Numerical simulation of the impact behaviors of shear thickening fluid impregnated warp-knitted spacer fabric

2015 ◽  
Vol 69 ◽  
pp. 191-200 ◽  
Author(s):  
Zhenqian Lu ◽  
Liwei Wu ◽  
Bohong Gu ◽  
Baozhong Sun
Keyword(s):  
Numerical Simulation ◽  
Shear Thickening ◽  
Shear Thickening Fluid ◽  
Spacer Fabric ◽  
The Impact

Preparation of auxetic warp-knitted spacer fabric impregnated with shear thickening fluid for low-velocity impact resistance

2020 ◽  
pp. 152808372092701 ◽  
Author(s):  
Wanli Xu ◽  
Biao Yan ◽  
Dongmei Hu ◽  
Pibo Ma
Keyword(s):  
Shear Rate ◽  
Energy Absorption ◽  
Impact Resistance ◽  
Shear Thickening ◽  
Weight Fraction ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Shear Thickening Fluid ◽  
Spacer Fabric ◽  
The Impact

This paper reports the preparation of auxetic warp-knitted spacer fabric impregnated with shear thickening fluid and studied its impact behavior under low-velocity impact loading. The shear thickening fluids have been prepared by mechanically dispersing 12 nm silica particles with weight fraction of 10, 15, 20, and 25% in various carriers (PEG200, PEG400, and PEG600). Rheological results indicate that shear thickening fluid experiences shear thickening transition at a specific shear rate. The critical shear rate reduces, and initial viscosity and maximum viscosity increase with the increase of silica weight fraction. The higher molecular weight of polyethylene glycols can lead to lower critical shear rate. The impact process of composite under impact loading can be divided into three stages. The warp-knitted spacer fabric with different negative Poisson’s ratio has a significant effect on the impact behavior. The warp-knitted spacer fabric with better auxetic performance endows composite better impact resistance, the specific performance is the deformation depth, and energy absorption and peak load increase with the increase of auxetic effect of fabric. The silica weight fraction of shear thickening fluid can increase the energy absorption of composite due to the shear thickening transition of shear thickening fluid. Shear thickening fluid has a synergistic effect with the auxetic warp-knitted spacer fabric on impact resistance of composite. The various carriers have no obvious influence on the overall energy absorption and impact load of composites.

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 Functionalization of silica particles to tune the impact resistance of shear thickening fluid treated aramid fabrics

RSC Advances ◽  
2017 ◽  
Vol 7 (78) ◽  
pp. 49787-49794 ◽  
Author(s):  
K. Talreja ◽  
I. Chauhan ◽  
A. Ghosh ◽  
A. Majumdar ◽  
B. S. Butola
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Impact Resistance ◽  
Shear Thickening ◽  
Silica Particles ◽  
Modified Silica ◽  
Shear Thickening Fluid ◽  
Aramid Fabrics ◽  
And Control ◽  
The Impact

Kevlar fabrics treated with MTMS modified silica based STF showed better impact energy absorption as compared to APTES modified and control silica based STF treated fabrics, attributed to changes in interactions between fabrics and silica particles.

Improving the impact resistance of p-aramid fabrics by sequential impregnation with shear thickening fluid

2016 ◽  
Vol 17 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Abhijit Majumdar ◽  
Bhupendra S. Butola ◽  
Ankita Srivastava ◽  
Debarati Bhattacharjee ◽  
Ipsita Biswas ◽  
...  
Keyword(s):  
Impact Resistance ◽  
Shear Thickening ◽  
Shear Thickening Fluid ◽  
Aramid Fabrics ◽  
The Impact

Treated knitted fabric for hip-protective pads for elderly women, part I: force attenuation capacity

2018 ◽  
Vol 89 (8) ◽  
pp. 1408-1416 ◽  
Author(s):  
Wiah Wardiningsih ◽  
Olga Troynikov
Keyword(s):  
Hip Fractures ◽  
Elderly Women ◽  
Shear Thickening ◽  
The Elderly ◽  
Treatment Method ◽  
Shear Thickening Fluid ◽  
Impact Forces ◽  
Closed Cell ◽  
Spacer Fabric ◽  
Spacer Fabrics

This paper describes a study of hip-protective pads made from warp-knitted spacer fabric treated with shear thickening fluid (STF). Hip fractures, mostly caused by falls, are a substantial contributor to morbidity and mortality in the elderly, and incidence is rising worldwide. Hip-protective pads reduce fractures, but wearing adherence is poor. Protective pads made from breathable and comfortable fabrics can improve adherence and prevent more hip fractures. In this research, warp-knitted spacer fabrics were treated with STF using different methods. Treatment 1 involved STF and room-temperature vulcanizing silicone, while treatment 2 applied STF and tetraisopropyl titanate. The effects on force attenuation capacity of each treatment method, the amount of STF used, and fabric layering were measured using drop impact tests. Treated knitted spacer fabric had significantly higher force attenuation capacity than untreated knitted spacer fabric. Impact forces decreased as the number of layers increased and as STF concentrations rose. Treatments 1 and 2 produced fabrics with force attenuation capacity similar to that of closed-cell foam.

scholarly journals Composite Materials Based on Twaron and Nano Materials

2019 ◽  
Vol 9 (1) ◽  
pp. 571-575
Keyword(s):  
Polyethylene Glycol ◽  
Composite Materials ◽  
Indentation Depth ◽  
Shear Thickening ◽  
Rheological Behaviour ◽  
Hot Water ◽  
Nano Materials ◽  
Shear Thickening Fluid ◽  
Gas Gun ◽  
The Impact

This research aims to participate in producing body shield that can overcome pervious drawbacks using behaviour of shear thickening fluid. Initially, the rheological behaviour of silica-polyethylene glycol shear thickening fluid is examined at different concentrations. Then, ballistic fabric samples are impregnated into silica-polyethylene glycol shear thickening fluid at various concentrations of silica and tested using gas gun simulating real ballistic threat. After that, the impact of rubbery hot water pack filled with around 66.67 wt% starch in water is tested using gas gun. Results showed as the concentration of silica increases, the indentation depth in the impregnated fabric decreases which may result in improving performance of ballistic fabric to 12.5 % in case of using 60 wt% silica, 7.35 % in case of using 30 wt% silica and 3.31 % in case of using 7.5 wt% silica with respect to plain sample. As it showed that no indentation depth is formed in modelling clay when rubbery hot water pack filled with around 66.67 wt% starch in water is tested using gas gun causing improvement percentage to be 100% compared to plain sample of Twaron (CT 714).

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