do atrito (Elemento de cabos escorregando)

O trabalho apresenta a formulacáo geometricamente exata e a implementaçao computacional de um elemento finito de cabo que permite o escorregamento em presenca de atrito. O novo elemento fornece procedimentos naturais para simular o processo de montagem e a resposta aos carregamentos de estruturas de cabos em geral, além de ter campos promissores de aplicaçáo no modelamento de estruturas de concreto protendido e no estudo de oscilaçoes auto-excitáveis. Resultados de exemplos elementares sáo discutidos.Peer Reviewe

Direct area minimization through dynamic relaxation

Minimal surfaces, characterized by the property of a minimal area within a fixed boundary, offer an interesting design option for membrane structures, since they are uniquely defined and provide economy of material and more regular fabric patterns. Analytical solution for the non-linear equation governing area minimization may be rather difficult for complex boundaries, leaving numerical solution as the only general way to tackle with the problem. In this paper we show that the dynamic relaxation method offers an interesting alternative to solve the area minimization problem, first interpreted as a nonlinear equilibrium problem, then replaced by a pseudo-dynamic analysis, where fictitious masses and damping matrices are arbitrarily chosen to control the stability of the time integration process

Implementation of a simple wrinkling model into argyris’ membrane finite element

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 modification of the elasticity matrix, according to a projection technique which decompose deformations into elastic and wrinkle components)

Formulaçao de um elemento finito de cabo incorporando o efeito do atrito (Elemento de cabos escorregando)

O trabalho apresenta a formulacáo geometricamente exata e a implementaçao computacional de um elemento finito de cabo que permite o escorregamento em presenca de atrito. O novo elemento fornece procedimentos naturais para simular o processo de montagem e a resposta aos carregamentos de estruturas de cabos em geral, além de ter campos promissores de aplicaçáo no modelamento de estruturas de concreto protendido e no estudo de oscilaçoes auto-excitáveis. Resultados de exemplos elementares sáo discutidos.Peer Reviewe

Direct area minimization through dynamic relaxation

Minimal surfaces, characterized by the property of a minimal area within a fixed boundary, offer an interesting design option for membrane structures, since they are uniquely defined and provide economy of material and more regular fabric patterns. Analytical solution for the non-linear equation governing area minimization may be rather difficult for complex boundaries, leaving numerical solution as the only general way to tackle with the problem. In this paper we show that the dynamic relaxation method offers an interesting alternative to solve the area minimization problem, first interpreted as a nonlinear equilibrium problem, then replaced by a pseudo-dynamic analysis, where fictitious masses and damping matrices are arbitrarily chosen to control the stability of the time integration process

Implementation of a simple wrinkling model into argyris’ membrane finite element

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 modification of the elasticity matrix, according to a projection technique which decompose deformations into elastic and wrinkle components)

Modeling the slippage between membrane and border cables

p. 2059-2070This paper presents the theoretical formulation and the implementation of a class of finite elements capable of representing the slippage between border cables and membrane sheaths, without distortion of the cable's tangent stiffness. After reviewing the 3-node Aufare's sliding-cable element, new sliding-cable super-element is proposed, which simplifies the mesh generation labor and overcomes some limitations of Aufare's elements to deal with large amounts of relative sliding between cables and membrane, which arises as long as meshes are refined.Pauletti, RMO.; Martins, CB. (2010). Modeling the slippage between membrane and border cables. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/726

An overview of the natural force density method and its implementation on an efficient parametric computational framework

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 Programming Language), in the context of parametric modelling. The methods used in the implementation are the Force Density Method (FDM) and the Natural Force Density Method (NFDM), taking advantage of the linear solution approach provided, suitable for fast form-finding computational procedures

Computational Methods for Tension Structures

IASS-IACM 2008 Session: Computational Methods for Tension Structures Session Organizer: SeungDoeg KIM (Semyung University) -- Keynote Lecture: "On the development of general purpose computational program for nonlinear analysis of soft/hard structures" by SeungDeog KIM (Semyung University) -- "Lateral buckling load formulation for multi-strut beam string structures" by Jaeyeol KIM (Hyupsung University), Minger WU (Tongji University) -- "A simple procedure for the analysis of hyperelastic 3D membrane structures" by Vinicius F. ARCARO (UNICAMP, Brazil) -- "Test on the mechanical properties of architectural membrane" by Kang-geun PARK, Seong-kee YOON (Pusan National University), Woo-hong JEON (Korea Apparel Testing & Research Institute) -- Keynote Lecture: "Simplified computer-aided form-finding procedures applied to lightweight structures" by Juan Gerardo OLIVA SALINAS, Eric VALDEZ OLMEDO (UNAM) -- "Shape formation of ETFE film cushion by heat and pressure considering visco-plastic characteristics" by "Masaya KAWABATA, Kaoru NISHIKAWA (Yokohama National University) -- Shape finding of membrane structures by the natural force density method" by Ruy M.O. PAULETTI, Paulo M. PIMENTA (University of Sao Paulo) -- "Topology and shape of tensegrity structures" by Jingyao ZHANG, Makoto OHSAKI (Kyoto University