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... that the axes of the hinges in each side of the frame are perpendicular to that side and all hinges are coplanar; the corners of the frame are rigid, i.e. there are no hinges. All hinges would be self-locking hinges, e.g. of the type shown in Figure 3.7. ...
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... the transverse hinges are activated to Z-fold the structural longitudinally. The whole sequence can be visualised by following in reverse the sequence in Figure 3.2. Because of the small thickness of the panels, it is not difficult to arrange the hinges between the panels to permit this bi-axial folding. ...
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... model, shown in Figure 3.3, consists of a 0.98 (0.85 on the shorter side)×0.7 m 2 timber frame, made from 25×32 mm 2 rectangular section members connected by brass hinges, to which a thin foil has been attached with double-sided adhesive tape. ...
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... that, whereas the hinges that allow Z-folding of the longitudinal members are surface- mounted, the hinges in the transverse members are mounted half-way through the thickness Figure 3.3: Deployment of model structure. ...
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... changing the configuration of the TSR hinges in the transverse members, the same model can be used to produce the trough configuration already seen in Figure 3.1(b). This is shown in ...
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... first analysis was carried out for members with outer diameter (o.d.) of 25 mm and 1 mm wall thickness (I = 5438 mm 4 ). The mode shapes for the structure with TSR hinges are shown in Figure 3.5. Note that the first two modes, at 0.44 and 0.60 Hz, involve out-of-plane bending and in-plane shearing of the frame. ...
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... corresponding mode shapes, for the frame with TSR hinges, can be seen in Figure 3.6. In this analysis the fundamental natural frequency of the TSR hinge frame is approaching 1 Hz, however the stiff hinge model shows a fundamental natural frequency significantly over 1 Hz indicating that the flexibility of the frame arises primarily from the flexibility of the hinges. ...
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... CFRP tubes with 25 mm o.d. and wall thickness of 1 mm, as before, were used all around and the frame was analysed assuming either TSR hinges or built-in connections between the members. The first four mode shapes of the frame with TSR hinges can be seen in Figure 3.8 and the natural frequencies are compared in Table 3.4 to the corresponding frequencies of the rigidly-jointed frame. ...
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Citations
... Space antennas play an indispensable role in the aerospace communication, military reconnaissance, deep-space probes, global broadcasting, remote sensing and climate forecasting. Due to the volume and weight constraints of launch vehicles, the deployable antennas are widely used for their easy storage and transportation [1][2][3]. They are stowed in the fairing at the launch stage, and then start to deploy after entering the orbit and finally form the parabolic reflective surfaces. ...
... Space antennas play an indispensable role in the aerospace communication, military reconnaissance, deep-space probes, global broadcasting, remote sensing and climate forecasting. Due to the volume and weight constraints of launch vehicles, the deployable antennas are widely used for their easy storage and transportation [1][2][3]. They are stowed in the fairing at the launch stage, and then start to deploy after entering the orbit and finally form the parabolic reflective surfaces. ...
Mesh reflector antennas have been widely used in space satellites for their characteristics of large aperture, low levels of total mass, stowed volume, surface distortion, etc. The antenna turns from a stowed state to a fully deployed configuration and finally forms a required functional surface, and this deployment process affects the performances of antennas on orbit. The dynamic modeling and analysis for the deployment of mesh reflector antennas considering the rigid body rotation of rods, the geometric nonlinearity of the cable net, and the rigid-flexible coupling of the truss and the cable net are presented in this paper. Instead of the previous lumped mass model, the mass of hinges is concentrated on their centroids and the longerons, battens, and diagonals are regarded as homogeneous rods in the study. By this model, the rigid body motion of rods can be well considered in the calculation of kinetic energies rather than be ignored in previous researches. Then, the cable net is discretized into multiple cable elements that are modeled by springs. The slacked and tensioned state of cable elements during deployment are captured by updating the stiffness matrix real-timely. The elastic energy of the cable net is derived by solving systematic equilibrium equations. The dynamic model is established by using Lagrange equation, and then the driving force under the predesigned motion is derived. The “ideal deployment motion” and “feasible deployment motion” are proposed and discussed through several numerical examples. Simulation results match well with experimental data in previous literature.
... Deployable aperture concepts for small satellites, e.g. 700×700×700 mm 3 , with limited volume for appendages were investigated by Pellegrino [13] et al. and the reflector antenna concept was further developed by Tibert [14] . For nanosatellites, e.g. the CubeSat satellite platform (100×100×100 mm 3 ), the volume constraints are very hard to meet with traditional designs, Murphey [11] , and self-deploying concepts for booms and apertures are emerging as viable alternatives to meet requirements on both volume and power (Stiles [15] ). ...
In this paper we describe a tensegrity ring of innovative conception for deployable space antennas. Large deployable space structures are mission-critical technologies for which deployment failure cannot be an option. The difficulty to fully reproduce and test on ground the deployment of large systems dictates the need for extremely reliable architectural concepts. In 2010, ESA promoted a study focused on the pre-development of breakthrough architectural concepts offering superior reliability. This study, which was performed as an initiative of ESA Small Medium Enterprises Office by Kayser Italia at its premises in Livorno (Italy), with Università di Roma TorVergata (Rome, Italy) as sub-contractor and consultancy from KTH (Stockholm, Sweden), led to the identification of an innovative large deployable structure of tensegrity type, which achieves the required reliability because of a drastic reduction in the number of articulated joints in comparison with non-tensegrity architectures. The identified target application was in the field of large space antenna reflectors. The project focused on the overall architecture of a deployable system and the related design implications. With a view toward verifying experimentally the performance of the deployable structure, a reduced scale breadboard model was designed and manufactured. A gravity off-loading system was designed and implemented, so as to check deployment functionality in a 1-g environment. Finally, a test campaign was conducted, to validate the main design assumptions as well as to ensure the concept’s suitability for the selected target application. The test activities demonstrated satisfactory stiffness, deployment repeatability, and geometric precision in the fully deployed configuration. The test data were also used to validate a finite element model, which predicts a good static and dynamic behavior of the full-scale deployable structure.
... Deployable aperture concepts for small satellites, e.g. 700×700×700 mm 3 , with limited volume for appendages were investigated by Pellegrino [13] et al. and the reflector antenna concept was further developed by Tibert [14] . For nanosatellites, e.g. the CubeSat satellite platform (100×100×100 mm 3 ), the volume constraints are very hard to meet with traditional designs, Murphey [11] , and self-deploying concepts for booms and apertures are emerging as viable alternatives to meet requirements on both volume and power (Stiles [15] ). ...
... In response to these requirements, three novel deployable structures, related to categories 2 and 3 above, were developed. These are presented in reference [130]. In that study, the author was involved in the development of a 3 m diameter parabolic reflector SAR. ...
... The preliminary study of the SAR reflector antenna, performed by Pellegrino and the author, is presented in references [130] and [169]. This study will now be significantly 100 expanded. ...
... It is observed that the mass limit of 20 kg, set up by DERA, is easily achieved by the present antenna at 6.67 kg or 1. 24 cf. [130], the reflector antenna is superior. Comparing the areal densities of the mesh antennas in Table 2.1, which vary between 0.36 and 4.58 kg/m 2 , the present value is amongst the best. ...
... The latter solution is easier to quantify at the present time and so a preliminary mass estimate was obtained by considering the mass of recently developed demonstrator hardware. The tape-spring-rolamite hinges developed by Pellegrino et al. (2000) have a total mass, including attachments to the struts, of 0.2 kg. For the end connections between the strut and the ring structure cables a mass of 0.1 kg per strut was assumed. ...
A new concept for deployable mesh reflectors is pre- sented. It consists of a deployable ring structure and two identical cable nets (front and rear nets) connected by ten- sion ties. The reflecting mesh is attached to the front net. The concept has been demonstrated by means of simple demonstrator hardware. A preliminary design o fa3m diameter, 10 GHz reflector with a focal length to diam- eter ratio F/D =0 .4 that could be packaged within an envelope of 0.1 × 0.2 × 0.8 m3 is presented.
... Other companies have used traditional technologies in novel designs. Four example designs include the Deployable Structures Lab (DSL) design study for QinetiQ (UK) (developed for micro satellites [2]), AEC-Able's Ultraflex Array (developed for micro satellites [3]), L'Garde's inflatable ITSAT array (developed for micro satellites [4]) and Aerospace Corporation's Powersphere (developed for micro/nano satellites [5]). The first three systems listed are aimed at micro satellites (i.e. ...
In recent years there have been many advances in the miniaturization of electronic and mechanical technologies for space applications. However, the satellite power requirement does not reduce linearly with the satellite mass, creating the need for small satellite deployable arrays. This paper outlines the current state of technology for small satellite deployable structures, briefly discussing the current and near future systems that have been made known to the international scientific community. A concept design outline of a nano satellite area deployment device is then presented. This design makes use of tape springs to drive the deployment of a solar array blanket in three dimensions. Further research in this area is then briefly outlined.
