Effect of the yarn pull-out velocity of shear thickening fluid-impregnated Kevlar fabric on the coefficient of friction

2016 ◽  
Vol 30 (8) ◽  
pp. 3559-3565 ◽  
Author(s):  
Sh. Alikarami ◽  
N. Kordani ◽  
A. SadoughVanini ◽  
H. Amiri
Keyword(s):  
Coefficient Of Friction ◽  
Shear Thickening ◽  
Shear Thickening Fluid ◽  
Pull Out ◽  
The Coefficient Of Friction

scholarly journals Effect of nano-solid particles on the mechanical properties of shear thickening fluid (STF) and STF-Kevlar composite fabric

2021 ◽  
Vol 16 ◽  
pp. 155892502110448
Author(s):  
Mingmei Zhao ◽  
Jinqiu Zhang ◽  
Zhizhao Peng ◽  
Jian Zhang
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Tensile Force ◽  
Shear Thickening ◽  
Solid Particles ◽  
Time Range ◽  
Shear Thickening Fluid ◽  
Pull Out ◽  
Diamond Particles

To analyze the effect of nano-solid particles on the mechanical properties of shear thickening fluid (STF) and its Kevlar composite fabric. In this study, nano-silica and polyethylene glycol (PEG 200) were used as dispersed and continuous phases. Nano-graphite and nano-diamond particles were used as additives to prepare STF and Kevlar composite fabric. Study the friction characteristics and rheological characteristics of STF at different temperatures. Explore the STF’s mechanical response under transient high-speed impact conditions through the split Hopkinson pressure bar experiment. The mechanical properties of STF-Kevlar fabric are studied through yarn pull-out test and burst experiments. The experimental results show that the intermolecular repulsive force of STF is enhanced under a high-temperature environment, and shear thickening effect is reduced. Nano-diamond particles strengthen the contact coupling force and contact probability between the particle clusters, so that the maximum viscosity of the system reaches 1679 Pa s, the thickening ratio reaches 318 times, and the rheological properties of the shear thickening fluid are improved. The results of the SHPB experiment show that the STF can complete a dynamic response within a 50–75 µs time range, and the maximum stress can reach 78 MPa. The bullet’s incident kinetic energy is not only transformed into thermal energy and phase change energy of solid-liquid conversion, but also into frictional energy between particles. The mechanical experiments of STF-Kevlar composite fabrics show that the tensile force value of STF5-Kevlar is the largest (10.3 N/13.5 N), and the tensile force of neat Kevlar was the smallest (4.3 N/4.9 N). The maximum bearing capacity (0.3 kN) and absorption energy (51.8 J) of Neat Kevlar are less than those of STF1-Kevlar (3.2 kN, 116.7 J) and STF3-Kevlar (1.9 kN, 88.2 J), and STF5-Kevlar (4.7 kN, 143.3 J). Fabric’s failure mode is converted from partial yarn extraction to overall deformation and rupture of the fabric. Therefore, by changing the solid additives’ parameters, the STF and the composite fabric’s mechanical properties can be effectively controlled, which provides a reference for preparing the STF and fabric composite materials.

scholarly journals Experimental and numerical analysis of high and low velocity impacts against neat and shear thickening fluid (STF) impregnated weave fabrics

2018 ◽  
Vol 183 ◽  
pp. 01044
Author(s):  
Djalel Eddine Tria ◽  
Larbi Hemmouche ◽  
Abdelhadi Allal ◽  
Abdelkader Benouali
Keyword(s):  
High Velocity ◽  
Shear Thickening ◽  
Force Sensor ◽  
Low Velocity Impact ◽  
Dynamic Force ◽  
Low Velocity ◽  
Shear Thickening Fluid ◽  
Velocity Impact ◽  
Pull Out ◽  
The Impact

This investigation aims to study the efficiency of STF impregnated plain-weave fabric made of Kevlar under high and low velocity impact conditions. The shear thickening fluid (STF) was prepared by ultrasound irradiation of silica nanoparticles (diameter ≈30 nm) dispersed in liquid polyethylene glycol polymer. STF impregnation effect was determined from single yarn pull-out test and penetration at low velocity using drop weight machine equipped with hemi-spherical penetrator and dynamic force sensor. Force-displacement curves of neat and impregnated Kevlar were analysed and compared. Also, the STF impregnation effect on Kevlar multilayers was analysed from high velocity impact tests using 9mm FMJ bullet at 390 m/s. After impact, Back face deformation (BFD) of neat and impregnated Kevlar layers were measured and compared. Results showed that STF impregnated fabrics have better energy absorption and penetration resistance as compared to neat fabrics without affecting the fabric flexibility. When relative yarn translations are restricted (e.g. at very high levels of friction), windowing and yarn pull-out cannot occur, and the fibres engaged with the projectile fail in tension that leads to fabric penetration. Microscopy of these fabrics after testing have shown pitting and damage to the Kevlar filaments caused by the hard silica particles used in the STF. Mesoscopic 3D Finite Element models were developed using explicit LS-DYNA hydrocode to account for STF impregnation by employing the experimental results of yarn pull-out tests, low and high velocity impacts. It was found that friction between fibers and yarns increase the dissipation of energy upon impact by restricting fiber mobility, increasing the energy required for relative yarn translations and transferring the impact energy to a larger number of fibers.

scholarly journals Shear-Thickening Fluid Using Oxygen-Plasma-Modified Multi-Walled Carbon Nanotubes to Improve the Quasi-Static Stab Resistance of Kevlar Fabrics

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1356 ◽  
Author(s):  
Danyang Li ◽  
Rui Wang ◽  
Xing Liu ◽  
Shu Fang ◽  
Yanli Sun
Keyword(s):  
Carbon Nanotubes ◽  
Loss Modulus ◽  
Shear Thickening ◽  
Woven Fabrics ◽  
Body Armor ◽  
Shear Thickening Fluid ◽  
Pull Out ◽  
Stab Resistance ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The excellent mechanical property and light weight of protective materials are vital for practical application in body armor. In this study, O2-plasma-modified multi-walled carbon nanotubes (M-MWNTs) were introduced into shear-thickening fluid (STF)-impregnated Kevlar woven fabrics to increase the quasi-static stab resistance and decrease the composite weight. The rheological test showed that the addition of 0.06 wt. % M-MWNT caused a marked increase in the peak viscosity from 1563 to 3417 pa·s and a decrease in the critical shear rate from 14.68 s−1 to 2.53 s−1. The storage modulus (G′) and loss modulus (G″) showed a higher degree of abrupt increase with the increase of shear stress. The yarn pull-out test showed that the yarn friction of M-MWNT/STF/Kevlar fabrics was far superior to the original fabrics. Importantly, under similar areal density, the M-MWNT/STF/Kevlar fabrics could resist 1261.4 N quasi-static stab force and absorb 41.3 J energy, which were much higher than neat Kevlar fabrics. The results of this research indicated that quasi-static stab resistance was improved by M-MWNTs, which was attributed to the excellent shear-thickening effect and the high yarn friction. Therefore, M-MWNT/STF/Kevlar fabrics have a broad prospect in the fields of body protection.

Single-yarn pull-out test in neat, solvent-treated and shear-thickening fluid-impregnated Kevlar® KM2 fabric

2017 ◽  
Vol 8 (2) ◽  
pp. 154-178 ◽  
Author(s):  
Mica Grujicic ◽  
Jennifer Snipes ◽  
S. Ramaswami
Keyword(s):  
Finite Element ◽  
Shear Thickening ◽  
Lagrangian Formulation ◽  
Body Armor ◽  
Computational Framework ◽  
Shear Thickening Fluid ◽  
Content Type ◽  
Pull Out ◽  
Single Yarn ◽  
Experimental Findings

Purpose In order to help explain experimental findings related to the stabbing- and ballistic-penetration resistance of flexible body-armor, single-yarn pull-out tests, involving specially prepared fabric-type test coupons, are often carried out. The purpose of this paper is to develop a finite-element-based computational framework for the simulation of the single-yarn pull-out test, and applied to the case of Kevlar® KM2 fabric. Design/methodology/approach Three conditions of the fabric are considered: neat, i.e, as-woven; polyethylene glycol (PEG)-infiltrated; and shear-thickening fluid (STF)-infiltrated. Due to differences in the three conditions of the fabric, the computational framework had to utilize three different finite-element formulations: standard Lagrangian formulation for the neat fabric; combined Eulerian-Lagrangian formulation for the PEG-infiltrated fabric (an Eulerian subdomain had to be used to treat the PEG solvent/dispersant); and combined continuum Lagrangian/discrete-particle formulation for the STF-infiltrated fabric (to account for the interactions of the particles suspended in PEG, which give rise to the STF character of the suspension, with the yarns, the particles had to be treated explicitly). Findings The results obtained for the single-yarn pull-out virtual tests are compared with the authors’ experimental counterparts, and a reasonably good agreement is obtained, for all three conditions of the fabric. Originality/value To the authors’ knowledge, the present work represents the first attempt to simulate single-yarn pull-out tests of Kevlar® KM2 fabric.

Performance behavior of pocketed journal bearing employing non-newtonian lubricant

2021 ◽  
Vol 3 (4) ◽  
pp. 045013
Author(s):  
Vivek Bhardwaj
Keyword(s):  
Coefficient Of Friction ◽  
Power Law ◽  
Carrying Capacity ◽  
Shear Thickening ◽  
Numerical Approach ◽  
Load Carrying Capacity ◽  
Shear Thickening Fluid ◽  
Load Carrying ◽  
Power Law Index ◽  
Performance Behavior

Abstract This paper reports the improvement in the performance behaviors of non-Newtonian fluid lubricated journal bearings employing a rectangular pocket. Coefficient of friction and load carrying capacity of pocketed and non-pocketed bearings are reported and discussed. In the numerical approach, non-Newtonian behavior of lubricant is simulated employing the power law model. Various cases of bearings having different axial length to diameter ratios [(L/D) in the range 0.5–2.0] are considered. Lubricants of different rheology viz. pseudoplastic, Newtonian and shear thickening were employed for lubricating the bearings. Rheology of lubricant is controlled by varying the power law index n in the range 0.9–1.1. Based on the investigation, it is found that the pocketed bearing yields significantly reduced coefficient of friction and higher load carrying capacity in comparison to the non-pocketed bearing. Also, the performance of pocketed bearing improves with the increase in the power law index. Best performance of the pocketed bearing is observed for the bearing having L/D value of 0.5 at high eccentricity ratio when lubricated with the shear thickening fluid (n=1.1).

Mechanical behavior of 3D GFRP composite with pure and treated shear thickening fluid matrix subject to quasi-static puncture and shear impact loading

2020 ◽  
Vol 54 (26) ◽  
pp. 3933-3948
Author(s):  
Hossein Hasan-nezhad ◽  
Mojtaba Yazdani ◽  
Mehdi Salami-Kalajahi ◽  
Mohsen Jeddi
Keyword(s):  
Mechanical Behavior ◽  
Impact Test ◽  
Pure Shear ◽  
Shear Thickening ◽  
Experimental Tests ◽  
Velocity Shear ◽  
Nano Particles ◽  
Low Velocity ◽  
Shear Thickening Fluid ◽  
Pull Out

In this study, a new low-velocity shear impact test was introduced to carefully investigate the resistance of 3D E-glass fiber reinforced polymer composites with shear thickening fluid matrix. The shear thickening fluids were prepared by dispersing silica nano-particles in polyethylene glycol. Pure shear thickening fluid was modified by treating the silica surface with (3-Aminopropyl) triethoxysilane. Despite the low-velocity shear impact test, various experimental tests such as yarn pull-out, quasi-static puncture, flexibility and thickness tests were carried out to study the mechanical behavior of the composites. Results revealed the treated shear thickening fluid up to 60 wt% improves the performance of the impregnated samples against the yarn pull-out and puncture tests by 353% and 45%, respectively, and their shear impact resistance by 130% compared to the neat cases without noticeably affecting the fabric flexibility.

Development of Flexible Extremities Protection utilizing Shear Thickening Fluid/Fabric Composites

2012 ◽  
Author(s):  
Mahesh Hosur ◽  
Norman Wagner ◽  
C. T. Sun ◽  
Vijaya Rangari ◽  
Jack Gillespie ◽  
...  
Keyword(s):  
Shear Thickening ◽  
Shear Thickening Fluid ◽  
Fabric Composites

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

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