Auxetic shape memory alloy cellular structures for deployable satellite antennas: design, manufacture and testing

Abstract

Abstract. We describe the production development and experimental tests related to an hybrid honeycomb-truss made of shape memory alloy (Ni48Ti46Cu6), and used as a demonstrator for a deployable antenna in deep-space missions. Specific emphasis is placed on the modal analysis techniques used to test the lightweight SMA structure.. Background on SMA cellular structuresShape memory alloy (SMA) can be considered amongst the most successful smart materials to date in terms of spread of applications, and relative maturity of the technology. We do not aim in this work to provide an extensive review on the SMA field, however the interested reader can look for reference [1] for a detailed introduction on the subject. However, SMA honeycombs constitute a more recent development, being proposed by some of the Authors for the first time in 2004 at the SPIE Smart Materials and Structure Conference in San Diego, CA. Hassan, Scarpa and Mohammed [2] developed a OX (overexpanded) hexagonal honeycomb cold moulding some 1-way SMA ribbons, and gluing the hexagonal shapes obtained with a high temperature epoxy-based polymer. Almost at the same time, Shaw et al at the University of Michigan developed a patented assembling technique based on welding niobium rods, which allows producing small cellular samples with high manufacturing fidelity (i.e., low dimensional and precision tolerances) [3]. Prototypes of SMA honeycombs made with a similar welding techniques have been also manufactured and sandwich within composite face skins at the University of Tokyo. The sandwich panels subjected to low kinetic energy impacts and subsequent heating from martensite to austenite phase showed one of the main features for which SMA cellular structures have been developed -the capability of absorbing energy, and restoring (in a significant percentage) the original shape after impact [4]. Another interesting feature of SMA based honeycombs is also their intrinsic high hysteretic damping, 2-3 orders of magnitude higher than the commercial aluminium or steel-based honeycombs used in high end aerospace applications subjected to high cyclic fatigue loading or broadband vibration input [5].The cellular structures considered so far have a centresymmetric topology -I.e., two perpendicular axis of symmetry. However, it is possible also to adopt a rotational-type of symmetry, which provides a combined in-plane rotation and translational deformation when subjected to inplane uniaxial loading, and feature also a negative Poisson's ratio behaviour. This structure, called hexagonal chiral topology, has been proposed as load-bearing concept by Prall and Lakes in 1996 [6], although the idea of negative Poisson's ratio in chiral-related structures was first devised by Wojciechowski for molecular assemblies [7]. The Poisson's ratio of this cellular structure is close to

Comparative study of auxetic geometries by means of computer-aided design and engineering

“…Auxetic geometries are being progressively employed in the development of novel products, especially in the fields of intelligent expandable actuators, shape morphing structures and minimally invasive implantable devices. Regarding smart actuators based on an auxetic structure, it is important to cite some recent progress linked to auxetic shape-memory alloys (SMA) for developing deployable satellite antennas [6] and some research on the characterization of polyurethane foams with shape-memory behavior and auxetic properties, promoted thanks to several post-processing stages [7]. In the area of medical devices, recent research has also assessed the behavior of a few auxetic geometries for implementing expandable stents [8] and their application to other implantable biodevices is clearly a matter of research.…”

Geometric Study of Two-Dimension Stellated Reentrant Auxetic Structures to Transformable Architecture

“…Minimally invasive implantable devices, morphological structures of the forms and smart expandable actuators are the main areas of application [6] . Devices utilized for the development of drop-down satellite antennas like shape memory auxetics alloys (SMA) also exist [7] . They are based on auxetic patterns and they are utilized as intelligent actuators.…”

Experimental investigation on the dynamic mechanical properties of soft magnetic entangled metallic wire material

“…Considering the tunable mechanical properties of shape memory alloy [9,10], i.e. its elastic modulus has a temperature dependency and heat treatment effects due to the shape memory effect of entangled nitinol wires [11], the idea of smart EMWM has been firstly realized by the using of shape memory alloy wires [12][13][14]. However their response to environmental temperature change is relatively slow, which limits their practical use in the field of active vibration control.…”