scholarly journals Shape Memory Activated Self-Deployable Solar Sails: Small-Scale Prototypes Manufacturing and Planarity Analysis by 3D Laser Scanner

Actuators ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 38 ◽  
Author(s):  
Alberto Boschetto ◽  
Luana Bottini ◽  
Girolamo Costanza ◽  
Maria Elisa Tata
Keyword(s):  
Shape Memory ◽  
Laser Scanner ◽  
Solar Sail ◽  
Small Scale ◽  
Propulsive Force ◽  
Momentum Exchange ◽  
Solar Sails ◽  
Level Curves ◽  
Wolfram Mathematica ◽  
Critical Zones

Solar sails are propellantless systems where the propulsive force is given by the momentum exchange of reflecting photons. Thanks to the use of shape memory alloys for the self-actuation of the system, complexity of the structure itself has decreased and so has the weight of the whole structure. Four self-deploying systems based on the NiTi shape memory wires have been designed and manufactured in different configurations (wires disposal and folding number). The deployed solar sails surfaces have been acquired by a Nextengine 3D Laser Scanner based on the Multistripe Triangulation. 3D maps have been pre-processed through Geomagic Studio and then elaborated in the Wolfram Mathematica environment. The planarity degree has been evaluated as level curves from the regression plane highlighting marked differences between the four configurations and locating the vertices as the most critical zones. These results are useful in the optimization of the best folding solution both in the weight/surface reduction and in the planarity degree of the solar sail.

scholarly journals Design and Characterization of a Small-Scale Solar Sail Prototype by Integrating NiTi SMA and Carbon Fibre Composite

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Girolamo Costanza ◽  
Gabriele Leoncini ◽  
Fabrizio Quadrini ◽  
Maria Elisa Tata
Keyword(s):  
Carbon Fibre ◽  
Shape Memory ◽  
Fibre Composite ◽  
Weight Ratio ◽  
Solar Sail ◽  
Structure Design ◽  
Small Scale ◽  
Momentum Exchange ◽  
Carbon Fibre Composite ◽  
Solar Sails

Solar sails are propellantless systems where the propulsive force is given by the momentum exchange of reflecting photons. In this study, a self-deploying system based on NiTi shape memory wires and sheets has been designed and manufactured. A small-scale prototype of solar sail with carbon fibre loom has been developed. Different configurations have been tested to optimize material and structure design of the small-scale solar sail. In particular the attention has been focused on the surface/weight ratio and the deployment of the solar sail. By reducing weight and enlarging the surface, it is possible to obtain high values of characteristic acceleration that is one of the main parameters for a successful use of the solar sail as propulsion system. Thanks to the use of shape memory alloys for self-actuation of the system, complexity of the structure itself decreases. Moreover, sail deployment is simpler.

scholarly journals A Novel Self-Deployable Solar Sail System Activated by Shape Memory Alloys

Aerospace ◽  
2019 ◽  
Vol 6 (7) ◽  
pp. 78 ◽  
Author(s):  
Gianluigi Bovesecchi ◽  
Sandra Corasaniti ◽  
Girolamo Costanza ◽  
Maria Elisa Tata
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Environmental Conditions ◽  
Solar Sail ◽  
Operating Conditions ◽  
Small Scale ◽  
Space Vehicles ◽  
Solar Sails ◽  
Suitable Material ◽  
Transfer Mechanisms

This work deals with the feasibility and reliability about the use of shape memory alloys (SMAs) as mechanical actuators for solar sail self-deployment instead of heavy and bulky mechanical booms. Solar sails exploit radiation pressure a as propulsion system for the exploration of the solar system. Sunlight is used to propel space vehicles by reflecting solar photons from a large and light-weight material, so that no propellant is required for primary propulsion. In this work, different small-scale solar sail prototypes (SSP) were studied, manufactured, and tested for bending and in three different environmental conditions to simulate as much as possible the real operating conditions where the solar sails work. Kapton is the most suitable material for sail production and, in the space missions till now, activated booms as deployment systems have always been used. In the present work for the activation of the SMA elements some visible lamps have been employed to simulate the solar radiation and time-temperature diagrams have been acquired for different sail geometries and environmental conditions. Heat transfer mechanisms have been discussed and the minimum distance from the sun allowing the full self-deployment of the sail have also been calculated.

A novel methodology for solar sail opening employing shape memory alloy elements

2018 ◽  
Vol 29 (9) ◽  
pp. 1793-1798 ◽  
Author(s):  
Girolamo Costanza ◽  
Maria Elisa Tata
Keyword(s):  
Shape Memory ◽  
Atmospheric Condition ◽  
Low Pressure ◽  
Small Scale ◽  
Space Vehicles ◽  
Halogen Lamp ◽  
Solar Sails ◽  
Suitable Material ◽  
Activation Times ◽  
Al Coating

Solar sails exploit the radiation pressure as propulsion system. Sunlight is used to propel space vehicles by reflecting solar photons from a large and lightweight material, so that no propellant is required for primary propulsion. Kapton seems to be the most suitable material for the sail production and in the space missions till now activated booms as deployment systems have always been used. In this work, an innovative self-deploying system based on NiTi shape memory wires has been designed and manufactured in a small-scale prototype. As kapton has always been employed with a thin Al coating on the surface of the sail, commercial pure Al thin sheets with thin adhesive kapton have been used in order to simulate the sail. The attention has been focused, in the deployment experiments performed in the laboratory, on the effect of different heating methods and different pressure conditions on the activation times. The folded configuration chosen has been deployed in atmospheric condition and in low pressure condition (0.05 bar) inside a oven connected to a rotary pump. For what concerns the heating methods, the attention has been focused on low-pressure oven ISCO NSV 9035 (1.3 kW) and on halogen lamp (1 kW) in order to obtain the self-deployment of the sail. Some comparisons between the two configurations in the different environmental conditions have been performed. In all cases, the full self-activation of the sail has been achieved.

scholarly journals Assessment of Stem Volume on Plots Using Terrestrial Laser Scanner: A Precision Forestry Application

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 301
Author(s):  
Dimitrios Panagiotidis ◽  
Azadeh Abdollahnejad ◽  
Martin Slavík
Keyword(s):  
Norway Spruce ◽  
Laser Scanner ◽  
Estimation Methods ◽  
Coefficient Of Determination ◽  
Stem Volume ◽  
Small Scale ◽  
Terrestrial Laser Scanner ◽  
Precision Forestry ◽  
Total Tree ◽  
European Oak

Timber volume is an important asset, not only as an ecological component, but also as a key source of present and future revenues, which requires precise estimates. We used the Trimble TX8 survey-grade terrestrial laser scanner (TLS) to create a detailed 3D point cloud for extracting total tree height and diameter at breast height (1.3 m; DBH). We compared two different methods to accurately estimate total tree heights: the first method was based on a modified version of the local maxima algorithm for treetop detection, “HTTD”, and for the second method we used the centers of stem cross-sections at stump height (30 cm), “HTSP”. DBH was estimated by a computationally robust algebraic circle-fitting algorithm through hierarchical cluster analysis (HCA). This study aimed to assess the accuracy of these descriptors for evaluating total stem volume by comparing the results with the reference tree measurements. The difference between the estimated total stem volume from HTTD and measured stems was 2.732 m3 for European oak and 2.971 m3 for Norway spruce; differences between the estimated volume from HTSP and measured stems was 1.228 m3 and 2.006 m3 for European oak and Norway spruce, respectively. The coefficient of determination indicated a strong relationship between the measured and estimated total stem volumes from both height estimation methods with an R2 = 0.89 for HTTD and R2 = 0.87 for HTSP for European oak, and R2 = 0.98 for both HTTD and HTSP for Norway spruce. Our study has demonstrated the feasibility of finer-resolution remote sensing data for semi-automatic stem volumetric modeling of small-scale studies with high accuracy as a potential advancement in precision forestry.

Conceptual Design of an Experiment for the International Space Station About Shape Memory Composite in Space Environment

2017 ◽  
Author(s):  
Loredana Santo ◽  
Denise Bellisario ◽  
Giovanni Matteo Tedde ◽  
Fabrizio Quadrini
Keyword(s):  
Shape Memory ◽  
International Space Station ◽  
Space Station ◽  
Sun Exposure ◽  
Aging Effect ◽  
Space Environment ◽  
Aging Effects ◽  
Solar Sails ◽  
International Space ◽  
Shape Memory Composite

Shape memory polymers (SMP) and composites (SMPC) may be used for many applications in Space, from self-deployable structures (such as solar sails, panels, shields, booms and antennas), to grabbing systems for Space debris removal, up to new-concept actuators for telescope mirror tuning. Experiments on the International Space Station are necessary for testing prototypes in relevant environment, above all for the absence of gravity which affects deployment of slender structures but also to evaluate the aging effects of the Space environment. In fact, several aging mechanisms are possible, from polymer cracking to cross-linking and erosion, and different behaviors are expected as well, from consolidating the temporary shape to composite degradation. Evaluating the possibility of shape recovery because of sun exposure is another interesting point. In this study, a possible experiment on the ISS is shown with the aim of evaluating the aging effect of Space on material performances. The sample structure is described as well as the testing strategy.

Micro pulling down growth of very thin shape memory alloys single crystals

2017 ◽  
Vol 10 (01) ◽  
pp. 1740003 ◽  
Author(s):  
I. López-Ferreño ◽  
J. San Juan ◽  
T. Breczewski ◽  
G. A. López ◽  
M. L. Nó
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Single Crystals ◽  
Functional Materials ◽  
Small Scale ◽  
Cylindrical Shape ◽  
Minimum Diameter ◽  
Wide Range

Shape memory alloys (SMAs) have attracted much attention in the last decades due to their thermo-mechanical properties such as superelasticity and shape memory effect. Among the different families of SMAs, Cu–Al–Ni alloys exhibit these properties in a wide range of temperatures including the temperature range of 100–200[Formula: see text]C, where there is a technological demand of these functional materials, and exhibit excellent behavior at small scale making them more competitive for applications in Micro Electro-Mechanical Systems (MEMS). However, polycrystalline alloys of Cu-based SMAs are very brittle so that they show their best thermo-mechanical properties in single-crystal state. Nowadays, conventional Bridgman and Czochralski methods are being applied to elaborate single-crystal rods up to a minimum diameter of 1[Formula: see text]mm, but no works have been reported for smaller diameters. With the aim of synthesizing very thin single-crystals, the Micro-Pulling Down ([Formula: see text]-PD) technique has been applied, for which the capillarity and surface tension between crucible and the melt play a critical role. The [Formula: see text]-PD method has been successfully applied to elaborate several cylindrical shape thin single-crystals down to 200[Formula: see text][Formula: see text]m in diameter. Finally, the martensitic transformation, which is responsible for the shape memory properties of these alloys, has been characterized for different single-crystals. The experimental results evidence the good quality of the grown single-crystals.

Design of a Compliant Industrial Gripper Driven by a Bistable Shape Memory Alloy Actuator

2020 ◽  
Author(s):  
Dominik Scholtes ◽  
Stefan Seelecke ◽  
Gianluca Rizzello ◽  
Paul Motzki
Keyword(s):  
Shape Memory ◽  
High Energy ◽  
Industrial Applications ◽  
High Energy Density ◽  
Small Scale ◽  
Monitoring And Control ◽  
Actuation System ◽  
First Results ◽  
Functional Prototype ◽  
And Control

Abstract Within industrial manufacturing most processing steps are accompanied by transporting and positioning of workpieces. The active interfaces between handling system and workpiece are industrial grippers, which often are driven by pneumatics, especially in small scale areas. On the way to higher energy efficiency and digital factories, companies are looking for new actuation technologies with more sensor integration and better efficiencies. Commonly used actuators like solenoids and electric engines are in many cases too heavy and large for direct integration into the gripping system. Due to their high energy density shape memory alloys (SMA) are suited to overcome those drawbacks of conventional actuators. Additionally, they feature self-sensing abilities that lead to sensor-less monitoring and control of the actuation system. Another drawback of conventional grippers is their design, which is based on moving parts with linear guides and bearings. These parts are prone to wear, especially in abrasive environments. This can be overcome by a compliant gripper design that is based on flexure hinges and thus dispenses with joints, bearings and guides. In the presented work, the development process of a functional prototype for a compliant gripper driven by a bistable SMA actuation unit for industrial applications is outlined. The focus lies on the development of the SMA actuator, while the first design approach for the compliant gripper mechanism with solid state joints is proposed. The result is a working gripper-prototype which is mainly made of 3D-printed parts. First results of validation experiments are discussed.

Small-scale Experiments and Simulations of Centrifugal Membrane Deployment of Solar Sail Craft 'IKAROS'

2011 ◽  
Author(s):  
Nobukatsu Okuizumi ◽  
Azusa Muta ◽  
Saburo Matsunaga ◽  
Hiraku Sakamoto ◽  
Yoji Shirasawa ◽  
...  
Keyword(s):  
Solar Sail ◽  
Small Scale

Microphysics of the air-sea coupling at high winds and its role in the dynamics and thermodynamics of severe sea storms

2020 ◽  
Author(s):  
Yuliya Troitskaya ◽  
Alexander Kandaurov ◽  
Daniil Sergeev ◽  
Olga Ermakova ◽  
Dmitrii Kozlov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Water Surface ◽  
Synergetic Effect ◽  
Ocean Surface ◽  
Small Scale ◽  
Momentum Exchange ◽  
Momentum Fluxes ◽  
The Impact ◽  
High Winds

<p>Showing the record strengths and growth-rates, a number of recent hurricanes have highlighted needs for improving forecasts of tropical cyclone intensities most sensitive to models of the air-sea coupling. Especially challenging is the nature and effect of the very small-scale phenomena, the sea-spray and foam, supposed to strongly affecting the momentum- and heat- air-sea fluxes at strong winds. This talk will focus on our progress in understanding and describing these "micro-scale" processes, their physical properties, the spray and foam mediated air-sea fluxes and the impact on the development of marine storms.</p><p>The starting points for this study were two laboratory experiments. The first one was designed for investigation of the spray generation mechanisms at high winds. We found out 3 dominant spray generating mechanisms: stretching liquid ligaments, bursting bubbles, splashing of the falling droplets and "bag-breakup". We investigated the efficiency spray-production mechanisms and developed the empirical statistics of the numbers of the spray generating events of each type. Basing on the "white-cap method" we found out the dependence of the spray-generating events on the wind fetch. The main attention was paid to the "bag-breakup" mechanism. Here we studied in detail the statistics of spray produced from one "bag-breakup" event. Basing on these developments, we estimated heat and momentum fluxes from the spray-generating events of different types and found out the dominant role of the "bag-breakup" mechanism.</p><p>To estimate the direct heat and momentum fluxes from the ocean surface to the atmosphere, we studied in the special experiment the foam impact on the short-wave part of the surface waves and the heat momentum exchange in the atmospheric boundary layer at high winds. Based on these results, we suggest a simple model for the aerodynamic and temperature roughness and the eddy viscosity in the turbulent boundary layer over a fractionally foam-covered water surface.</p><p>The synergetic effect of foam at the water surface and spray in the marine atmospheric boundary layer on ocean surface resistance at high winds is estimated so as to be able to explain the observed peculiarities of the air-sea fluxes at stormy conditions. Calculations within the nonhydrostatic axisymmetric model show, that the "microphysics" of the air-sea coupling significantly accelerate development of the ocean storm.</p><p>This work was supported by RFBR grant 19-05-00249 and RSF grant 19-17-00209.</p>

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