Magneto-Active Elastomers
Multi-Field Responsive Origami Structures Faculty: Mary Frecker, Zoubeida Ounaies, Tim Simpson, Paris von Lockette, Jyh-Ming Lien, Rebecca Strzelec
Pennsylvania State University &
George Mason University
Micro-Scale Meso-Scale Macro-Scale
Project Overview
The EFRI-ODISSEI project aims to develop multi-field actuated origami structures that achieve folding and unfolding from a flat state to a complex, artistically inspired, 3D geometry. This work encompasses a multi-scale approach, ranging from frameworks based on material microstructure to the macroscopic 3D analysis of foldable structures. Each length scale contributes to the goal of this project by providing essential information only available at that level.
At the micro-scale, the effects of microstructure on the coupling properties of active materials are determined. For example, the squareness ratio of MAEs (saturation magnetization over remanent magnetization) is found to be dependent on volume concentration of barium hexaferrite.
Modeling Bending/Folding
25.0MV/m 37.5MV/m 62.5MV/m 56.2MV/m
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M
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H
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(a) (b)
Electro-Active Polymers
The bifold folds up in experiment.
The simulated deformation for a quarter of bifold structure.
Surface load � to simulates magnetic torque
Optimal Solution
Blood Perfusion
Electrical Conductivity
Thermal Conductivity
Constant properties
Effect of temperature dependent material properties
Radiofrequency Ablation for Abdominal Tumors
FE Modeling of Notched Unimorph
Analytical Modeling for Multi-Layers
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EAP: P(VDF-TrFE-CTFE) Adhesive Electrode Passive substrate
Multi-layered composite
Radius of curvature: Strain at y = 0 axis: e0
Cleared spot Breakdown spot
70 MV/m 100 MV/m
Project Overview
...
...
Unfold
Orignial meshAssemble
Overlapping analysis
Failed to fold
ClusteringSegmented mesh
UnfoldFailed to unfold
Fold
NetsContinuous folding
Mathematics of Folding
We gratefully acknowledge the support of the National Science Foundation EFRI grant number 1240459 and the Air Force Office of Scientific Research.
0 MV/m
30 MV/m 35 MV/m 40 MV/m 50 MV/m
Magnetically-Actuated Structures
The box configuration starts flat and achieves folding on the edges
The bifold starts from a flat state and folds under an applied magnetic field. This is simulated in COMSOL by coupling the magnetics module with the solid mechanics module.
Field strength increases
Students: Anil Erol, Wei Zhang, Saad Ahmed, Brad Hanks, Corey Breznak, Katherine Reichert, Logan Althoff, Landen Bowen, Brett Cowan, Zhonghua Xi, Sarah Masters, Erika Arrojado
-150
-100
-50
0
50
100
150
-25000 -20000 -15000 -10000 -5000 0 5000 10000 15000 20000 25000
Mag
net
izat
ion
(em
u/g
*)
Field Strength (Orsteds)
10% 15% 20% 25% 30% 35%
Magnetic Actuation Based on Hard Magnetics
Self-Clearing Increases Breakdown Field
Resin Pools
Magnetically aligned Resign Pool
The meso-scale bridges the micro- and macro-scales. An example of this is the Multi-Material DLP printer, which prints arbitrarily poled magneto-active materials in 3D; thus, the printer applies microsctructural alterations on large , complex structures
Electric Actuation: Dipole Interaction Based Electrostriction
Relaxor Ferroelectric Polymer Film of P(VDF-TrFE-CTFE) Amorphous region
Nano-polar region
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Barium Hexaferrite Particle Alignment
Magnetization hysteresis curves for varying volume fractions of barium hexaferrite in a PDMS matrix
A single particle is modeled as a discrete dipole
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• �′ and �′: azimuthal and polar angles (with respect to a cluster’s orientation, �� = ��� ,��� ,��� )
• ��: strength (magnitude) of dipole
The population of dipoles have an orientation-averaged moment density value Random � = 1/3 Aligned � = 0
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Folding/Curling of Notched Samples
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Orientations ����������� =
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Eight-chain hyperelastic model Dipole-dipole interaction energy
2. Multi-chain, a central dipole interacts with a probability distribution (PDF) of dipole densities
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1. Single chain, in which two dipoles interact, connected via an elastic chain
0
0.2
0.4
0.6
0.8
1
0 20 40 60 80 100
No
rmal
ized
Neg
ativ
e St
rain
E (MV/m)
Single Horizontal
Single Vertical
PDF - Horizontal
PDF - Vertical
Non-dimensionalized model compares single chain versus PDF approximations
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 20 40 60 80 100
-Str
ain
No
rmal
ized
E (MV/m)
PDF parameters are explored
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0
0.5
1
1.5
2
2.5
3
3.5
0 2000 4000 6000 8000 10000
-Str
ain
(%
)
E2 (MV/m)2
σ1 = 0.8 Experiments
C�
(GPa)
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(MV/m)
P(VDF-TrFE-CTFE) 150 2.5 8 0.08 0 25
Microstructure-Based Electrostriction Model
Conclusions
Trade space visualization
Multi-field simulations of a bimorph are developed by implementing electromechanical and magnetic constitutive equations into a 1D boundary value problem in which large deformations are achieved via Euler-Bernouilli beam equation
Notched unimorphs are modeled in COMSOL by shell elements, in which applying a pressure in the active layer simulates electrostriction
Shape Modeling International (SMI) 2016, also in Computer & Graphics [Xi and Lien]
0.5
0.6
0.7
0.8
0.9
1
0.05 0.15 0.25 0.35
Sq
ua
ren
ess
Volume Concentration of BHF
Re-config
Bunny-2206 Fish-2206
Each length scale provides vital components for a multi-field actuated Origami product. Material characterization is transferred into the meso-scale
to generate constitutive relations that are applied to 1D composite bending/folding, building a foundation for more complex 3D structures such
as transformers via stacking. Ongoing work involves the optimization of composite geometries and material configurations in simulations to achieve
target shapes for specific Origami applications