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.

Implementing the Split-Hopkinson Pressure Bar Technique for Shear Thickening Fluid Evaluation

2008 ◽  
Author(s):  
Amanda S. Lim ◽  
Sergey L. Lopatnikov ◽  
John W. Gillespie ◽  
Albert Co ◽  
Gary L. Leal ◽  
...  
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Shear Thickening ◽  
Hopkinson Pressure Bar ◽  
Shear Thickening Fluid ◽  
Split Hopkinson ◽  
Pressure Bar

Mechanical properties of composites made of hybrid fabric impregnated with silica nanoparticles and epoxy resin

2017 ◽  
Vol 31 (26) ◽  
pp. 1750235
Author(s):  
N. Kordani ◽  
M. Alizadeh ◽  
F. Lohrasby ◽  
R. Khajavi ◽  
H. R. Baharvandi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Natural Fibers ◽  
Shear Thickening ◽  
Silica Particles ◽  
Nano Silica ◽  
Shear Thickening Fluid ◽  
Synthetic Fibers ◽  
Hybrid Fabric ◽  
Properties Of Composites

In this study, the mechanical properties of composites will be examined which were made from Kenaf and hybrid fabric with a simple structure that was coated with epoxy resin and nano silica particles. This fabric cotton has a different situation in terms of yarn score and the type of fiber that is used in textiles. Nano silica particles of 200 nm, polyethylene glycol with 200 molecular weights and ethanol with mechanical weight molecular with ratio of 6:1 will be mixed. Suspension of 60% was chosen according to the silica particles. The D6264 standard test for concentrated force was carried out through the cone edge to determine the strength of each of the samples. Increasing of resistance against penetration in the Kenaf samples from the raw until impregnated with the shear thickening fluid is less than the hybrid samples. Slippage of the fibers with the change of round edge indenter to cone edge indenter has changed. Penetration by cone edge to the cloth is done with lower force and it shows the effect of slippage of fibers on the resistance of the penetration. Samples impregnated with the shear thickening fluid in comparison with epoxy resin have lower resistance. Slippage of natural fibers in comparison with synthetic fibers is lower and on the other hand the average of friction between fibers in the natural fibers is more than synthetic fibers.

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.

PREPARATION AND PROPERTIES OF HNT–SiO2COMPOUNDED SHEAR THICKENING FLUID

NANO ◽  
2014 ◽  
Vol 09 (08) ◽  
pp. 1450100 ◽  
Author(s):  
YAN WANG ◽  
YAOFENG ZHU ◽  
YAQIN FU
Keyword(s):  
Electron Microscopy ◽  
Dispersion Medium ◽  
High Speed ◽  
Shear Thickening ◽  
Halloysite Nanotube ◽  
Shear Thickening Fluid ◽  
Transmission Electron ◽  
Polyethylene Glycol 200 ◽  
Dispersed Phases ◽  
Scanning Electron

A novel shear thickening fluid (STF) obtained from a halloysite nanotube (HNT) and SiO2compounded system was successfully prepared using HNT and nano- SiO2as dispersed phases and polyethylene glycol 200 (PEG200) as the dispersion medium. The steady rheological behavior of the STF was investigated using a high-speed rotational rheometer, and the dispersion states of SiO2and HNT in PEG200 were characterized by field emission scanning electron microscopy and transmission electron microscopy. Results show that HNT and SiO2coexisted in the compounded system, and presented a special state that was both uniformly dispersed and partially enriched. The shear thickening effect of the STF was significantly enhanced by the enrichment of SiO2loaded on the surface of HNTs in the compounded system.

Study of Dynamic Mechanical Properties on Cement Asphalt Mortar of High Elastic Type

2014 ◽  
Vol 1049-1050 ◽  
pp. 346-353
Author(s):  
Lei Fang ◽  
De Hua Deng ◽  
Jian Wei Peng ◽  
Yong Wang ◽  
Qing Tian
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Mechanical Properties ◽  
Experimental Result ◽  
Dynamic Mechanical ◽  
Ca Mortar ◽  
Asphalt Mortar

Dynamic mechanical properties of high elastic type cement and asphalt mortar (CA mortar) for high-speed railway was studied by split Hopkinson pressure bar (SHPB) in this paper. The experimental result show that the compressive strength of CA mortar increases gradually with the increasing of strain-rate. However, the increasing rate of compressive of CA mortar decreases with the further increasing strain-rate. The increasing rate of compressive strength is 57.65% for the strain-rate ranging from 25.16 s-1to 35.79 s-1 and 20.39% for the strain-rate from 94.64 up to 111.15 s-1, respectively. The larger the strain-rate is, the more serious the cracking is when CA mortar specimen damaged. The specific energy adsorption of CA mortar increases with the increasing strain-rate.

Self-Sealing Pneumatic Pressure Vessel With Passive and Active Methods

2011 ◽  
Author(s):  
David A. Hurley ◽  
Dryver R. Huston
Keyword(s):  
Pressure Vessel ◽  
Damage Assessment ◽  
High Speed ◽  
Shear Thickening ◽  
Pressure Vessels ◽  
Test Bed ◽  
Shear Thickening Fluid ◽  
Large Pressure ◽  
Network Pattern ◽  
Practical Constraints

This paper discusses passive and active self-sealing techniques for pressure vessels. The history and state-of-the-art of self-sealing fluid containment vessels is followed by a discussion of challenges specific to implementing self-sealing on pressure vessels. These challenges include large pressure differentials, high speed flows through the leak, the need for relatively rapid response, and embedding the sealing techniques as a composite within a pressure vessel while satisfying practical constraints of weight and size. A benchtop pneumatic test bed provides a setting for evaluating self-sealing technologies. Testing focuses on experiments and models of passive techniques that use shear-thickening fluid coagulation for plugging. This is followed by results that demonstrate the use of active sealing methods with coordinated leak sensing and activated sealing. Acoustic emission (AE) monitoring detects the leak. Electrocoagulation and thermoplastic flow provide the means of controlled sealing. A separate study explores AE testing as a tool for damage assessment. Combining AE testing with neural-network pattern recognition algorithms enables leak detection, location, and size assessment.

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