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.

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.

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.

Theoretical Analysis and Experimental Investigation on Buckling of FASTMast Deployable Structures

2015 ◽  
Vol 15 (05) ◽  
pp. 1450075 ◽  
Author(s):  
Yulong Jin ◽  
Tao Liu ◽  
Rongxin Lyu ◽  
Bin Ji ◽  
Qifeng Cui
Keyword(s):  
Theoretical Analysis ◽  
Solar Array ◽  
Joint Movement ◽  
Deployable Structures ◽  
Buckling Mode ◽  
Cross Sectional ◽  
Euler Buckling ◽  
Deployable Structure ◽  
Research Findings ◽  
Stiffness Characteristics

FASTMast (Folding Articulated Square Truss Mast) deployable structure is the main bracing structure for the flexible solar array of the international space stations. This study investigates the buckling of FASTMast deployable structures. To this end, the buckling modes and the stiffness characteristics of this structure using the flex batten as an elastic bearing member were theoretically analyzed. The analytical results show that (1) the buckling mode of a FASTMast deployable structure is similar to the elbow joint movement failure when the stiffness of the flex batten is below a critical stiffness value. Once this critical stiffness is reached, the buckling mode takes on the form of Euler buckling. (2) The stiffness of the flex batten is proportional to its cross-sectional second moment of area. Furthermore, an experimental study was carried out to validate the accuracy of the theoretical analysis. The results from experimental work agree fairly well with those from theoretical analysis. The research findings herein are expected to be useful for future studies on similar structures.

Experimental Development of Self-Deployable Structures

1998 ◽  
Vol 13 (3) ◽  
pp. 157-169
Author(s):  
Depankar Neogi ◽  
Craig Douglas ◽  
David R. Smith
Keyword(s):  
Research Effort ◽  
Research Work ◽  
Building Blocks ◽  
The Self ◽  
Structural Element ◽  
Deployable Structures ◽  
Experimental Development ◽  
Deployable Structure ◽  
New Family ◽  
Standing Structure

Deployable space structures are prefabricated structures which can be transformed from a closed, compact configuration to a predetermined expanded form in which they are stable and can bear loads. The present research effort investigates a new family of deployable structures, called self-deployable structures. Unlike other deployable structures, which have rigid members and moving joints, the self-deployable members are flexible while the connecting joints are rigid. The joints store the predefined geometry of the deployed structure in the collapsed state. The self-deployable structure is stress-free in both deployed and collapsed configurations and results in a self-standing structure which acquires its structural properties after a chemical reaction. Reliability of deployment is one of the most important features of the self-deployable structure, since it does not rely on mechanisms that can lock during deployment. The unit building block of these structures is the self-deployable structural element. Several of these elements can be linked to generate more complex building blocks such as a triangular or tetrahedral structures. Different self-deployable structural element and self-deployable structure concepts are investigated in the present research work, and the performance of triangular and tetrahedral prototype structures are experimentally explored.

An Extended Myard Linkage and its Derived 6R Linkage

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Y. Chen ◽  
Z. You
Keyword(s):  
Building Block ◽  
Large Scale ◽  
Deployable Structures ◽  
Deployable Structure ◽  
The Common ◽  
Motion Characteristics ◽  
Flat Profile

In this paper, a 6R linkage suitable as a building block for the construction of large deployable structures is presented. First, we report the possibility of construct an extended 5R Myard linkage by combining two complimentary Bennett linkages. Unlike the original 5R Myard linkage (also called Myard’s “number 1” linkage), the angle of twists in the Bennett linkages is not necessary to be π∕2. Then we show that a 6R linkage can be produced by merging two extended Myard linkages together and removing the common links. The closure equations for the 6R linkage are derived and its motion characteristics are discussed. Moreover, we demonstrate that a number of such 6R linkages can be assembled together to form a large-scale deployable structure, which opens to a flat profile.

scholarly journals A New Flexible Multibody Dynamics Analysis Methodology of Deployable Structures with Scissor-Like Elements

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Qi’an Peng ◽  
Sanmin Wang ◽  
Changjian Zhi ◽  
Bo Li
Keyword(s):  
Multibody Dynamics ◽  
Flexible Multibody Dynamics ◽  
Dynamics Analysis ◽  
Deployable Structures ◽  
Constraint Equations ◽  
Deployable Structure ◽  
Analysis Methodology ◽  
Flexible Multibody ◽  
Nodal Coordinates ◽  
Element Characteristic

Abstract There are vast constraint equations in conventional dynamics analysis of deployable structures, which lead to differential-algebraic equations (DAEs) solved hard. To reduce the difficulty of solving and the amount of equations, a new flexible multibody dynamics analysis methodology of deployable structures with scissor-like elements (SLEs) is presented. Firstly, a precise model of a flexible bar of SLE is established by the higher order shear deformable beam element based on the absolute nodal coordinate formulation (ANCF), and the master/slave freedom method is used to obtain the dynamics equations of SLEs without constraint equations. Secondly, according to features of deployable structures, the specification matrix method (SMM) is proposed to eliminate the constraint equations among SLEs in the frame of ANCF. With this method, the inner and the boundary nodal coordinates of element characteristic matrices can be separated simply and efficiently, especially on condition that there are vast nodal coordinates. So the element characteristic matrices can be added end to end circularly. Thus, the dynamic model of deployable structure reduces dimension and can be assembled without any constraint equation. Next, a new iteration procedure for the generalized-α algorithm is presented to solve the ordinary differential equations (ODEs) of deployable structure. Finally, the proposed methodology is used to analyze the flexible multi-body dynamics of a planar linear array deployable structure based on three scissor-like elements. The simulation results show that flexibility has a significant influence on the deployment motion of the deployable structure. The proposed methodology indeed reduce the difficulty of solving and the amount of equations by eliminating redundant degrees of freedom and the constraint equations in scissor-like elements and among scissor-like elements.

Planar Deployable Linkage and Its Application in Overconstrained Lift Mechanism

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
Dong-Jie Zhao ◽  
Jing-Shan Zhao ◽  
Zheng-Fang Yan
Keyword(s):  
Screw Theory ◽  
Load Capacity ◽  
Stress Conditions ◽  
Central Axis ◽  
Deployable Structures ◽  
Deployable Structure ◽  
Prototype Test ◽  
Lift Mechanism ◽  
Moving Platform

This paper investigates the application of a planar deployable structure with screw theory and discusses its possible applications in overconstrained lift platforms via calculating its stiffness. These platforms are all made up of a number of identical scissor-form pivoted links. Compared with their traditional counterparts, the lift platforms with planar deployable structures have higher stiffness and higher strength in applications because every lift platform is multiplane overconstrained mechanism connected by a strengthened frame at each deployable layer. In operation, these deployable structures are always symmetric about the vertical central axis connecting the moving platform and the fixed one. Therefore, the stress conditions of the links in each layer can be assumed to be identical as the lift platform is moving up and down. Prototype test illustrates the innovation of the lift mechanisms while keeping the same load capacity.

scholarly journals Analysis and control of state jump in space deployable structures under alternating temperature loads

2021 ◽  
Vol 12 (1) ◽  
pp. 59-67
Author(s):  
Congcong Chen ◽  
Tuanjie Li ◽  
Yaqiong Tang ◽  
Zuowei Wang
Keyword(s):  
Influence Factors ◽  
Stable State ◽  
Variable Stiffness ◽  
Equivalent Model ◽  
Deployable Structures ◽  
Deployable Structure ◽  
Structure Changes ◽  
Alternating Temperature ◽  
Space Deployable Structures ◽  
And Control

Abstract. State jump has been experimentally observed in space deployable structures working in alternating temperature environments. State jump is a phenomenon in which the geometric shape of the structure changes after the temperature loading and unloading process, which makes the working accuracy of the space deployable structure intrinsically unpredictable. This paper aims to investigate the causes of this state jump phenomenon and seek measures to reduce its effect. Firstly, the static multiple-stable-state phenomenon resulting in state jump is analyzed for clearance joints in deployable structures. Then, an equivalent model consisting of a variable stiffness spring and a contact element for state jump analysis is proposed, which is verified by a finite element simulation. Influence factors and control methods of state jump are further explored. Finally, numerical results of a space deployable structure of an umbrella-shaped antenna show the effectiveness of the developed analytical method.

Compact Directional and Frictional Hinges for Flat Folding Applications

2018 ◽  
Author(s):  
Patrick D. Shemenski ◽  
Brian P. Trease
Keyword(s):  
Complex Shape ◽  
Compliant Mechanisms ◽  
Deployable Structures ◽  
Packing Factor ◽  
Deployable Structure ◽  
The Creation

Thick-rigid deployable origami structures make use of compliant mechanisms to create folds and hinging surfaces. This paper examines the potential types of compact directional and frictional hinges to supplement the usage of compliant mechanisms in flat-folding applications. Rigid motioncontrolling hinges offer many opportunities to deployable origami. Hinges, in the form of hard stops, ratchets, or spring detents can allow for complex shape generation through kinematic manipulation. Hinged origami lends itself well to the creation of origami robotics, deployable structures, and arrays. With the ability to offer a high packing factor and create a self-supporting deployable structure, further research should be conducted into the application and development of hinged origami.

scholarly journals Dynamics Analysis of Deployable Structures considering a Two-Dimensional Coupled Thermo-Structural Effect

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Qi’an Peng ◽  
Sanmin Wang ◽  
Bo Li ◽  
Changjian Zhi ◽  
Jianfeng Li
Keyword(s):  
Optimization Design ◽  
Control Process ◽  
Axial Direction ◽  
Structural Effect ◽  
Dynamics Analysis ◽  
Two Dimensional ◽  
Deployable Structures ◽  
One Dimensional ◽  
Deployable Structure ◽  
Deployment Dynamics

The deployment accuracy of deployable structures is affected by temperature and flexibility. To obtain the higher accuracy, various measures such as the optimization design and the control process are employed, and they are all based on deployment dynamics characteristics of deployable structures. So a precise coupled thermo-structural deployment dynamics analysis is important and necessary. However, until now, only a one-dimensional thermal effect is considered in the literatures because of simplicity, which reduces the accuracy of the model. Therefore, in this paper, a new model coupling mechanical field with a temperature field is presented to analyze the deployment dynamics of a deployable structure with scissor-like elements (SLEs). The model is based on the absolute nodal coordinate formulation (ANCF) and is established via a new locking-free beam element whose formulation is extended to account for the two-dimensional thermally induced stresses due to the heat expansion for the first time. Namely, in the formulation, the thermal influences are along two-dimensional directions, the axial direction and the transverse direction, rather than along a one-dimensional direction. The validity and precision of the proposed model are verified using a flexible pendulum example. Finally, the dynamics of a linear deployable structure with three SLEs modeled by the element is simulated under a temperature effect.

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