Magnetorheological Damping of Fragment Barrier Suspension Systems

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Kwon Joong Son ◽  
Eric P. Fahrenthold
Keyword(s):  
Ballistic Performance ◽  
Mr Fluid ◽  
Suspension Systems ◽  
Mr Fluids ◽  
Ballistic Protection ◽  
Protection Systems ◽  
Fluid Damping ◽  
Magnetorheological Damping ◽  
Impact Experiments ◽  
Very High

Magnetorheological (MR) fluids, well established as components of a variety of suspension systems, may offer opportunities to improve the performance of fabric ballistic protection systems, which typically do not incorporate significant energy dissipation mechanisms. A series of ballistic impact experiments has been conducted to investigate the potential of MR fluid damped fabric suspension systems to improve upon current fabric barrier designs. The results indicate that for the simple fabric suspension systems tested, MR fluid damping does not improve upon the very high weight specific ballistic performance of state of the art aramid fibers.

Boron Carbide-Silicon Carbide Laminated Ceramics for Ballistic Protection

Materials ◽  
2003 ◽  
Author(s):  
N. Orlovskaya ◽  
J. Adams ◽  
M. Chheda ◽  
J. Shih ◽  
S. Yarmolenko ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Residual Stresses ◽  
Boron Carbide ◽  
Ceramic Composites ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Ballistic Performance ◽  
Ballistic Protection ◽  
Impact Experiments

The paper describes the development of tough boron carbide-silicon carbide ceramic laminates with enhanced ballistic performance for armor application. Laminates with strong interfaces can provide high fracture toughness and damage tolerance along with improved ballistic protection. The enhancement of the mechanical/ballistic performance of laminates is obtained through design of controlled residual stresses in separate layers. The research produced a fundamental knowledge of the interrelationships between processing, residual stresses, and mechanical behavior of boron carbide based multilayered ceramic composites with an enhanced understanding of laminate’s fracture toughness, strength, and Young’s modulus. It was expected that the newly developed laminates would have necessary mechanical properties to increase maximum critical velocity of dwell/penetration transition during impact experiments.

scholarly journals Analytical investigation of high-velocity impact on hybrid unidirectional/woven composite panels

2016 ◽  
Vol 30 (4) ◽  
pp. 545-563 ◽  
Author(s):  
H Shanazari ◽  
GH Liaghat ◽  
H Hadavinia ◽  
A Aboutorabi
Keyword(s):  
Cross Sections ◽  
Shear Failure ◽  
Failure Criteria ◽  
Analytical Investigation ◽  
Woven Fabrics ◽  
Body Armor ◽  
Ballistic Performance ◽  
Nonwoven Fabrics ◽  
Ballistic Protection ◽  
Maximum Tensile Strain

In addition to fiber properties, the fabric structure plays an important role in determining ballistic performance of composite body armor textile. Textile structures used in ballistic protection are woven fabrics, unidirectional (UD) fabric structures, and nonwoven fabrics. In this article, an analytical model based on wave propagation and energy balance between the projectile and the target is developed to analyze hybrid fabric panels for ballistic protection. The hybrid panel consists of two types of structure: woven fabrics as the front layers and UD material as the rear layers. The model considers different cross sections of surface of the target in the woven and UD fabric of the hybrid panel. Also the model takes into account possible shear failure by using shear strength together with maximum tensile strain as the failure criteria. Reflections of deformation waves at interface between the layers and also the crimp of the yarn are modeled in the woven part of the hybrid panel. The results show greater efficiency of woven fibers in front layers (more shear resistance) and UD yarns in the rear layers (more tensile resistance), leading to better ballistic performance. Also modeling the yarn crimp results in more trauma at the backface of the panel producing data closer to the experimental results. It was found that there is an optimum ratio of woven to UD materials in the hybrid ballistic panel.

scholarly journals Squeezing Force of the Magnetorheological Fluid Isolating Damper for Centrifugal Fan in Nuclear Power Plant

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Jin Huang ◽  
Ping Wang ◽  
Guochao Wang
Keyword(s):  
Nuclear Power ◽  
Theoretical Foundation ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Magnetorheological Fluid ◽  
Centrifugal Fan ◽  
Parallel Channel ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Control Devices

Magnetorheological (MR) disk-type isolating dampers are the semi-active control devices that use MR fluids to produce controllable squeezing force. In this paper, the analytical endeavor into the fluid dynamic modeling of an MR isolating damper is reported. The velocity and pressure distribution of an MR fluid operating in an axisymmetric squeeze model are analytically solved using a biviscosity constitutive model. Analytical solutions for the flow behavior of MR fluid flowing through the parallel channel are obtained. The equation for the squeezing force is derived to provide the theoretical foundation for the design of the isolating damper. The result shows that with the increase of the applied magnetic field strength, the squeezing force is increased.

Internal Organizational Measurement for Control of Magnetorheological Fluid Properties

2006 ◽  
Vol 129 (4) ◽  
pp. 423-428 ◽  
Author(s):  
John R. Lloyd ◽  
Miquel O. Hayesmichel ◽  
Clark J. Radcliffe
Keyword(s):  
Magnetic Field ◽  
Physical Properties ◽  
High Sensitivity ◽  
Time Varying ◽  
Measurable Effect ◽  
Mr Fluid ◽  
Fluid State ◽  
Mr Fluids ◽  
Fluid Properties ◽  
Field Excitation

Magnetorheological (MR) fluids change their physical properties when subjected to a magnetic field. As this change occurs, the specific values of the physical properties are a function of the fluid’s time-varying organization state. This results in a nonlinear, hysteretic, time-varying fluid property response to direct magnetic field excitation. Permeability, resistivity and permittivity changes of MR fluid were investigated and their suitability to indicate the organizational state of the fluid, and thus other transport properties, was determined. High sensitivity of permittivity and resistivity to particle organization and applied field was studied experimentally. The measurable effect of these material properties can be used to implement an MR fluid state sensor.

Effect of Centrifugal Force Effect on Magneto-Rheological Fluid Clutches

2002 ◽  
Author(s):  
Vijay A. Neelakantan ◽  
Gregory N. Washington
Keyword(s):  
Magnetic Fields ◽  
Design Methodology ◽  
Volume Fraction ◽  
The Other ◽  
Particle Orientation ◽  
Centrifugal Forces ◽  
Mr Fluid ◽  
Set Up ◽  
Magneto Rheological ◽  
Very High

The property of magnetorheological fluids to change their yield stress depending on applied magnetic fields can be employed to develop many controllable devices one of them being MR fluid based clutches. One major problem however with MR fluid based clutches is that at high rotational speeds, the iron/ferrous particles in the MR fluid centrifuge due to very high centrifugal forces. Thus the particles move outward as the speed increases thereby making the fluid non-homogeneous. Many times however the initial analysis assumes fluid homogeneity, which is really not the case. In this paper this problem is addressed by assuming various volume fraction profiles describing the fluid particle orientation. Two cases, one with a linear profile and the other with an exponential profile are discussed. Expressions for the torque transmitted are derived at for both disc shaped and cylindrical shaped clutches. In addition, the use of a MR sponge based clutch that may indeed reduce the effect of centrifugal forces significantly is described. The design methodology and configuration for the sponge clutch are also discussed. An experimental set up used to test the clutch is also described.

Development of a boring bar with magneto rheological fluid damping and assessment of its dynamic characteristics

2017 ◽  
Vol 24 (14) ◽  
pp. 3094-3106 ◽  
Author(s):  
CV Biju ◽  
MS Shunmugam
Keyword(s):  
Modal Parameters ◽  
Model Parameters ◽  
Excitation Current ◽  
Mr Fluid ◽  
Boring Bar ◽  
Chatter Suppression ◽  
Damping Characteristics ◽  
Fluid Damping ◽  
Variable Damping ◽  
Magneto Rheological

The boring operation is prone to chatter as the boring bar is slender and has an overhang. For chatter suppression, passive, semi-active or active control methods can be employed. In the present work, a boring bar has been specially designed to transfer vibration to a cantilever bar surrounded by magneto rheological (MR) fluid. The MR fluid when exposed to electromagnetic flux changes its rheological property within a certain range. Thus, the boring bar is able to exhibit variable damping characteristics by changing the excitation current. The modal parameters are experimentally obtained through an impact test and a shaker test. The variation of modal parameters with excitation current is discussed. A stability lobe diagram is also developed from the model parameters, showing safe and unsafe regions for operation. The semi-active boring bar developed in the present work can be used for the suppression of chatter during the boring operation.

Effect of Internal Pressure on Flow Properties of Magnetorheological Fluids

2011 ◽  
Author(s):  
Andrea Spaggiari ◽  
Eugenio Dragoni
Keyword(s):  
Internal Pressure ◽  
System Design ◽  
Flow Mode ◽  
Shear Mode ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Experimental Apparatus ◽  
Gear Pumps ◽  
Strengthen Effect ◽  
Hydraulic System Design

Magnetorheological (MR) fluids have a lot of applications in the industrial world, but sometimes their properties are not performing enough to meet system requirements. It has been found that in shear mode MR fluids exhibits a pressure dependency called squeeze strengthen effect. Since a lot of MR fluid based devices work in flow mode (i.e. dampers) this paper investigates the behaviour in flow mode under pressure. The system design is articulated in three steps: hydraulic system design, magnetic circuit design and design of experiment. The experimental apparatus is a cylinder in which a translating piston displaces the fluid without the use of standard gear pumps, incompatible with MR fluids. The experimental apparatus measures the MR fluid yield stress as a function of pressure and magnetic field allowing the yield shear stress to be calculated. A statistical analysis of the results shows that the squeeze strengthen effect is present in flow mode as well and the presence of internal pressure is able to enhance the performance of MR fluid by nearly ten times.

Influence of the Laminate Configurations of Transparent Armor on its Ballistic Protection

2014 ◽  
Vol 608 ◽  
pp. 253-258 ◽  
Author(s):  
Priawthida Jantharat ◽  
Ryan C. McCuiston ◽  
Chaiwut Gamonpilas ◽  
Sujarinee Kochawattana
Keyword(s):  
Experimental Results ◽  
Front Face ◽  
Light Weight ◽  
Ballistic Performance ◽  
User Requirement ◽  
Element Analysis ◽  
Minimum Requirement ◽  
National Institute Of Justice ◽  
Ballistic Protection ◽  
High Level

The ballistic performance of transparent armors has been continuously developed for an application on security purposes. Generally, ballistic performance of the laminated glass increases with its thickness and weight while the user requirement prefers high level of ballistic protection with thin and light weight body. In this study, fabrication of light weight glass-PVB transparent armors with the level-3 protection according to the National Institute of Justice (NIJ) standard was attempted. The ballistic performances of various configurations of glass-PVB laminates were determined against 7.62 mm ammunitions. Results from fragmentation analysis indicated the influence of glass-sheet-arrangement in the armor structures on the ballistic damages. The minimum requirement on the thickness of front-face layer was also discussed. To verify the experimental results, finite element analysis was performed on all laminated systems. It was found that the results from computational analysis were in reasonable agreement with the experimental results.

Experimental studies on magnetorheological brake containing plane, holed and slotted discs

2017 ◽  
Vol 69 (2) ◽  
pp. 116-122 ◽  
Author(s):  
Chiranjit Sarkar ◽  
Harish Hirani
Keyword(s):  
Experimental Studies ◽  
State Condition ◽  
Frictional Torque ◽  
Iron Particles ◽  
Low Friction ◽  
Mr Fluid ◽  
Content Type ◽  
Shear Rates ◽  
Mr Fluids ◽  
Braking Torque

Purpose This study aims to design an ideal magnetorheological (MR) brake that exerts negligible frictional torque in the off-state condition and controllable frictional torque in the on-state condition. Design/methodology/approach Silicone-based MR fluid, containing 9 per cent volume carbonyl iron particles, has been synthesized and used. The synthesized MR fluid is advantageous in maintaining low friction losses in off-state conditions. A magneto-rheometer has been utilized to characterize the off-state viscosity of the MR fluid at variable shear rates and shear stress of MR fluids at various magnetic fields. A mechanism to enhance the braking torque in the on-state condition has been designed and developed. An experimental test rig has been developed to capture the torque characteristics of the developed MR brakes. Three different designs of MR discs have been experimented under a magnetic field varying from 0 to 375 kA/m. Experimental results of braking torque under shear and compression modes have been presented. Findings Slotted disc MR brake gives much better torque performance. Originality/value The braking torque results motivate to use the slotted disc MR brake for high torque application.

Thermal and tribological performance of graphite flake based magnetorheological fluid under shear mode clutch

2021 ◽  
pp. 1-24
Author(s):  
Manish Kumar Thakur ◽  
Chiranjit Sarkar
Keyword(s):  
Research Work ◽  
Magnetorheological Fluid ◽  
Tribological Performance ◽  
Graphite Flake ◽  
Shear Mode ◽  
Torque Sensor ◽  
Test Rig ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Torque Transmission

Abstract In this research work, graphite flake has been used as an additive in magnetorheological (MR) fluid to improve its thermal and tribological performance. MR fluids with varying amounts of graphite flakes (0.5, 1, 2, 3, 4, and 5 wt%) are prepared to show effective thermal and tribological performance. A test rig is developed with a DC motor, torque sensor, and MR clutch operated in a shear mode to test the torque transmission. Results show the lubrication effects of graphite flakes in MR fluid. Torque transmission is improved in on-state and off-state using graphite flakes based MR fluid as compared to conventional MR fluid. Heating of MR clutch is also reduced with the graphite flakes based MR fluid. Wear marks and damages are decreased significantly with the increased amount of graphite flakes as found in surface roughness tests. SEM and EDS are used to characterize the worn surfaces. This research provides information about the effectiveness of graphite flakes in the MR clutch to improve the device's performance.

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