Rheological Fluids for Energy Absorbing Systems

2013 ◽  
Vol 440 ◽  
pp. 13-18 ◽  
Author(s):  
Marcin Leonowicz ◽  
Joanna Kozłowska ◽  
Łukasz Wierzbicki
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Volume Fraction ◽  
Loss Modulus ◽  
Shear Thickening ◽  
High Viscosity ◽  
Polypropylene Glycol ◽  
Magneto Rheological ◽  
Energy Absorbing ◽  
Protective Performance

Two types of non-Newtonian fluids, magneto rheological (MRF) and shear thickening (STF) fluids, respectively were chosen as candidates for energy dissipation study in smart body armour. A series of magneto rheological fluids was synthesized on a basis of synthetic oil and carbonyl iron. The shear modules for the MRF containing 75 wt% of carbonyl iron, obtained in a magnetic field of 230 kA/m were as follows: complex shear modulus G* - 1.2 MPa, storage modulus G-1.2 MPa and loss modulus G 0.35 MPa. The studies revealed also that the silica fumed, dispersed in polypropylene glycol or polyethylene oxide, demonstrates shear thickening properties. The best combination of the properties (high viscosity, obtained at high shear rate) represents the material composed of the silica fumed (SF) and PEO300. Change of the volume fraction of the SF and variation of the molecular weight of the oligomer enables tailoring of the STF properties. Ballistic tests revealed that the structures containing PE bags with MRF (in magnetic field) or STF can enhance the protective performance of body armours providing their flexibility.

Composition – Property Relations in Shear Thickening Fluids

2014 ◽  
Vol 87 ◽  
pp. 91-97
Author(s):  
Łukasz Wierzbicki ◽  
Marcin Leonowicz
Keyword(s):  
High Strain ◽  
Volume Fraction ◽  
Solid Phase ◽  
Loss Modulus ◽  
Shear Thickening ◽  
Complex Viscosity ◽  
High Viscosity ◽  
Polypropylene Glycol ◽  
Shear Thickening Fluids ◽  
Composition Property

It was shown that fumed silica particles (FS), dispersed in polypropylene glycol (PPG), form shear thickening fluids (STF). PPGs with different molar mass were tested. The best combination of the properties (high viscosity, obtained at high shear rate) present the fluids composed of 7 nm FS and PPG 425. The highest volume fraction of FS, which was possible to disperse in PPG 425, was 25%. This fluid exhibited the highest viscosity. The highest magnitude of shear thickening effect was obtained, however, for 17.5 vol.% of the solid phase. Dynamic oscillatory shear experiments were conducted at either a constant amplitude or frequency. The constant strain amplitude tests showed, that for the frequency sweep, the systems showed viscous properties, except that of 25 vol.% of FS in PPG 425, which exhibited elastic properties in almost entire range of the frequency investigated. For the constant strain sweep, for low strains, the elastic modulus and loss modulus were hardly dependent on the strain, but for relatively high strain, this dependency was increasing. Also the complex viscosity was also growing for high strain values.

Tuning Active Magnetorheological Elastomers for Damping Applications

2010 ◽  
Vol 636-637 ◽  
pp. 766-771 ◽  
Author(s):  
Anna Boczkowska ◽  
Stefan F. Awietjan
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Volume Fraction ◽  
Iron Particles ◽  
Magnetorheological Elastomers ◽  
Ferromagnetic Component ◽  
Electron And Light Microscopy ◽  
Tan Δ ◽  
Microscopy Techniques ◽  
The Magnetic Field

Magnetorheological elastomers (MREs) were obtained by mixing soft polyurethane and carbonyl-iron particles. The effect of the volume fraction of the ferromagnetic particles on the MREs microstructure and properties, as well as their arrangement in relation to the external magnetic field were investigated. As a ferromagnetic component carbonyl–iron powder, with particle size from 6-9µm, was used. The amount of the carbonyl iron particles was varied from 1.5 to 33.0 %(v/v). The samples were produced with randomly dispersed and aligned carbonyl iron particles. Scanning electron and light microscopy techniques were used for the MRE microstructure observations. The rheological properties (G’, G’’ and tan δ) of the MRE were tested without and with the application of the magnetic field. It was found that the microstructure of MREs, particularly the amount and arrangement of the carbonyl-iron particles, has a significant influence on their rheological and damping properties.

Investigation on the Dynamic Shearing Characteristics of Magnetic Responsive Gel

2011 ◽  
Author(s):  
Katsuaki Sunakoda ◽  
Naoki Yamamoto ◽  
Hiroshi Nasuno ◽  
Hirohisa Sakurai
Keyword(s):  
Magnetic Field ◽  
Physical Properties ◽  
Storage Modulus ◽  
Smart Materials ◽  
Loss Modulus ◽  
Active Vibration Control ◽  
Hysteresis Loops ◽  
Active Vibration ◽  
Magneto Rheological ◽  
Dynamic Shearing

Material which would be largely changed its physical properties such as storage modulus and loss modulus under magnetic field has a potential of application on industrial fields. Magneto-rheological (MR) fluid has been widely studied since its viscosity is changed under magnetic field, but it is restricted for application of the industrial fields as it has liquid nature. Authors are proceeding with the development of magnetic responsive gels which contain the magnetic responsive particles in consideration of their prior studies. Three kinds of magnetic gels are selected and dynamic shearing characteristics are examined. Storage modulus and loss modulus are obtained under different dynamic frequencies and different magnetic fluxes. Some physical properties such as storage modulus and loss modulus are largely changed by applying magnetic field. The developed gels have an effect of energy dissipation, judging from hysteresis loops of stress-strain. And these smart materials have a potential of semi active vibration control materials.

scholarly journals Impact of the Carbon Nanofillers Addition on Rheology and Absorption Ability of Composite Shear Thickening Fluids

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3870
Author(s):  
Paulina Nakonieczna-Dąbrowska ◽  
Rafał Wróblewski ◽  
Magdalena Płocińska ◽  
Marcin Leonowicz
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Rheological Behavior ◽  
Shear Thickening ◽  
High Energy ◽  
Polypropylene Glycol ◽  
Shear Thickening Fluids ◽  
Carbon Nanofillers ◽  
Energy Absorbing ◽  
Composite Shear

Synthesis and characterization of composite shear thickening fluids (STFs) containing carbon nanofillers are presented. Shear thickening fluids have attracted particular scientific and technological interest due to their unique ability to abruptly increase viscosity in the case of a sudden impact. The fluids have been developed as a potential component of products with high energy absorbing efficiency. This study reports on the rheological behavior, stability, and microstructure of the STFs modified with the following carbon nanofillers: multi-walled carbon nanotubes, reduced graphene oxide, graphene oxide, and carbon black. In the current experiment, the basic STF was made as a suspension of silica particles with a diameter of 500 nm in polypropylene glycol and with a molar mass of 2000 g/mol. The STF was modified with carbon nanofillers in the following proportions: 0.05, 0.15, and 0.25 vol.%. The addition of the carbon nanofillers modified the rheological behavior and impact absorption ability; for the STF containing 0.25 vol.% of carbon nanotubes, an increase of force absorption up to 12% was observed.

scholarly journals Thermal stability of the elastomeric anti-trauma pad

2017 ◽  
Vol 19 (2) ◽  
pp. 93-100
Author(s):  
Karolina Olszewska ◽  
Dorota Zielinska ◽  
Marcin H. Struszczyk ◽  
Łukasz Wierzbicki ◽  
Marcin K. Leonowicz
Keyword(s):  
Aging Process ◽  
Volume Fraction ◽  
Accelerated Aging ◽  
Shear Thickening ◽  
Chemical Degradation ◽  
Polypropylene Glycol ◽  
Shear Thickening Fluid ◽  
Vis Spectroscopy ◽  
Ballistic Properties ◽  
Thermographic Analysis

AbstractThe elastomeric anti-trauma pad (EA-TP) based on shear thickening fluid (STF) has been developed. Dynamic oscillatory shear experiment was conducted at constant strain amplitude of 5%. STF composed of 25% of volume fraction of 7 nm Fumed Silica, dispersed in polypropylene glycol with molar mass 400 gmol−1shows elastic properties in entire investigated range of the frequency. Ballistic tests of EA-TP with 7.62 mm × 39 mm PS bullets were performed according to the PN-V-87000:2011 standard. The studies revealed about 60% reduction of the average backface signature depth (BSD) for the EA-TP, when compared to the nowadays commonly used soft insert. The ATR-FTIR analysis confirmed slight impact of the elevated temperature and air (oxygen) on the chemical degradation of the EA-TP surface. The UV-VIS spectroscopy has allowed to notice colour deviation of the aged samples towards green and yellow, as well as lack of dye resistance to accelerated aging process. Thermographic analysis has shown no visible changes of the EA-TP surface and sub-surface during accelerated aging process. The aforementioned small changes on the surface of EA-TP did not affect the ballistic properties of composite armour. EA-TP insert maintains ballistic properties after accelerated aging process which was simulating the period of 6 years according to ASTM F1980 – 07:2002 standard.

Magnetorheology of Multiwalled Carbon Nanotube Mineral Dispersions

2006 ◽  
Author(s):  
Zhengtao Yang ◽  
Ali Shaito ◽  
Nandika Anne D'Souza
Keyword(s):  
Magnetic Field ◽  
Carbon Nanotube ◽  
Power Law ◽  
Volume Fraction ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Mineral Oil ◽  
Multiwalled Carbon ◽  
Strain Sweep ◽  
Dynamic Yield

Multi-walled carbon nanotube (MWCNT) were dispersed in mineral oil and the magnetorheological response was measured. 0.5, 1.5 and 2.53 vol% nanotubes were dispersed in mineral oil. Strain sweep, frequency sweep, magneto sweep and steady shear tests were conducted in various magnetic field strengths. Storage modulus G', loss modulus G", complex viscosity η* and dynamic yield stress τy increased with magnetic field, which was partially attributed to the increasing degree of alignment of nanotubes in stronger magnetic field. G' and G" of MWCNT/mineral oil dispersions scaled with nanotube volume fraction φ by a power-law. The shear thinning behavior of MWCNT/mo dispersions followed the Ostwald-de Waele or power law.

Ultrasonic study of Si-oil based magneto-rheological fluid

2020 ◽  
Vol 75 (7) ◽  
pp. 657-663
Author(s):  
Chandreshvar Prasad Yadav ◽  
Dharmendra Kumar Pandey ◽  
Dhananjay Singh
Keyword(s):  
Magnetic Field ◽  
Iron Powder ◽  
Ultrasonic Velocity ◽  
Carbonyl Iron ◽  
Disperse Powder ◽  
Fixed Temperature ◽  
Mr Fluid ◽  
X Ray ◽  
Carbonyl Iron Powder ◽  
Magneto Rheological

AbstractThe present study is devoted to ultrasonic characterization of Si-oil based magneto-rheological (MR) fluid. Initially, the structural, morphological and magnetic properties of carbonyl iron powder have been carried out by its X-ray diffraction (XRD), scanning electron microscope (SEM), SEM-energy dispersive X-ray analyser (SEM-EDX) and vibrating sample magnetometer (VSM) measurements. The cubic structure with lattice parameter 2.841 Å of powdered material is confirmed by XRD study while spherical particle content is confirmed by SEM measurement. The VSM measurement of powder endorses the smooth magnetization and demagnetization with no remnance and coercivity. The rheological and ultrasonic properties are measured for pure Si-oil and four synthesized MR fluids having 10–40 wt% of carbonyl iron powder. The density and viscosity of synthesized MR fluid is found to enhance with weight percentage of carbonyl iron powder. In absence of magnetic field, the longitudinal ultrasonic velocity is found to decay with temperature and concentration. In presence of magnetic field, the longitudinal ultrasonic velocity is found to enhance while velocity measured at transverse magnetic field is found to decay for each MR fluid. The change in ultrasonic velocity with concentration at fixed temperature or magnetic field resembles the magnetization characteristics of disperse powder in MR fluid. The study opens a new dimension for its characterization through ultrasonic non-destructive technique.

scholarly journals Discontinuous shear thickening in concentrated suspensions

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180211 ◽  
Author(s):  
Georges Bossis ◽  
Olga Volkova ◽  
Yan Grasselli ◽  
Oumar Gueye
Keyword(s):  
Magnetic Field ◽  
Shear Rate ◽  
Applied Stress ◽  
Volume Fraction ◽  
Shear Thickening ◽  
Solid Particles ◽  
Concentrated Suspensions ◽  
Stick Slip ◽  
Frictional Contacts ◽  
Jamming Transition

The flow of concentrated suspensions of solid particles can be suddenly blocked by the formation of a percolated network of frictional contacts above a critical value of the applied stress. Suspensions of magnetic particles coated with a superplastifier molecule were shown to produce a strong jamming transition. We find that, for these suspensions with an abrupt discontinuous shear thickening, a model using the divergence of the viscosity at a volume fraction that depends on the applied stress does not well describe the observed behaviour both below and above the critical stress. At a constant applied stress above the critical one, we have a stick–slip behaviour of the shear rate whose period can be predicted and scaled as the square root of the relaxation time of the frictional contacts. The application of a small magnetic field allows us to continuously decrease the critical shear rate, and it appears that the yield stress induced by the magnetic field does not contribute to the jamming transition. Finally, it is shown that this jamming transition also appears in the extrusion of a suspension through a die, but with a much slower dynamics than in the case of stress imposed on a rotational geometry. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

Application Research Development of Smart Materials on Personnel Armor Protective Materials

2014 ◽  
Vol 1004-1005 ◽  
pp. 1396-1400
Author(s):  
Jun Liu ◽  
Dang Sheng Xiong ◽  
Bin Li
Keyword(s):  
Chemical Reaction ◽  
Smart Materials ◽  
Shear Thickening ◽  
Research Development ◽  
Application Research ◽  
Shear Thickening Fluids ◽  
Magneto Rheological ◽  
Protective Performance

Integration of smart materials such as field-responsive fluid, i.e. Electro-rheological (ER) , magneto-rheological (MR) and shear thickening fluids (STFs), into armor protective materials, may probably solve the problem between its portability and protective performance. The wide applications of three fluids are described in brief in this paper, and research developments (especially STFs’ in detail) of armor protective materials strengthened by utilizing three fluids or chemical reaction material are summarized. Analysises are made of the questions faced by these composites researches. The foreground is talked about in the end.

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.

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