3D Printed Magnetorheological Elastomers

2017 ◽  
Author(s):  
Anil K. Bastola ◽  
Milan Paudel ◽  
Lin Li
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Damping Ratio ◽  
Shear Mode ◽  
Layer By Layer ◽  
Vibration Absorption ◽  
Spring Element ◽  
Elastomeric Matrix ◽  
3D Printed ◽  
Mr Effect

In this study, 3D printed magnetorheological (MR) elastomer has been characterized through a force vibration testing. The 3D printed MR elastomer is a composite consisting three different materials, magnetic particles and two different elastomers. The MR elastomers were printed layer-by-layer by encapsulating MR fluid within the polymeric elastomer and then allowed to cure at room temperature. The 3D printing allowed to print various patterns of magnetic particles within the elastomeric matrix. In the presence of an external magnetic field, both elastic and damping properties of the 3D printed MR elastomers were changed. Natural frequency, stiffness, damping ratio, damping coefficient, and shear modulus were increased with increasing magnetic field. For the single degree-of-freedoms system, shear mode MR elastomers suppressed the transmitted vibration amplitude up to 31.4% when the magnetic field was 550 mT. The results showed that the 3D printed MR elastomer could be used as a tunable spring element for vibration absorption or isolation applications. However, further optimization of the magnetic particles’ configurations should be performed to obtain the higher MR effect.

Patterned Magnetorheological Elastomer Developed by 3D Printing

2018 ◽  
Vol 939 ◽  
pp. 147-152 ◽  
Author(s):  
Anil K. Bastola ◽  
Milan Paudel ◽  
Lin Li
Keyword(s):  
Magnetic Field ◽  
3D Printing ◽  
Magnetic Particles ◽  
Layer By Layer ◽  
Carrier Fluid ◽  
Vibration Technique ◽  
Mode Of Operation ◽  
3D Printed ◽  
Mr Effect

This article delineates the characterization of the 3D printed MR elastomer through a forced vibration technique in the squeeze mode of operation. An anisotropic hybrid magnetorheological (MR) elastomer is developed via 3D printing. The 3D printed MR elastomer consists of three different materials; magnetic particles, magnetic particles carrier fluid, and an elastomer. MR fluid filaments are encapsulated layer-by-layer within the elastomer matrix using a 3D printer. When a moderately strong magnetic field is applied, the 3D printed MR elastomer changes its elastic and damping properties. The hybrid 3D printed MR elastomer also shows an anisotropic behavior when the direction of the magnetic field is changed with respect to the orientation of the printed filaments. The relative MR effect is higher when the applied magnetic field is parallel to the orientation of the printed filaments. The maximum change in the stiffness is observed to be 65.2% when a magnetic field of 500 mT is applied to the MR elastomer system. This result shows that the new method, 3D printing could produce anisotropic hybrid MR elastomers or possibly other types.

scholarly journals Magneto-Rheological Elastomer Composites. A Review

2020 ◽  
Vol 10 (14) ◽  
pp. 4899 ◽  
Author(s):  
Sneha Samal ◽  
Marcela Škodová ◽  
Lorenzo Abate ◽  
Ignazio Blanco
Keyword(s):  
Magnetic Field ◽  
Smart Materials ◽  
Mechanical Response ◽  
Viscoelastic Behavior ◽  
Shear Mode ◽  
Dynamic Shear ◽  
Elastomeric Matrix ◽  
Elastomer Composites ◽  
Magneto Rheological ◽  
Micro Structures

Magneto-rheological elastomer (MRE) composites belong to the category of smart materials whose mechanical properties can be governed by an external magnetic field. This behavior makes MRE composites largely used in the areas of vibration dampers and absorbers in mechanical systems. MRE composites are conventionally constituted by an elastomeric matrix with embedded filler particles. The aim of this review is to present the most outstanding advances on the rheological performances of MRE composites. Their distribution, arrangement, wettability within an elastomer matrix, and their contribution towards the performance of mechanical response when subjected to a magnetic field are evaluated. Particular attention is devoted to the understanding of their internal micro-structures, filler–filler adhesion, filler–matrix adhesion, and viscoelastic behavior of the MRE composite under static (valve), compressive (squeeze), and dynamic (shear) mode.

Integrated Dynamic Characteristics and Application in Semi-Active Dynamic Absorber of Magneto-Rheological Fluids

2012 ◽  
Vol 220-223 ◽  
pp. 601-606
Author(s):  
Shi Zhen Li ◽  
Gong Yu Li ◽  
Xiao Wu Kong ◽  
Jian Hua Wei
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Damping Ratio ◽  
Dynamic Test ◽  
Shear Mode ◽  
Vibration Absorption ◽  
New Type ◽  
Dynamic Absorber ◽  
Magneto Rheological ◽  
Squeeze Effect

As a new type of controllable rheological smart material, Magneto-rheological Fluids (MRF) are widely used in the field of vibration control. This article investigated their integrated dynamic characteristics in squeeze mode and shear mode. Two prototypes were designed and fabricated. The dynamic test for the two prototypes was performed on a simply supported beam vibrating device with the methods of drop-hammering and sweep-frequency measuring. The experimental results demonstrate that the damping ratio of the prototype in squeeze effect presents linearly and widely controllable from 0.0948 to 0.2268 with the increase of the coils’ excitation current, behaving as a variable MR damper. However, its natural frequency remains unchanged. It is also shown that the natural frequency of the prototype in shear effect increases significantly from 18Hz to 24 Hz, acting as a semi-active dynamic vibration (SDVA) absorber with broadband vibration absorption for the maximum attenuation of up to 74.3%. This study provides guidance for engineering applications of MRF.

Simulations on the rheology of dry magneto-rheological fluid under various working modes

2021 ◽  
Author(s):  
Lei Pei ◽  
Zongqiang Ma ◽  
Dongjun Ma ◽  
Xiaofeng Shi ◽  
Hao Pan ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
High Performance ◽  
Magnetic Particles ◽  
Simulation Method ◽  
Viscous Drag ◽  
Shear Mode ◽  
Particle Volume ◽  
Transient Vibration ◽  
The Matrix ◽  
Mr Effect

Abstract This work studied the rheological properties and magnetorheological (MR) mechanism of dry magnetorheological fluid (MRF) under various working modes. A novel simulation method combining the discrete element method and computational fluid dynamics was developed, in which the bilateral coupling between particles and the flow field of the matrix (air) was considered. The microstructures and mechanical properties in the redispersion process, shear mode, and valve mode were systematically simulated for the first time. The results indicated that dry MRF presented superior redispersion property and response time (several μs) than liquid-based MRFs. In shear mode, the magnetic dipolar force and friction force dominated the evolution of microstructures. In valve mode, the magnetic dipolar force and viscous drag force of air became the main interactions. Magnetic particles aggregated into sturdy chain structures and hindered the airflow. The MR effect in valve mode was the pressure gradient of the matrix, which increased up to 1.08×105 Pa/m with the increasing particle volume fractions and decreased under a large inflow velocity. The best MR effect in valve mode was achieved under a magnetic field of B=63 mT. Simulations revealed the influence of dimensionless Mn and Re number on the MR effect. The pressure gradient of the matrix was controlled by the external field and can be utilized to design a dry MRF valve for precious and transient vibration control. Simulated dimensionless shear stress in shear mode agreed well with experiments. This work will promote the development and applications of novel high-performance MRFs.

Line-patterned hybrid magnetorheological elastomer developed by 3D printing

2019 ◽  
Vol 31 (3) ◽  
pp. 377-388 ◽  
Author(s):  
AK Bastola ◽  
M Paudel ◽  
L Li
Keyword(s):  
Magnetic Field ◽  
3D Printing ◽  
Magnetic Particles ◽  
Dynamic Testing ◽  
Dynamic Properties ◽  
Magnetorheological Fluid ◽  
Magnetorheological Elastomers ◽  
3D Printed ◽  
Magnetorheological Effect ◽  
Printed Patterns

This article presents the development of line-patterned magnetorheological elastomers via 3D printing and their magnetorheological characterization. Herein, we consider five different patterns of magnetorheological fluid filaments that are printed and encapsulated within the elastomer matrix. The 3D-printed magnetorheological elastomers could represent the conventional isotropic and anisotropic magnetorheological elastomers. First, the effect of patterning the magnetorheological fluid filaments and the effect of change in the direction of the magnetic field is studied for all five patterns. Thereafter, the dynamic properties of 3D-printed magnetorheological elastomers under uniaxial deformation are presented. Magnetorheological effect shown by 3D-printed magnetorheological elastomers was found to be depended on the printed patterns as well as the direction of the applied magnetic field. This result showed that the 3D printing method has the potential to produce anisotropic magnetorheological elastomers or unique configuration of magnetic particles within the elastomer matrix. The dynamic testing showed that the storage modulus of 3D-printed magnetorheological elastomers is increased with increasing frequency and decreased with increasing strain amplitude, which signifies that the 3D-printed hybrid magnetorheological elastomers are also viscoelastic materials and the properties are magnetic field dependent as that of current magnetorheological elastomers.

scholarly journals Magnetorheological Effect of Magnetoactive Elastomer with a Permalloy Filler

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2371
Author(s):  
Dmitry Borin ◽  
Gennady Stepanov ◽  
Anton Musikhin ◽  
Andrey Zubarev ◽  
Anton Bakhtiiarov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Strains ◽  
High Loss ◽  
Elastomeric Matrix ◽  
Magnetorheological Effect ◽  
Size And Morphology ◽  
Mr Effect ◽  
Determining Factor ◽  
Individual Particles ◽  
Magnetoactive Elastomer

Within the frames of this study, the synthesis of a permalloy to be used as a filler for magnetoactive and magnetorheological elastomers (MAEs and MREs) was carried out. By means of the mechanochemical method, an alloy with the composition 75 wt.% of Fe and 25 wt.% of Ni was obtained. The powder of the product was utilized in the synthesis of MAEs. Study of the magnetorheological (MR) properties of the elastomer showed that in a ~400 mT magnetic field the shear modulus of the MAE increased by a factor of ~200, exhibiting an absolute value of ~8 MPa. Furthermore, we obtained experimentally a relative high loss factor for the studied composite; this relates to the size and morphology of the synthesized powder. The composite with such properties is a very perspective material for magnetocontrollable damping devices. Under the action of an external magnetic field, chain-like structures are formed inside the elastomeric matrix, which is the main determining factor for obtaining a high MR effect. The effect of chain-like structures formation is most pronounced in the region of small strains, since structures are partially destroyed at large strains. A proposed theoretical model based on chain formation sufficiently well describes the experimentally observed MR effect. The peculiarity of the model is that chains of aggregates of particles, instead of individual particles, are considered.

STUDY OF UTILIZABLE MAGNETORHEOLOGICAL ELASTOMERS

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4875-4882 ◽  
Author(s):  
X. L. GONG ◽  
L. CHEN ◽  
J. F. LI
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Carbonyl Iron ◽  
Zero Magnetic Field ◽  
Iron Particles ◽  
Magnetorheological Elastomers ◽  
Vibration Absorption ◽  
Tuned Vibration Absorbers ◽  
Roll Mill ◽  
Mr Effect

This paper presents two kinds of magnetorheological elastomers (MREs). One is composed of appropriate silicon rubber, carbonyl iron particles and some other materials. It is cured under a strong magnetic field at a room temperature. Its shear modulus change from 0.34MPa at zero magnetic field to 3.34MPa at 1T magnetic field, the relative MR effect reaches 878%. Such high MR effect has not been reported until now. The other is composed by appropriate natural rubber, carbonyl iron particles and some other materials. After the compositions are mixed in a two-roll mill, they are cured under a strong magnetic field according to a temperature profile. The increment of its modulus reaches 3.6MPa, and the relative modulus increment is 133%. Their mechanical properties are also evaluated. All observed results show that the fabricated MREs are utilizable. They have successfully been utilized to adaptive tuned vibration absorbers, which will serve for vibration absorption of vehicles.

Analysis of magneto rheological elastomers for energy harvesting systems

2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé
Keyword(s):  
Magnetic Field ◽  
Energy Harvesting ◽  
Shear Strain ◽  
Magnetic Induction ◽  
Magnetic Particles ◽  
Homogeneous Magnetic Field ◽  
Electrical Signal ◽  
Harvesting Systems ◽  
Dc Bias ◽  
Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

Fault Isolation of High Resistance Defects Using Comparative Magnetic Field Imaging

2003 ◽  
Author(s):  
Antonio Orozco ◽  
Elena Talanova ◽  
Anders Gilbertson ◽  
L.A. Knauss ◽  
Zhiyong Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Resistance ◽  
Integrated Circuit ◽  
Time Domain Reflectometry ◽  
Fault Isolation ◽  
Main Stream ◽  
Layer By Layer ◽  
Impedance Change ◽  
Resistance Change ◽  
Require Time

Abstract As integrated circuit packages become more complicated, the localization of defects becomes correspondingly more difficult. One particularly difficult class of defects to localize is high resistance (HR) defects. These defects include cracked traces, delaminated vias, C4 non-wet defects, PTH cracks, and any other package or interconnect structure that results in a signal line resistance change that exceeds the specification of the device. These defects can result in devices that do not run at full speed, are not reliable in the field, or simply do not work at all. The main approach for localizing these defects today is time domain reflectometry (TDR) [1]. TDR sends a short electrical pulse into the device and monitors the time to receive reflections. These reflections can correspond to shorts, opens, bends in a wire, normal interfaces between devices, or high resistance defects. Ultimately anything that produces an electrical impedance change will produce a TDR response. These signals are compared to a good part and require time consuming layer-by-layer deprocessing and comparison to a standard part. When complete, the localization is typically at best to within 200 microns. A new approach to isolating high resistance defects has been recently developed using current imaging. In recent years, current imaging through magnetic field detection has become a main-stream approach for short localization in the package [2] and is also heavily utilized for die level applications [3]. This core technology has been applied to the localization of high resistance defects. This paper will describe the approach, and give examples of test samples as well as results from actual yield failures.

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