Design and Optimization of a Shape Memory Alloy-Based Self-Folding Sheet

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Edwin Peraza-Hernandez ◽  
Darren Hartl ◽  
Edgar Galvan ◽  
Richard Malak
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Three Dimensional ◽  
Building Blocks ◽  
Passive Layer ◽  
Von Mises Stress ◽  
Maximum Temperature ◽  
Radius Of Curvature ◽  
Folding Angle ◽  
The Impact

Origami engineering—the practice of creating useful three-dimensional structures through folding and fold-like operations on two-dimensional building-blocks—has the potential to impact several areas of design and manufacturing. In this article, we study a new concept for a self-folding system. It consists of an active, self-morphing laminate that includes two meshes of thermally-actuated shape memory alloy (SMA) wire separated by a compliant passive layer. The goal of this article is to analyze the folding behavior and examine key engineering tradeoffs associated with the proposed system. We consider the impact of several design variables including mesh wire thickness, mesh wire spacing, thickness of the insulating elastomer layer, and heating power. Response parameters of interest include effective folding angle, maximum von Mises stress in the SMA, maximum temperature in the SMA, maximum temperature in the elastomer, and radius of curvature at the fold line. We identify an optimized physical realization for maximizing folding capability under mechanical and thermal failure constraints. Furthermore, we conclude that the proposed self-folding system is capable of achieving folds of significant magnitude (as measured by the effective folding angle) as required to create useful 3D structures.

Simulation-Based Design of a Self-Folding Smart Material System

2013 ◽  
Author(s):  
Edwin Peraza-Hernandez ◽  
Darren Hartl ◽  
Richard Malak
Keyword(s):  
Three Dimensional ◽  
Building Blocks ◽  
Passive Layer ◽  
Heating Power ◽  
Von Mises Stress ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Material System ◽  
Design Variables ◽  
Von Mises

Origami engineering — the practice of creating useful three-dimensional structures through folding operations on two-dimensional building-blocks — is receiving increased attention from the science, mathematics, and engineering communities. The topic of this paper is a new concept for a self-folding material system. It consists of an active, self-morphing laminate that includes two meshes of thermally-actuated shape memory alloy (SMA) separated by a compliant passive layer. The goal of this paper is to analyze several of the key engineering tradeoffs associated with the proposed self-folding material system. In particular, we examine how key design variables affect folding behavior in an SMA mesh-based folding sheet. The design parameters we consider in this study are wire thickness, mesh wire spacing, thickness of the insulating elastomer layer, and heating power. The output parameters are maximum von Mises stress in the SMA, maximum temperature in the SMA, and minimum folding angle. The results show that maximum temperature in the SMA is mostly dependent on the total heating power per unit width of SMA. The results also indicate that through-heating — heat transfer from one SMA layer to the other through the insulating elastomer — can impede folding for some physical configurations. However, we also find that one can mitigate this effect using a staggered mesh configuration in which the SMA wires on different layers are not aligned. Based on our results, we conclude that the new staggered mesh design can be effective in preventing unintended transformation of the non-actuated layer.

Computational Design of a Reconfigurable Origami Space Structure Incorporating Shape Memory Alloy Thin Films

2012 ◽  
Author(s):  
Darren Hartl ◽  
Kathryn Lane ◽  
Richard Malak
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Three Dimensional ◽  
Computational Design ◽  
Passive Layer ◽  
Space Structure ◽  
Material System ◽  
Transient Effects ◽  
Element Analysis ◽  
Shell Elements

The subject of origami design is garnering increased attention from the science, mathematics, and engineering communities. However, relatively little research exists on understanding the behavioral aspects of the material system undergoing the folding operations. This work considers the design and analysis of a novel concept for a self-folding structure. It consists of an active, self-morphing laminate that includes thermally actuated shape memory alloy (SMA) layers and a compliant passive layer. Multiple layers allow folds in both the positive and negative directions relative to the laminate normal. The layers are configured to allow continuously variable folding operations based only on which regions are heated. For the purposes of demonstration, an example problem is considered whereby a thin structure is designed that can be stored in a flat sheet configuration and then morph using sets of folds toward two distinct shapes. We examine the effects of fold width, layer thicknesses, and activation power history on the geometric configurations that can be obtained. The design efforts are supported by a comprehensive and accurate three-dimensional constitutive model for SMAs implemented into a finite element analysis (FEA) framework. Shell elements and laminate theory are used to increase the computational efficiency of the analysis. Discussion of the complex effects of active folding in an SMA laminate sheet with in-plane homogeneity, including transient effects, are discussed.

Shape memory alloy–actuated prestressed composites with application to morphing automotive fender skirts

2018 ◽  
Vol 30 (3) ◽  
pp. 479-494 ◽  
Author(s):  
Venkata Siva C Chillara ◽  
Leon M Headings ◽  
Ryohei Tsuruta ◽  
Eiji Itakura ◽  
Umesh Gandhi ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Design Procedure ◽  
Building Blocks ◽  
Smart Composite ◽  
Thermally Induced ◽  
One Dimensional ◽  
Flat Shape

This work presents smart laminated composites that enable morphing vehicle structures. Morphing panels can be effective for drag reduction, for example, adaptive fender skirts. Mechanical prestress provides tailored curvature in composites without the drawbacks of thermally induced residual stress. When driven by smart materials such as shape memory alloys, mechanically-prestressed composites can serve as building blocks for morphing structures. An analytical energy-based model is presented to calculate the curved shape of a composite as a function of force applied by an embedded actuator. Shape transition is modeled by providing the actuation force as an input to a one-dimensional thermomechanical constitutive model of a shape memory alloy wire. A design procedure, based on the analytical model, is presented for morphing fender skirts comprising radially configured smart composite elements. A half-scale fender skirt for a compact passenger car is designed, fabricated, and tested. The demonstrator has a domed unactuated shape and morphs to a flat shape when actuated using shape memory alloys. Rapid actuation is demonstrated by coupling shape memory alloys with integrated quick-release latches; the latches reduce actuation time by 95%. The demonstrator is 62% lighter than an equivalent dome-shaped steel fender skirt.

scholarly journals BESTest for Integrated Outdoor-Indoor Energy Balance Modelling

2021 ◽  
Author(s):  
Mohammed Bakkali ◽  
Yasunobu Ashie
Keyword(s):  
Energy Balance ◽  
Three Dimensional ◽  
Building Blocks ◽  
Building Energy ◽  
Energy Simulation ◽  
Balance Model ◽  
Fully Integrated ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact

In our growing cities, climate change and energy related uncertainties are of great concern. The impact of the Urban Heat Island on comfort, health and the way we use energy still requires further clarification. The outdoor-indoor energy balance model (3D-City Irradiance) presented in this article was developed so as to address these issues. The effects of view factors between urban surfaces on three-dimensional radiation and the effects of fully integrated outdoor-indoor energy balance schemes on heat islands and building indoor thermal loads could be included within different building blocks at a resolution of several metres. The model operated under the ‘stand alone’ mode. It was tested using the Building Energy Simulation Test (BESTest) which demonstrated good levels of agreement for diurnal and seasonal simulations.

scholarly journals An analytical model for crack monitoring of the shape memory alloy intelligent concrete

2019 ◽  
Vol 31 (1) ◽  
pp. 100-116 ◽  
Author(s):  
Bingfei Liu ◽  
Qingfei Wang ◽  
Kai Yin ◽  
Liwen Wang
Keyword(s):  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
One Dimensional ◽  
Monitoring Model ◽  
Crack Monitoring ◽  
The One

A theoretical model for the crack monitoring of the shape memory alloy intelligent concrete is presented in this work. The mechanical properties of shape memory alloy materials are first given by the experimental test. The one-dimensional constitutive model of the shape memory alloys is reviewed by degenerating from a three-dimensional model, and the behaviors of the shape memory alloys under different working conditions are then discussed. By combining the electrical resistivity model and the one-dimensional shape memory alloy constitutive model, the crack monitoring model of the shape memory alloy intelligent concrete is given, and the relationships between the crack width of the concrete and the electrical resistance variation of the shape memory alloy materials for different crack monitoring processes of shape memory alloy intelligent concrete are finally presented. The numerical results of the present model are compared with the published experimental data to verify the correctness of the model.

scholarly journals Modeling the behavior of bilayer shape memory alloy/functionally graded material beams considering asymmetric shape memory alloy response

2019 ◽  
Vol 31 (1) ◽  
pp. 84-99 ◽  
Author(s):  
Nguyen Van Viet ◽  
Wael Zaki ◽  
Rehan Umer ◽  
Quan Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Functionally Graded Material ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Alloy Layer ◽  
Functionally Graded ◽  
Tension And Compression ◽  
Graded Material ◽  
Asymmetric Shape

A new model is proposed to describe the response of laminated composite beams consisting of one shape memory alloy layer and one functionally graded material layer. The model accounts for asymmetry in tension and compression of the shape memory alloy behavior and successfully describes the dependence of the position of the neutral surface on phase transformation within the shape memory alloy and on the load direction. Moreover, the model is capable of describing the response of the composite beam to both loading and unloading cases. In particular, the derivation of the equations governing the behavior of the beam during unloading is presented for the first time. The effect of the functionally graded material gradient index and of temperature on the neutral axis deviation and on the overall behavior of the beam is also discussed. The results obtained using the model are shown to fit three-dimensional finite element simulations of the same beam.

Design of a Massively Reconfigurable Origami Space Structure Incorporating Shape Memory Alloys

2012 ◽  
Author(s):  
Darren Hartl ◽  
Kathryn Lane ◽  
Richard Malak
Keyword(s):  
Shape Memory ◽  
Three Dimensional ◽  
Passive Layer ◽  
Space Structure ◽  
Integration Scheme ◽  
Cylindrical Shape ◽  
Material System ◽  
Analysis Model ◽  
Element Analysis ◽  
Design Assessment

The subject of origami design has recently garnered increasing attention from the science, mathematics, and engineering communities. Mathematically rigorous frameworks have been developed that allow the identification of folding patterns needed to obtain a final three-dimensional goal shape. However, relatively little research exists on the problem of understanding the behavioral aspects of the material system undergoing the folding operations. This work considers the design and analysis of a novel concept for a self-folding material system. The system consists of an active, self-morphing laminate structure that includes thermally actuated shape memory alloy (SMA) layers and a compliant passive layer. Multiple layers allow folds in both directions (e.g., cross-folds). The layers are configured to allow continuously variable folding operations based only on which regions are heated. For the purposes of demonstration, an example problem is considered whereby an autonomous planetary landing craft is designed that can be stored in a flat sheet configuration, morph using a set of folds into a stable shape for safe descent through a gaseous atmosphere, and then, once landed, morph again toward a cylindrical shape for the purpose of rolling locomotion. We examine the effects of fold width, layer thicknesses, and activation parameters on the geometric configurations that can be obtained. The design efforts are supported by realistic morphing structural analysis tools. These include a comprehensive and accurate three-dimensional constitutive model for SMAs implemented into a finite element analysis (FEA) framework (the Abaqus Unified FEA suite) using a robust and efficient numerical integration scheme. Shell elements and laminate theory are used to increase the computational efficiency of the analysis. Model pre-processing, submission, and post-processing scripting methods are used to automate the design assessment tasks.

scholarly journals Ni-Ti Shape Memory Alloy Coatings for Structural Applications: Optimization of HVOF Spraying Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Carmen De Crescenzo ◽  
Despina Karatza ◽  
Dino Musmarra ◽  
Simeone Chianese ◽  
Theocharis Baxevanis ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Scale ◽  
Thermal Spray Technology ◽  
Spray Parameters ◽  
Hvof Spraying ◽  
Structural Applications ◽  
External Stimuli ◽  
Steel Substrates ◽  
The Impact

This work aims at contributing to the development of a revolutionary technology based on shape memory alloy (SMA) coatings deposited on-site to large-scale metallic structural elements, which operate in extreme environmental conditions, such as steel bridges and buildings. The proposed technology will contribute to improve the integrity of metallic civil structures, to alter and control their mechanical properties by external stimuli, to contribute to the stiffness and rigidity of an elastic metallic structure, to safely withstand the expected loading conditions, and to provide corrosion protection. To prove the feasibility of the concept, investigations were carried out by depositing commercial NiTinol Ni50.8Ti (at.%) powder, onto stainless steel substrates by using high-velocity oxygen-fuel thermal spray technology. While the NiTinol has been known since decades, this intermetallic alloy, as well as no other alloy, was ever used as the SMA-coating material. Due to the influence of dynamics of spraying and the impact energy of the powder particles on the properties of thermally sprayed coatings, the effects of the main spray parameters, namely, spray distance, fuel-to-oxygen feed rate ratio, and coating thickness, on the quality and properties of the coating, in terms of hardness, adhesion, roughness, and microstructure, were investigated.

Sign in / Sign up

Export Citation Format

Share Document