Multi-Field Responsive Origami Structures: Preliminary Modeling and Experiments

2013 ◽  
Author(s):  
Saad Ahmed ◽  
Carlye Lauff ◽  
Adrienne Crivaro ◽  
Kevin McGough ◽  
Robert Sheridan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Compliant Mechanisms ◽  
Active Material ◽  
Space Structures ◽  
Research Directions ◽  
3 Dimensional ◽  
Active Structures ◽  
Physical Testing ◽  
Opposite Field ◽  
Modeling And Experiments

The use of origami principles to create 3-dimensional shapes has the potential to revolutionize active material structures and compliant mechanisms. Active origami structures can be applied to a broad range of areas such as reconfigurable aircraft and deployable space structures as well as instruments for minimally invasive surgery. Our current research is focused on dielectric elastomer (DE) and magneto active elastomer (MAE) materials to create multi-field responsive structures. Such multi-field responsive structures will integrate the DE and MAE materials to enable active structures that fold/unfold in different ways in response to electric and/or magnetic field. They can also unfold either as a result of eliminating the applied field or in response to the application of an opposite field. This concept is demonstrated in a folding cube shape and induced locomotion in the MAE material. Two finite element models are developed for both the DE and MAE materials and validated through physical testing of these materials. The models are then integrated to demonstrate multi-field responses of a bi-fold multi-field responsive structure. The bifold model is designed to fold about one axis in an electric field and a perpendicular axis in a magnetic field. Future modeling efforts and research directions are also discussed based on these preliminary results.

Magneto-Elastic Compliant Mechanisms

2001 ◽  
Author(s):  
Janarthanan Venkataraghavan ◽  
Arun R. Srinivasa
Keyword(s):  
Magnetic Field ◽  
Degrees Of Freedom ◽  
Conceptual Models ◽  
Compliant Mechanisms ◽  
Mechanical Energy ◽  
Active Material ◽  
Electromagnetic Energy ◽  
Physical Contact ◽  
Peristaltic Pump ◽  
The Cost

Abstract The motivation for this work has been a variety of motions like navigation of pipelines, insertion operations in assembly, and gripping actions, which require the adaptation of the mechanism to the external constraints, rather than avoid them. To this effect, efforts have been made towards building mechanisms that obtain the required degrees of freedom through deformations rather than explicit joints in them. Although the use of many joints provides the required number of degrees of freedom, it does so at the cost of making the system very bulky and complex. With the advent of new polymers, the possibility of building such mechanisms without joints, that fulfil the requirements of adaptation, have increased. Based on this approach, a Magneto Active Polymer (MAP) material has been developed in-house at the Texas A&M University, in which the actuation is performed by the conversion of electromagnetic energy into mechanical energy. The initial experimentation has proved the vast potential of the use of such a material, and a few mechanisms, like a magneto active peristaltic pump, have already been developed and tested, using this material. In this mechanism the pumping action is obtained when a moving magnetic field produces peristaltic waves in the magneto active material shaped as a tube. These waves help in pushing the fluid forward, in the tube. The advantage of this mechanism is that there is not physical contact of the actuating mechanism an the MAP tube, thereby reducing the wear. In developing the design for the peristaltic pump and other conceptual models described in this paper, ideas have been drawn from the different modes of locomotion and actuators used, in lower organisms and these have been good sources of inspiration for the work detailed in this paper.

Effects of a High Magnetic Field on the Growth of 3-Dimensional Silver Dendrites

2004 ◽  
Vol 77 (2) ◽  
pp. 275-279 ◽  
Author(s):  
Akio Katsuki ◽  
Ichiro Uechi ◽  
Yoshifumi Tanimoto
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
3 Dimensional ◽  
Silver Dendrites

scholarly journals The formation of relativistic plasma structures and their potential role in the generation of cosmic ray electrons

2008 ◽  
Vol 15 (6) ◽  
pp. 831-846 ◽  
Author(s):  
M. E. Dieckmann
Keyword(s):  
Magnetic Field ◽  
Phase Space ◽  
Magnetic Energy ◽  
Ion Beam ◽  
Cosmic Ray ◽  
Compact Objects ◽  
Space Structures ◽  
Magnetic Field Generation ◽  
Particle In Cell ◽  
Field Generation

Abstract. Recent particle-in-cell (PIC) simulation studies have addressed particle acceleration and magnetic field generation in relativistic astrophysical flows by plasma phase space structures. We discuss the astrophysical environments such as the jets of compact objects, and we give an overview of the global PIC simulations of shocks. These reveal several types of phase space structures, which are relevant for the energy dissipation. These structures are typically coupled in shocks, but we choose to consider them here in an isolated form. Three structures are reviewed. (1) Simulations of interpenetrating or colliding plasma clouds can trigger filamentation instabilities, while simulations of thermally anisotropic plasmas observe the Weibel instability. Both transform a spatially uniform plasma into current filaments. These filament structures cause the growth of the magnetic fields. (2) The development of a modified two-stream instability is discussed. It saturates first by the formation of electron phase space holes. The relativistic electron clouds modulate the ion beam and a secondary, spatially localized electrostatic instability grows, which saturates by forming a relativistic ion phase space hole. It accelerates electrons to ultra-relativistic speeds. (3) A simulation is also revised, in which two clouds of an electron-ion plasma collide at the speed 0.9c. The inequal densities of both clouds and a magnetic field that is oblique to the collision velocity vector result in waves with a mixed electrostatic and electromagnetic polarity. The waves give rise to growing corkscrew distributions in the electrons and ions that establish an equipartition between the electron, the ion and the magnetic energy. The filament-, phase space hole- and corkscrew structures are discussed with respect to electron acceleration and magnetic field generation.

Development of Multi-Ferroic Actuator/Sensor Material and Device for Intelligent/Smart Technology - Basic Design and Experimental Verification

2008 ◽  
Vol 54 ◽  
pp. 187-194 ◽  
Author(s):  
Yasubumi Furuya ◽  
Teiko Okazaki
Keyword(s):  
Magnetic Field ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
High Speed ◽  
Large Scale ◽  
Coupling Effect ◽  
Active Material ◽  
Smart Technology ◽  
Internal Damage ◽  
Composite Actuator

Technical importance of multi-ferroic approach for designing advanced multi-functional actuator/sensors based on a mutual coupling effect between ferroic material elements is pointed out for intelligent/smart technology. Two types of multi-ferroic actuator/sensor devices. i.e. (1) magnetically driven composite actuator and (2) multi-functional surface acoustic wave (SAW) sensor by MEMS are presented. First, a large-scale robust composite actuator is the composite structure which is reinforced by the superelastic fiber or lamellar of shape memory alloys (TiNi) in the ferromagnetic metal (Ni) matrix. This multi-ferroic composite can be driven with high speed as well as considerably enhanced strain by applying a wireless magnetic field. Secondarily, multi-functionally designed, multi-ferroic senor device using surface acoustic wave (SAW) is introduced. On the surface part between IDTs, environmentally active material films such as SMA, FSMA, magnetostrictive alloy etc. are formed by magnetron-sputtering. Various environmental sensing parameters i.e. temperature, magnetic field strength, stress, loading hysteresis and internal damage etc. can be evaluated nondestructively from the signal analysis of amplitude and phase change of SAW. Consequently, these results show the promising new types of multi-functional composite actuator and sensor based on multi-ferroic effect.

Magnetic Field Within a Magnetic Shape Memory Alloy and an Equivalent Uniform Applied Magnetic Field for Model Input

2017 ◽  
Author(s):  
J. Lance Eberle ◽  
Heidi P. Feigenbaum ◽  
Constantin Ciocanel
Keyword(s):  
Magnetic Field ◽  
Shape Memory ◽  
Applied Field ◽  
Volume Fraction ◽  
Unit Cell ◽  
Uniform Field ◽  
Magnetic Shape Memory ◽  
Twin Boundaries ◽  
Short Side ◽  
3 Dimensional

Magnetic shape memory alloys (MSMAs) exhibit recoverable strains of up to 10% due to reorientation of their martensitic tetragonal unit cell. A stress or magnetic field applied to the material will cause the short side of the unit cell (which is approximately aligned with the magnetic easy axis) to align with the input to the material, resulting in an apparent plastic strain. This strain can be fully recovered by an applied stress or magnetic field in a perpendicular direction. When the martensitic variants reorient, twin boundaries, which separate the different variants, form and move throughout the specimen. A number of models have been proposed for MSMAs and many of these models are homogenized, i.e. the models do not account for twin boundaries, but rather account for the volume fraction of material in each variant. These types of models often assume that the MSMA is subject to a uniform field so that there is no appreciable difference in the volume fraction of variants in each location. In this work, we address the issue of how these models can be used when the field is not uniform. In particular, we look at the experiments from Feigenbaum et al., in which a MSMA trained to accommodate three variants, was subject to 3-dimensional magneto-mechanical loading. Due to experimental constraints, the field applied to the MSMA was not uniform. In this work, to understand the actual field distribution during experiments, we performed a high-resolution 3-dimensional finite element analysis (FEA) of the magnetic field experienced by the MSMA sample. The FEA allowed us to determine how non-uniform the experimentally applied field was and the differences between the applied field and the field experienced by the MSMA. Furthermore, we use the FEA to determine the average field experienced by the MSMA, and identify an equivalent uniform applied field that could serve as input for the model. For the latter, we seek a uniform magnetic field which gives similar magnetic field within the MSMA specimen as the true experimental conditions.

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