Geometric Analysis of a Modular, Deployable and Reusable Structure

2019 ◽  
Vol 805 ◽  
pp. 155-160 ◽  
Author(s):  
F. Ama Gonzalo ◽  
Mariano Molina ◽  
Covadonga Lorenzo ◽  
M.I. Castilla ◽  
Pulido D. Gomez ◽  
...  
Keyword(s):  
Geometric Analysis ◽  
Maximum Length ◽  
Structural Behavior ◽  
Deployable Structures ◽  
Deployable Structure ◽  
Wide Range ◽  
Post Tensioning ◽  
Expanded Form

The use of deployable structures has a wide range of applications nowadays. They can be transformed from a closed compact configuration to a predetermined expanded form, in which they are stable and can carry loads. This article describes a sort of deployable structure that has been patented by researchers of two Spanish institutions: San Pablo CEU University and Eduardo Torroja Institute. Geometric aspects are key to accomplish an efficient folding and unfolding procedure along with an optimum structural behavior when the structure is deployed. Tensioned cables are essential in these structures. The main goal is to make the cable acquire its maximum length when the structure is fully deployed. This will avoid complex operations of post-tensioning in order to make the cable perform its function.

A Study of New Deployable Structure

2014 ◽  
Vol 1049-1050 ◽  
pp. 1083-1089
Author(s):  
Yi Jie Song ◽  
Chi On Ho ◽  
Zi Fei Qing
Keyword(s):  
Aluminum Alloy ◽  
Numerical Analysis ◽  
Vertical Load ◽  
Test Program ◽  
Deployable Structures ◽  
Deployable Structure ◽  
Out Of Plane ◽  
Comprehensive Evaluations ◽  
The Stability ◽  
Expanded Form

Deployable structures are new prefabricated frames that can be transformed from a closed stage or compact configuration to a predetermined, stable expanded form. The structure is very convenient for transportation and recycling because it can be stretched out, drawn back and disassembled into pieces easily. This paper describes a new deployable structure composed of scissor composite members, each of which consists of universal scissor components, connected by bolts, and braced by pre-tensioned ropes out-of-plane, conforming a stable system. An aluminum-alloy deployable model was fabricated and a test program was carried out under vertical load to evaluate the capacity of the structure. Numerical analysis using FEM was conducted for validation purpose. By studying the stability and capacity of the structure, comprehensive evaluations of the structure were made. Possessing several advantages stated in this paper, deployable structures can be used as semi-permanent and temporary large spatial buildings.

Geometry and Physics: Volume II

2018 ◽  
Keyword(s):  
Moduli Spaces ◽  
Mirror Symmetry ◽  
Geometric Analysis ◽  
Mathematical Physics ◽  
Poisson Geometry ◽  
Special Holonomy ◽  
Low Dimensional Topology ◽  
Generalized Complex Structures ◽  
Wide Range ◽  
Low Dimensional

These volumes contain the proceedings of the conference held at Aarhus, Oxford and Madrid in September 2016 to mark the seventieth birthday of Nigel Hitchin, one of the world’s foremost geometers and Savilian Professor of Geometry at Oxford. The proceedings contain twenty-nine articles, including three by Fields medallists (Donaldson, Mori and Yau). The articles cover a wide range of topics in geometry and mathematical physics, including the following: Riemannian geometry, geometric analysis, special holonomy, integrable systems, dynamical systems, generalized complex structures, symplectic and Poisson geometry, low-dimensional topology, algebraic geometry, moduli spaces, Higgs bundles, geometric Langlands programme, mirror symmetry and string theory. These volumes will be of interest to researchers and graduate students both in geometry and mathematical physics.

A Tailored Nonlinear Slat-Cove Filler for Airframe Noise Reduction

2018 ◽  
Author(s):  
Gaetano Arena ◽  
Rainer Groh ◽  
Alberto Pirrera ◽  
William Scholten ◽  
Darren Hartl ◽  
...  
Keyword(s):  
High Strain ◽  
Interaction Analysis ◽  
Effective Means ◽  
Leading Edge ◽  
Structural Behavior ◽  
Deployable Structures ◽  
Airframe Noise ◽  
Structure Interaction ◽  
Slat Noise ◽  
Displacement Constraints

Exploiting mechanical instabilities and elastic nonlinearities is an emerging means for designing deployable structures. This methodology is applied here to investigate and tailor a morphing component used to reduce airframe noise, known as a slat-cove filler (SCF). The vortices in the cove between the leading edge slat and the main wing are among the important sources of airframe noise. The concept of an SCF was proposed in previous works as an effective means of mitigating slat noise by directing the airflow along an acoustically favorable path. A desirable SCF configuration is one that minimizes: (i) the energy required for deployment through a snap-through event; (ii) the severity of the snap-through event, as measured by kinetic energy, and (iii) mass. Additionally, the SCF must withstand cyclical fatigue stresses and displacement constraints. Both composite and shape memory alloy (SMA)-based SCFs are considered during approach and landing maneuvers because the deformation incurred in some regions may not demand the high strain recoverable capabilities of SMA materials. Nonlinear structural analyses of the dynamic behavior of a composite SCF are compared with analyses of similarly tailored SMA-based SCF and a reference, uniformly thick superelastic SMA-based SCF. Results show that by exploiting elastic nonlinearities, both the tailored composite and SMA designs decrease the required actuation energy compared to the uniformly thick SMA. Additionally, the choice of composite material facilitates a considerable weight reduction where the deformation requirement permits its use. Finally, the structural behavior of the SCF designs in flow are investigated by means of preliminary fluid-structure interaction analysis.

Annular Post-Compression by FRP inside Mortar Joints and Vertical Post-Compression by Stainless Steel, for Seismic and Wind Retrofitting of Historical Masonry Chimney

2019 ◽  
Vol 817 ◽  
pp. 642-649
Author(s):  
Alberto Viskovic ◽  
Libbio Antonelli ◽  
Filippo Morgante
Keyword(s):  
Stainless Steel ◽  
Structural Behavior ◽  
Case Study Approach ◽  
Study Approach ◽  
Safety Improvement ◽  
Inside Face ◽  
Historical Masonry ◽  
Post Tensioning ◽  
Central Void

This paper shows the efficiency of the vertical and annular post-compression for wind and seismic structural behavior improvement of slender masonry chimney. For this aim a case study approach regarding an old masonry chimney is used. The paper shows the safety analysis and the safety improvement obtained applying at the same time a vertical and an annular masonry post-compression. The vertical post-compression is obtained through the post-tensioning of twenty-four vertical stainless-steel thin bars. These bars are connected to the chimney masonry only at the basement and at the top. They are placed inside the central void and horizontally distributed along a circumference near the inside face of the masonry, but without to touch it. The annular post-compression is obtained post-tensioning forty-five annular aramidica “not twisted” cables, placed and glued (after the post-tensioning) inside horizontal mortar joints of the more external masonry brick layer.

Geometry and Physics: Volume I

2018 ◽  
Keyword(s):  
Moduli Spaces ◽  
Mirror Symmetry ◽  
Geometric Analysis ◽  
Mathematical Physics ◽  
Poisson Geometry ◽  
Special Holonomy ◽  
Low Dimensional Topology ◽  
Generalized Complex Structures ◽  
Wide Range ◽  
Low Dimensional

These volumes contain the proceedings of the conference held at Aarhus, Oxford and Madrid in September 2016 to mark the seventieth birthday of Nigel Hitchin, one of the world’s foremost geometers and Savilian Professor of Geometry at Oxford. The proceedings contain twenty-nine articles, including three by Fields medallists (Donaldson, Mori and Yau). The articles cover a wide range of topics in geometry and mathematical physics, including the following: Riemannian geometry, geometric analysis, special holonomy, integrable systems, dynamical systems, generalized complex structures, symplectic and Poisson geometry, low-dimensional topology, algebraic geometry, moduli spaces, Higgs bundles, geometric Langlands programme, mirror symmetry and string theory. These volumes will be of interest to researchers and graduate students both in geometry and mathematical physics.

Integrity of Longitudinal Welds in Pipelines: Bridging Scales

2018 ◽  
Author(s):  
Marion Erdelen-Peppler ◽  
Christoph Kalwa ◽  
Jens Schröder
Keyword(s):  
Circumferential Stress ◽  
Ring Expansion ◽  
Structural Behavior ◽  
Single Edge ◽  
Crack Tip Opening Displacement ◽  
Single Edge Notch ◽  
Wide Range ◽  
Edge Notch ◽  
Longitudinal Welds ◽  
The Impact

Toughness testing of the heat affected zone (HAZ) of longitudinal welds is increasingly often required in pipeline standards and specifications. This includes simple tests such as the Charpy impact test that was designed to serve as quality test as well as enhanced methods including crack tip opening displacement (CTOD) tests that are necessary to conduct an engineering critical assessment (ECA). If occasional low toughness values are observed, the question turns towards assessing the impact of such numbers and how representative they are of the behavior of a pipe in service. The significance of low toughness values measured in laboratory testing can be judged on basis of ring expansion and hydraulic burst tests. The current study summarises an extensive test series to quantify the toughness of submerged arc welds (SAW) obtained by different test methods. The tested pipes cover a wide range of material including medium strength X70 up to high strength X100. Their welds are characterized in terms of fracture toughness properties with single edge notch tension (SENT) and single edge notch bending (SENB) tests. Different constraint levels are obtained within each series by introducing notches of standard depth as well as shallow notches. Structural behavior is characterized with burst tests as well as ring expansion tests containing notches in the longitudinal weld. The experimental results are assessed within dedicated finite element studies. The assessment is conducted for pipes serving as pressure containment, thus having circumferential stress resulting from internal pressure. Based on the results achieved the conclusion can be drawn that the standard route including high constraint CTOD leads to overly conservative results concerning the integrity of longitudinal welds. A better representation of structural behavior is observed in ring expansion tests.

On mobile assemblies of Bennett linkages

2008 ◽  
Vol 464 (2093) ◽  
pp. 1275-1293 ◽  
Author(s):  
Y Chen ◽  
Z You
Keyword(s):  
Deployable Structures ◽  
Single Degree ◽  
Deployable Structure ◽  
The One ◽  
Cylindrical Profile

This paper deals with deployable structures formed by interconnected Bennett linkages. A total of eight cases that allow mobile assemblies of Bennett linkages being built have been found by considering the links that may contain sections with negative length. Among the eight assemblies, four are distinct ones, including the one that we reported previously, and the remaining can be obtained by modifying the four cases. All these assemblies consist of a grid of nested Bennett linkages. The layout of the assemblies can be repeated to form a large deployable structure. When the Bennett linkages are equilateral, the assemblies expand to form arches. For a non-equilateral case, the assemblies deploy into a helical shape with a cylindrical profile. They are geometrically overconstrained with a single degree of mobility. The newly found assemblies provide more choices in the design of deployable structures.

Active Moving Polymers and Multifunctional Composites: Shape the Future Structures

2013 ◽  
Vol 745 ◽  
pp. 129-134 ◽  
Author(s):  
Jin Song Leng
Keyword(s):  
Smart Materials ◽  
Biomedical Engineering ◽  
Composite Structures ◽  
Shape Memory Polymer ◽  
Multifunctional Composites ◽  
Deployable Structures ◽  
Wide Range ◽  
Space Deployable Structures ◽  
Short Carbon

Smart materials can be defined as the materials that have the capability of sensing and reacting to environmental conditions or stimuli. In recent years, a wide range of novel smart materials have been developed, the applications of which now cover various important fields including aerospace, automobile, telecommunications, and so forth. This talk mainly focuses on recent progresses of Active Moving Polymer (i.e. Shape Memory Polymer, SMP), and SMP based composite structures, as well as their applications including aerospace, astronautics and biomedical engineering. This presented work summarizes the recent advances in novel SMP including epoxy-based SMP, styrene-based SMP, cyanate ester-based SMP, polyurethane-based SMP, multiple SMP, design and characterization of SMP composites (SMPCs) filled with nickel chains, short carbon fiber, carbon nanotube chains, carbon nanopaper, and so on. The SMP stimulus methods, including heat, electric, light, magnetic field, and solvent have been introduced. The application of SMPCs used in aircraft morphing and space deployable structures is also investigated.

The influence of joint eccentricity on the foldability of four deployable structure systems

2021 ◽  
pp. 095605992110484
Author(s):  
Adolfo Pérez-Egea ◽  
Pedro García Martínez ◽  
Martino Peña Fernández-Serrano ◽  
Pedro Miguel Jiménez Vicario ◽  
Manuel Alejandro Ródenas-López
Keyword(s):  
Tube Bundle ◽  
Deployable Structures ◽  
Deployable Structure ◽  
Constituent Elements

The study of deployable structures has been carried out traditionally by simplifying their constituent elements—joints and rods—to ideal entities. However, in this paper the dimensional thickness of these elements is taken into account, in order to evaluate their incidence on the foldability of four deployable structure systems. We have examined the eccentricity that occurs specifically at the joints themselves. Our study ultimately characterizes the incidence of this factor by defining noteworthy parameters common to both tube bundle and scissor systems, enabling us to establish a comparison and draw relevant conclusions.

NON-UNIFORM RATIONAL B-SPLINE BASED ISO-GEOMETRIC ANALYSIS FOR A CLASS OF HYDRODYNAMIC PROBLEMS

2021 ◽  
Vol 162 (A2) ◽  
Author(s):  
M Goel ◽  
R Sharma ◽  
S K Bhattacharyya ◽  
Tae-wan Kim
Keyword(s):  
Boundary Value Problems ◽  
Potential Function ◽  
Computational Efficiency ◽  
Boundary Value ◽  
Geometric Analysis ◽  
Geometric Approach ◽  
Panel Method ◽  
B Spline ◽  
Computational Performance ◽  
Wide Range

Herein, we present the design and development of a ‘Non-uniform Rational B-spline (NURBS)’ based iso-geometric approach for the analysis of a number of ‘Boundary Value Problems (BVPs)’ relevant in hydrodynamics. We propose a ‘Potential Function’ based ‘Boundary Element Method (BEM)’ and show that it holds the advantage of being computationally efficient over the other known numerical methods for a wide range of external flow problems. The use of NURBS is consistent, as inspired by the ‘iso-geometric analysis’, from geometric formulation for the body surface to the potential function representation to interpolation. The control parameters of NURBS are utilised and they have been explored to arrive at some preferable values and parameters for parameterization and the knot vector selection. Also, the present paper investigates the variational strength panel method, and its computational performance is analyzed in comparison with the constant strength panel method. The two variations have been considered, e.g. linear and quadratic. Finally, to illustrate the effectiveness and efficiency of the proposed NURBS based iso-geometric approach for the analysis of boundary value problems, five different problems (i.e. flow over a sphere, effect of the knot vector selection on analysis, flow over a rectangular wing section of NACA 0012 aerofoil section, performance of DTMB 4119 propeller (un-skewed), performance of DTNSDRC 4382 propeller (skewed)) are considered. The results show that in the absence of predominant viscous effects, a ‘Potential Function’ based BEM with NURBS representation performs well with very good computational efficiency and with less complexity as compared to the results available from the existing approaches and commercial software programs, i.e. low maximum errors close to 110−3 , faster convergence with even up to 75 % reduction in the number of panels and improvements in the computational efficiency up to 32.5 % even with low number of panels.

Sign in / Sign up

Export Citation Format

Share Document