A Black Box Design Approach to Avian-Inspired SMA Coil Actuated Wearable Morphing Angel Wings

2017 ◽  
Author(s):  
Sean Dalton ◽  
Henry Koon ◽  
Jennifer O’Malley ◽  
Julianna Abel
Keyword(s):  
High Energy ◽  
Essential Elements ◽  
Black Box ◽  
Design Approach ◽  
High Energy Density ◽  
Parameter Study ◽  
University Of Minnesota ◽  
Theatre Arts ◽  
Closed Span ◽  
Actuator System

Black box design is a constraint driven design approach that distills essential elements of a physical process into inputs and outputs. This paper details the black box design implementation and validation of shape memory alloy (SMA) coil actuators as active members in a Watt I six bar avian-inspired wearable morphing angel wing mechanism. SMA coil actuators leverage the unique characteristics of high energy density SMA wire by providing a compact structural platform for large actuation displacement applications. The moderate force and displacement performance of low spring index coil actuators paired with their virtually silent actuation performance made them an attractive actuator solution to an avian-inspired wearable morphing wing mechanism for the University of Minnesota Department of Theatre Arts and Dance production of ‘Marisol’. The wing design constraints (extended span of 7.5 ft, a closed span of 3 ft) required a tailorable actuator system with capacity to perform at particular target force and strain metrics cyclically. A low spring index parameter study was conducted to facilitate an accelerated phase of design prototyping. The parameter study featured six SMA coil actuator prototypes made with 0.012” diameter Dynalloy Flexinol® wire of varying spring indexes (C = 2.5–4.9). The coil actuators were manufactured through a CNC winding process, shape set in a furnace at 450 °C for 10 minutes, and water quenched for hardening. A series of thermomechanical actuation tests were conducted to experimentally characterize the low spring index actuation performances. The coil actuation characterizations demonstrated increased force and decreased actuator displacement corresponding to decreased spring indexes. Scaling these results aided an accelerated design of an actuator system. The actuator system consisted of four C = 3.05 coil actuators wound with 0.02” diameter SMA that were integrated into each Watt I mechanism. The characterization of the force-displacement profiles for low index SMA coil actuators provides an effective empirical design strategy for scaling actuator performance to mechanical systems requiring moderate force, moderate displacement actuators.

A Design Method for Shape Memory Alloy Actuators Accounting for Cyclic Shakedown With Constrained Allowable Strain

2010 ◽  
Author(s):  
WonHee Kim ◽  
Brian M. Barnes ◽  
Jonathan E. Luntz ◽  
Diann E. Brei
Keyword(s):  
Design Method ◽  
Mechanical Strain ◽  
High Energy ◽  
Design Guidelines ◽  
Design Approach ◽  
High Energy Density ◽  
Interface Position ◽  
Design Variables ◽  
Graphical Design ◽  
Actuation Strain

The high energy density actuation potential of SMA wire is tempered by conservative design guidelines set to mitigate complex factors such as functional fatigue (shakedown). Shakedown causes problems of stroke loss and interface position drift between the system and the SMA wire under higher stress levels if the wire does not undergo a pre-installation shakedown procedure. Limiting actuation strain has been reported as reducing shakedown as well as increasing fatigue life. One approach to limit actuation strain is using a mechanical strain limiter which sets a fixed Martensite strain position — useful for the development of in-device shakedown procedures which eliminates time consuming pre-installation shakedown procedures. This paper presents a new graphical design approach for SMA wire actuators which accounts for shakedown with the use of mechanical strain limiters to enable higher stress designs to maximize actuator performance. Experimental data on the effect of strain limiters along with stroke and work density contours form the basis for the new graphical design method. For each independent mechanical strain limiter, the maximum of the individual post-shakedown austenite curves at a range of applied stress are combined into a conglomerate stabilization design curve. These curves over a set of mechanical strain limiters provide steady state performance prediction for SMA actuation, effectively decoupling the shakedown material performance from design variables that affect the shakedown. The use and benefits of this new design approach are demonstrated with a common constant force actuator design example. This new design approach, which accounts for shakedown, supports design of SMA actuators at higher stresses with more economical use of material/power, and enables the utilization of strain limiters for cost saving in-device shakedown procedures.

scholarly journals Optimization of Phase-Change Material–Elastomer Composite and Integration in Kirigami-Inspired Voxel-Based Actuators

2021 ◽  
Vol 8 ◽  
Author(s):  
Gilles Decroly ◽  
Romain Raffoul ◽  
Clara Deslypere ◽  
Paul Leroy ◽  
Louis Van Hove ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Close Contact ◽  
Low Cost ◽  
High Energy ◽  
Design Approach ◽  
High Energy Density ◽  
Complex Tasks ◽  
Change Material ◽  
Actuation Strain

Phase-change material–elastomer composite (PCMEC) actuators are composed of a soft elastomer matrix embedding a phase-change fluid, typically ethanol, in microbubbles. When increasing the temperature, the phase change in each bubble induces a macroscopic expansion of the matrix. This class of actuators is promising for soft robotic applications because of their high energy density and actuation strain, and their low cost and easy manufacturing. However, several limitations must be addressed, such as the high actuation temperature and slow actuation speed. Moreover, the lack of a consistent design approach limits the possibility to build PCMEC-based soft robots able to achieve complex tasks. In this work, a new approach to manufacture PCMEC actuators with different fluid–elastomer combinations without altering the quality of the samples is proposed. The influence of the phase-change fluid and the elastomer on free elongation and bending is investigated. We demonstrate that choosing an appropriate fluid increases the actuation strain and speed, and decreases the actuation temperature compared with ethanol, allowing PCMECs to be used in close contact with the human body. Similarly, by using different elastomer materials, the actuator stiffness can be modified, and the experimental results showed that the curvature is roughly proportional to the inverse of Young’s modulus of the pure matrix. To demonstrate the potential of the optimized PCMECs, a kirigami-inspired voxel-based design approach is proposed. PCMEC cubes are molded and reinforced externally by paper. Cuts in the paper induce anisotropy into the structure. Elementary voxels deforming according to the basic kinematics (bending, torsion, elongation, compression and shear) are presented. The combination of these voxels into modular and reconfigurable structures could open new possibilities towards the design of flexible robots able to perform complex tasks.

A rational co-design approach to the creation of new dielectric polymers with high energy density

2017 ◽  
Vol 24 (2) ◽  
pp. 732-743 ◽  
Author(s):  
Gregory M. Treich ◽  
Mattewos Tefferi ◽  
Shamima Nasreen ◽  
Arun Mannodi-Kanakkithodi ◽  
Zongze Li ◽  
...  
Keyword(s):  
Energy Density ◽  
High Energy ◽  
Design Approach ◽  
High Energy Density ◽  
The Creation

scholarly journals Target heating in high-energy-density matter experiments at the proposed GSI FAIR facility: Non-linear bunch rotation in SIS100 and optimization of spot size and pulse length

2004 ◽  
Vol 22 (4) ◽  
pp. 485-493 ◽  
Author(s):  
N.A. TAHIR ◽  
S. UDREA ◽  
C. DEUTSCH ◽  
V.E. FORTOV ◽  
N. GRANDJOUAN ◽  
...  
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Ion Beam ◽  
Pulse Length ◽  
Spot Size ◽  
High Energy ◽  
Particle Energy ◽  
High Energy Density ◽  
Parameter Study ◽  
Worst Case

The Gesellschaft für Schwerionenforschung (GSI) Darmstadt has been approved to build a new powerful facility named FAIR (Facility for Antiprotons and Ion Research) which involves the construction of a new synchrotron ring SIS100. In this paper, we will report on the results of a parameter study that has been carried out to estimate the minimum pulse lengths and the maximum peak powers achievable, using bunch rotation RF gymnastic-including nonlinearities of the RF gap voltage in SIS100, using a longitudinal dynamics particle in cell (PIC) code, ESME. These calculations have shown that a pulse length of the order of 20 ns may be possible when no prebunching is performed while the pulse length gradually increases with the prebunching voltage. Three different cases, including 0.4 GeV/u, 1 GeV/u, and 2.7 GeV/u are considered for the particle energy. The worst case is for the kinetic energy of 0.4 GeV/u which leads to a pulse length of about 100 ns for a prebunching voltage of 100 kV (RF amplitude). The peak power was found to have a maximum, however, at 0.5–1.5kV prebunching voltage, depending on the mean kinetic energy of the ions. It is expected that the SIS100 will deliver a beam with an intensity of 1–2 × 1012 ions. Availability of such a powerful beam will make it possible to study the properties of high-energy-density (HED) matter in a parameter range that is very difficult to access by other means. These studies involve irradiation of high density targets by the ion beam for which optimization of the target heating is the key problem. The temperature to which a target can be heated depends on the power that is deposited in the material by the projectile ions. The optimization of the power, however, depends on the interplay of various parameters including beam intensity, beam spot area, and duration of the ion bunch. The purpose of this paper is to determine a set of the above parameters that would lead to an optimized target heating by the future SIS100 beam.

scholarly journals Biochar Characterization Produced from Walnut Shell Biomass through Slow Pyrolysis: Sustainable for Soil Amendment and an Alternate Bio-Fuel

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Rami Alfattani ◽  
Mudasir Akbar Shah ◽  
Md Irfanul Haque Siddiqui ◽  
Masood Ashraf Ali ◽  
Ibrahim A. Alnaser
Keyword(s):  
Surface Area ◽  
Functional Characterization ◽  
Xrd Analysis ◽  
Thermal Conversion ◽  
High Energy ◽  
Essential Elements ◽  
High Energy Density ◽  
Walnut Shell ◽  
Slow Pyrolysis ◽  
Crystalline Nature

Bio-char has the ability to isolate carbon in soils and concurrently improve plant growth and soil quality, high energy density and also it can be used as an adsorbent for water treatment. In the current work, the characteristics of four different types of bio-chars, obtained from slow pyrolysis at 375 °C, produced from hard-, medium-, thin- and paper-shelled walnut residues have been studied. Bio-char properties such as proximate, ultimate analysis, heating values, surface area, pH values, thermal degradation behavior, morphological and crystalline nature and functional characterization using FTIR were determined. The pyrolytic behavior of bio-char is studied using thermogravimetric analysis (TGA) in an oxidizing atmosphere. SEM analysis confirmed morphological change and showed heterogeneous and rough texture structure. Crystalline nature of the bio-chars is established by X-ray powder diffraction (XRD) analysis. The maximum higher heating values (HHV), high fixed carbon content and surface area obtained for walnut shells (WS) samples are found as ~ 18.4 MJ kg−1, >80% and 58 m2/g, respectively. Improvement in HHV and decrease of O/C and H/C ratios lead the bio-char samples to fall into the category of coal and confirmed their hydrophobic, carbonized and aromatized nature. From the Fourier transform infra-red spectroscopy (FTIR), it is observed that there is alteration in functional groups with increase in temperature, and illustrated higher aromaticity. This showed that bio-chars have high potential to be used as solid fuel either for direct combustion or for thermal conversion processes in boilers, kilns and furnace. Further, from surface area and pH analysis of bio-chars, it is found that WS bio-chars have similar characteristics of adsorbents used for water purifications, retention of essential elements in soil and carbon sequestration.

Pilot-scale combustion studies with kraft lignin in a powder burner and a CFB boiler

TAPPI Journal ◽  
2010 ◽  
Vol 9 (6) ◽  
pp. 24-30 ◽  
Author(s):  
NIKLAS BERGLIN ◽  
PER TOMANI ◽  
HASSAN SALMAN ◽  
SOLVIE HERSTAD SVÄRD ◽  
LARS-ERIK ÅMAND
Keyword(s):  
Circulating Fluidized Bed ◽  
Black Liquor ◽  
Chloride Content ◽  
Pilot Scale ◽  
High Energy ◽  
Kraft Lignin ◽  
High Energy Density ◽  
Alkali Chloride ◽  
Cfb Boiler ◽  
Solid Biofuel

Processes have been developed to produce a solid biofuel with high energy density and low ash content from kraft lignin precipitated from black liquor. Pilot-scale tests of the lignin biofuel were carried out with a 150 kW powder burner and a 12 MW circulating fluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the air flows to reduce swirl. Lignin dried to 10% moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than did wood/bark powder. In the CFB boiler, lignin was easily handled and cofired together with bark. Although the filter cake was broken into smaller pieces and fines, the combustion was not disturbed. When cofiring lignin with bark, the sulfur emission increased compared with bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture also occurred with addition of limestone to the bed. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk.

A HIGH ENERGY DENSITY ZINC/OXYGEN BATTERY SYSTEM

1966 ◽  
Author(s):  
S. CHODOSH ◽  
E. KATSOULIS ◽  
M. ROSANSKY
Keyword(s):  
Energy Density ◽  
High Energy ◽  
High Energy Density ◽  
Battery System

Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery

2019 ◽  
Author(s):  
Zhao-Yang Zhang ◽  
Tao LI
Keyword(s):  
Energy Density ◽  
Solar Energy ◽  
High Performance ◽  
High Energy ◽  
Solar Thermal ◽  
High Energy Density ◽  
Low Grade ◽  
Thermal Battery ◽  
Low Grade Heat

Solar energy and ambient heat are two inexhaustible energy sources for addressing the global challenge of energy and sustainability. Solar thermal battery based on molecular switches that can store solar energy and release it as heat has recently attracted great interest, but its development is severely limited by both low energy density and short storage stability. On the other hand, the efficient recovery and upgrading of low-grade heat, especially that of the ambient heat, has been a great challenge. Here we report that solar energy and ambient heat can be simultaneously harvested and stored, which is enabled by room-temperature photochemical crystal-to-liquid transitions of small-molecule photoswitches. The two forms of energy are released together to produce high-temperature heat during the reverse photochemical phase change. This strategy, combined with molecular design, provides high energy density of 320-370 J/g and long-term storage stability (half-life of about 3 months). On this basis, we fabricate high-performance, flexible film devices of solar thermal battery, which can be readily recharged at room temperature with good cycling ability, show fast rate of heat release, and produce high-temperature heat that is >20<sup> o</sup>C higher than the ambient temperature. Our work opens up a new avenue to harvest ambient heat, and demonstrate a feasible strategy to develop high-performance solar thermal battery.

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