Design methods for planar and spatial deployable structures

Download

index.pdf

Date

2011

Author

Kiper, Gökhan

Metadata

Show full item record

Item Usage Stats

226
views

426
downloads

This thesis study addresses the problem of overconstraint via introduction of conformal polyhedral linkages comprising revolute joints only and investigation of special geometric properties for the mobility of such overconstrained linkages. These linkages are of particular interest as deployable structures. First, planar case is issued and conditions for assembling irregular conformal polygonal linkages composed of regular and angulated scissor elements are derived. These planar assemblies are implemented into faces of polyhedral shapes and radially intersecting planes to obtain two different kind of polyhedral linkages. Rest of the thesis work relates to spatial linkages. Identical isosceles Bennett loops are assembled to obtain regular polygonal linkages and many such linkages are assembled to form polyhedral linkages. Then, Fulleroid-like linkages are presented. After these seemingly independent linkage types, Jitterbug-like linkages are introduced. Based on some observations on present linkages in the literature a definition for Jitterbug-like linkages is given first, and then a set of critical properties of these linkages are revealed. This special type of polyhedral linkages is further classified as being homothetic and non-homothetic, and geometric conditions to obtain mobile homothetic Jitterbug-like polyhedral linkages are investigated. Homohedral linkages, linkages with polyhedral supports with 3- and 4-valent vertices only, tangential polyhedral linkages are detailed as special cases and the degenerate case where all faces are coplanar is discussed. Two types of modifications on Jitterbug-like linkages are presented by addition of links on the faces and radial planes of Jitterbug-like linkages. Finally, a special class of Jitterbug-like linkages - modified Wren platforms are introduced as potential deployable structures.

Subject Keywords

Polyhedral functions., Structural design.

URI

http://etd.lib.metu.edu.tr/upload/12613519/index.pdf
https://hdl.handle.net/11511/21175

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Nonlinear Structural Coupling: Experimental Application Kalaycioglu, Taner; Özgüven, Hasan Nevzat (2014-02-06) In this work, the nonlinear structural modification/coupling technique proposed recently by the authors is applied to a test system in order to study the applicability of the method to real structures. The technique is based on calculating the frequency response functions of a modified system from those of the original system and the dynamic stiffness matrix of the nonlinear modifying part. The modification can also be in the form of coupling a nonlinear system to the original system. The test system used i...
Modeling of the nonlinear behavior of steel framed structures with semi rigid connections Sarıtaş, Afşin; Özel, Halil Fırat (null; 2015-07-21) A mixed formulation frame finite element with internal semi-rigid connections is presented for the nonlinear analysis of steel structures. Proposed element provides accurate responses for spread of inelasticity along element length by monitoring the nonlinear responses of several crosssections, where spread of inelasticity over each section is captured with fiber discretization. Each material point on the section considers inelastic coupling between normal stress and shear stress. The formulation of the ele...
Layout optimisation of trusses using simulated annealing Hasançebi, Oğuzhan (2002-07-01) This paper addresses to the development of a simulated annealing (SA) based solution algorithm for the simultaneous optimum design of truss type structures with respect to size, shape and topology design variables. The proposed algorithm is designed in such way that together with applicability to practical design problems, it also aims to produce efficient and improved design solutions for the problems of interest. From the practical point of view, the objective chosen is to minimise the weight of the struc...
Numerical integration of a class of 3d plastic-damage concrete models and condensation of 3d stress-strain relations for use in beam finite elements Sarıtaş, Afşin (Elsevier BV, 2009-10-01) This paper presents a method for the integration of a class of plastic-damage material models. The integration of the evolution equations results in a nonlinear problem, which is linearized and solved with the Newton-Raphson method using a sub-stepping strategy. The consistent tangent matrix can be formulated either in terms of the stress components in a general reference system or in terms of the principal stress and strain components with the former then transformed to the general reference system. In ord...
Layout optimization of trusses using simulated annealing Hasançebi, Oğuzhan (2000-09-08) This paper addresses to the development of a simulated annealing (SA) based solution algorithm which is automated to achieve the simultaneous optimum design of truss type structures with respect to size, shape and topology design variables. The proposed algorithm is designed in such a way that together with applicability to practical design problems, it is also aimed at producing efficient and improved design solutions for the problems of interest. From the practicality point of view, the task is chosen as ...

Citation Formats

G. Kiper, “Design methods for planar and spatial deployable structures,” Ph.D. - Doctoral Program, Middle East Technical University, 2011.