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.

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.

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.

Analytical model for a superelastic Timoshenko shape memory alloy beam subjected to a loading–unloading cycle

2018 ◽  
Vol 29 (20) ◽  
pp. 3902-3922 ◽  
Author(s):  
Nguyen Van Viet ◽  
Wael Zaki ◽  
Rehan Umer
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Analytical Model ◽  
Solid Phase ◽  
Three Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

We propose a new analytical model for a superelastic shape memory alloy prismatic cantilever beam subjected to a concentrated force at the tip. The force is gradually increased and then removed and the corresponding distribution of phase transformation fields in the beam is determined, analytically, in both the transverse and longitudinal directions. Analytical moment–curvature and shear force–shear strain relations are also derived during loading and unloading of the beam. The proposed model is validated against an exact numerical beam model as well as a three-dimensional finite element analysis model for the same beam, with very good agreement in each case. Moreover, an experiment is proposed and carried out to characterize the load–deflection response of a shape memory alloy beam under the same boundary conditions as those considered in deriving the model. The obtained response is in good agreement with the analytical model as well as three-dimensional finite element analysis simulations. The analytical method provides a direct mathematical way for describing the material and structural properties of the beam and the distribution of the different solid phase regions as they change under the influence of an applied load and allows the determination of details such as the boundaries of solid phase regions immediately and accurately using equations. The same would require postprocessing at possibly significant computational cost and personal effort if finite element analysis or similar numerical methods are used.

Comparison of Three-Dimensional Shape Memory Alloy Constitutive Models: Finite Element Analysis of Actuation and Superelastic Responses of a Shape Memory Alloy Tube

2013 ◽  
Author(s):  
Pingping Zhu ◽  
L. Catherine Brinson ◽  
Edwin Peraza-Hernandez ◽  
Darren Hartl ◽  
Aaron Stebner
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Benchmark Problems ◽  
Internal Variables ◽  
Computationally Efficient ◽  
Element Analysis ◽  
Analysis And Design

Many three-dimensional constitutive models have been proposed to enhance the analysis and design of shape memory alloy (SMA) structural components. Phenomenological models are desirable for this purpose since they describe macroscopic responses using internal variables to govern the homogenized material response. Because they are computationally efficient on the scale of millimeters to meters, these models are often the only viable option when assessing the response of full-scale SMA components for engineering applications. Thus, many different 3D SMA constitutive models have been developed. However, for their intended user, the application engineer, a clear and straightforward methodology has not been established for selecting a model to use in a design process. A primary goal of the Consortium for the Advancement of Shape Memory Alloy Research and Technology (CASMART) modeling working group has been establishment of model selection methodology. One critical step in this process is the development of benchmark problems that clearly illustrate the capabilities and efficiencies of models. In this paper, we propose a set of benchmark problems centered on an SMA tube component. These problems have been selected to demonstrate both uniaxial and multiaxial, actuation and superelastic capabilities of 3D SMA models. We then use finite element simulations of these benchmark problems to compare and contrast both the material modeling and implementation of three unique SMA constitutive models.

A Computational Design Method for a Shape Memory Alloy Wire Actuated Compliant Finger

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Chao-Chieh Lan ◽  
You-Nien Yang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Design Method ◽  
Three Dimensional ◽  
Computational Design ◽  
Computational Method ◽  
Output Force ◽  
Robotic Manipulations ◽  
Experimental Validations ◽  
High Work

This paper presents a computational method to design a compliant finger for robotic manipulations. As traditional mechanical fingers require bulky electromagnetic motors and numerous relative moving parts to achieve dexterous motion, we propose a class of fingers; the manipulation of which relies on finger deflections. These compliant fingers are actuated by shape memory alloy (SMA) wires that exhibit high work-density, frictionless, and quiet operations. The combination of compliant members with embedded SMA wires makes the finger more compact and lightweight. Various SMA wire layouts are investigated to reduce their response time while maintaining sufficient output force. The mathematical models of finger deflection caused by SMA contraction are then derived along with experimental validations. As finger shapes are essential to the range of deflected motion and output force, we find its optimal initial shapes through the use of a shape parametrization technique. We further illustrate our method by designing a humanoid finger that is capable of three-dimensional manipulation. Since compliant fingers can be fabricated monolithically, we expect the proposed design method to be utilized for applications of various scales.

Analysis of Shape Memory Alloy Components Using Beam, Shell, and Continuum Finite Elements

2010 ◽  
Author(s):  
Darren Hartl ◽  
Tyler Zimmerman ◽  
Matthew Dilligan ◽  
James Mabe ◽  
Frederick Calkins
Keyword(s):  
Finite Elements ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Analysis Tool ◽  
Three Dimensional Model ◽  
Restoring Force ◽  
Element Analysis

This work discusses the increased capabilities of a three-dimensional analysis tool for shape memory alloy engineering components. As the number and complexity of proposed SMA applications increases, engineers and designers must seek out or develop more capable predictive methods. Three-dimensional models implemented in a continuum finite element analysis (FEA) framework can be applied to most SMA component geometries. However, such methods may require fine meshes in 3-D space, resulting in many degrees of freedom and potentially long analysis times. On the other hand, constitutive models implemented in one dimension can be simple and fast, but are restricted to a limited class of problems for which such reductions are appropriate (e.g., rods and beams). More recently, engineers have begun investigating more complex SMA bending components for which 2-D shell elements might provide a computationally efficient FEA discretization. Here we consider a single modeling tool (a material subroutine) that combines 1-D, 2-D, and 3-D implementations for use in a general FEA framework. As an example analysis case, we consider an SMA bending element that has been adhesively bonded to a carbon fiber-reinforced polymer (CFRP) laminate and is subjected to thermally-induced actuation. The active SMA and passive composite components are bonded in a pre-stressed configuration such that the elastic laminate provides a variable restoring force to the SMA during transformation, resulting in repeatable actuation cycles. This two-part bonded configuration is analyzed using different types of finite elements (1-D beam, 2-D shell, and full 3-D continuum elements). The constitutive behavior of the shape memory alloy is defined using an established three-dimensional model based on continuum thermodynamics and motivated by the methods of classical plasticity. A user material subroutine (UMAT) in an Abaqus Unified FEA framework is used to implement the model. The methodology for capturing 1-D, 2-D, and 3-D thermomechanical response in a single such UMAT is described. The run times of the various analyses are compared, and the relative accuracies of the results are discussed.

Finite Element Analysis of Creep and Thermal Stress for Shape Memory Alloy Joint

2010 ◽  
Vol 452-453 ◽  
pp. 537-540 ◽  
Author(s):  
Xue Feng Zhou ◽  
You Hai Zhi ◽  
Bing Wang Gou
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Thermal Strain ◽  
Three Dimensional ◽  
Transient State ◽  
Element Model ◽  
Element Analysis ◽  
Joint System ◽  
Radial Temperature

The three-dimensional (3D) finite element model of shape memory alloy (SMA) joint system under a clamped-clamped support was established. Using the coupled thermal-mechanical transient state analysis, stress distributions of models under the different loads (internal pressure, temperature) were investigated. And the temperature field, thermal strain field, stress and creep of the joint system were obtained. The results show, 1) for the non-coat SMA joint system, the interface in middle region of the joint’s internal wall is the dangerous region. In this region, the joint’s adhesion failures easily occur and the crack easily initiate. The joint’s coat can improve the fatigue life of joint system. 2) There are higher levels of radial temperature gradient, temperature strain and temperature stress between the internal and external walls of the joint. The creep strain in the internal-external walls of the joint is the main reason for adhesion failure in middle interfaces between the joint and the pipe.

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