Deployment behavior control using cables and bi-shape memory alloy convex tape booms

This study aims to demonstrate the synchronous and stable deployment of a newly proposed boom system that consists of cables, a rotary damper, and shape memory alloy with a memorized convex tape shape. Through a shaft, a rotary damper is connected to a reel, and cables wound around the reel are connected to the shape memory alloy boom tips. The deployed part consists of bi-shape memory alloy convex tape booms in which two shape memory alloy convex tapes are combined to form a convex lens cross section, and the outside of the bi-shape memory alloy convex tape is wrapped by a sheet-type heater and polyimide film. The boom is deployed using only the shape recovery force of the shape memory alloy. By installing cables and a rotary damper, the deployment behavior of each boom is controlled, and each boom is deployed synchronously owing to the resistance force of the damper to a leading deploy boom. Moreover, the structural stiffness control concept of the proposed shape memory alloy bi-convex tape boom is discussed considering that Young’s modulus becomes almost half in the martensitic phase

Conceptual model study using origami for membrane space structures : a perspective of origami-based engineering

This paper discusses what has been found and what will be found using conceptual “origami” models to develop deployable space structures. The study covers the following: (i) one-dimensional structural elements, which are axially buckled inflatable tubes; (ii) two-dimensional elements, which are deployable membranes, such as solar arrays and solar sails; and (iii) deployable elements in nature. The study clarifies what design considerations are necessary to adapt the basic concepts to actual space structural hardware, and several limitations of origami models are discussed. Regarding the last subject, this study envisions future space structures using conceptual origami models that imitate three-dimensional deployable structures in nature, such as flowers and insect wings

Deployment Characteristics of Braid Coated Bi-Convex Tape and Bi-SMA Convex Tape Booms for Deployable Membrane Structures

The purpose of this paper is to demonstrate and investigate the concepts of new deployable boom systems, which consist of the BCON (braid coated bi-convex tape) boom and the SMA-BCON (braid coated bi-shape memory alloy convex tape) boom. Both booms are developed for the deployable membrane structures such as solar sails, thin membrane solar array panels, deorbit mechanisms for small satellites and reflectors of space solar power satellite, etc. BCON booms can store around polygonal or cylindrical center hub, and the booms can deploy by the stepwise manner by releasing a constraint mechanism which pins the boons into two or three points for the total length. SMA-BCON booms are mainly developed for a square center body systems, and SMA is adapted on the bent points of the booms where stored around each edge of the center hub. Through the deployment experiments of both booms, the stepwise deployment behavior and its tendency are obtained. The design concept of BCON boom and SMA-BCON boom is demonstrated through this study

Covering Pressure and Friction Effect on Bending Stiffness and Natural Frequency for Braid-coated Biconvex Tape Boom

We investigate the effects of covering pressure and friction between convex tapes on the bending stiffness and natural frequency of a braid-coated biconvex tape (BCON) boom. We establish an analytical model by comparing experimental and analytical results of BCON booms because the braid-coated boundary conditions of the boom are complicated and the analytical model is difficult to construct. BCON booms will have various uses for regular and large-scale deployable space structures such as solar sails, solar array panels, and de-orbit mechanisms. Thus, the bending stiffness, natural frequency, and structural characteristics after deployment are experimentally measured. Several parametric analyses are also calculated by using the proposed contact analysis model. On the basis of these results, we discuss the effect of the braid coating and future work

Numerical Simulation of Stepwise Deployment of Membrane Structure with Booms Using Multi-Particle Approximation Method

Deployable membrane structures are hopeful to develop future lightweight large space structures. In order to predict the dynamic behaviors of the structures in the preliminary design phase, simple and fast numerical simulation is necessary. For this purpose, multi-particle approximation method has been studied which models membranes with spring-mass-damper systems. In this study, polygonal membrane structures integrated with extendible booms are investigated. The membranes are deployed by the elasticity of the booms in a stepwise manner. A multi-particle model for one-dimensional elastic body is introduced as the boom model to the multi-particle method. Each boom is released from the tip end by several particles and the dynamic behaviors of the stepwise deployment can be obtained. The behaviors are compared with deployment experiments of booms without a membrane. Numerical simulation of the deployment of a hexagonal membrane with booms is also demonstrated. Finally, the effect of the stepwise pattern on the vibration motion of the central body due to deployment is studied