Effectiveness of Different Shear Thickening Fluids in Reducing Back Face Signature (BFS) of Body Armor Against Bullet Impact

Author(s):  
SANJEEV K. VERMA ◽  
GURSIMRAN KAUR ◽  
IPSITA BISWAS ◽  
DEBARATI BHATACHARJEE
2017 ◽  
Vol 88 (7) ◽  
pp. 812-832 ◽  
Author(s):  
Rajkishore Nayak ◽  
Ian Crouch ◽  
Sinnappoo Kanesalingam ◽  
Jie Ding ◽  
Ping Tan ◽  
...  

Since the invention of small arms ammunition, the human torso has required protection from hand-gun bullets, and today’s civil and military personnel are regularly clad in soft body armor systems to cope with these threats. However, increasingly, the threat spectrum has widened to include a plethora of both edged and pointed weapons. Over the past two decades in particular, this has required development of either specific soft armors to defeat that particular threat, or the development of multi-threat vests that can resist both hand-gun bullets and knife and spike attacks. In this review, we provide more details about the various material combinations that are used to defeat a knife or spike, since these armor materials are a lot different from the conventional aramid fabrics, and numerous, widely-different solutions are being pursued. The penetration mechanisms associated with the various forms of attack—stabbing and slashing—are discussed, as well as the use of new fibers, shear thickening fluids, and nano-materials in developing these body armor systems.


2019 ◽  
Vol 798 ◽  
pp. 331-336
Author(s):  
Natnicha Nuampakdee ◽  
Sujarinee Sinchai ◽  
Chaiwut Gamonpilas

Shear thickening fluids (STF) have attracted much attention in many applications including body armor. In this study, suspensions of silica colloidal particles and polyethylene glycol fluid were prepared at varying volume fractions φ = 0.3 to 0.52 and their rheological behavior was investigated. It was found that the suspensions exhibited a Newtonian behavior for φ < 0.4, whilst a shear thinning followed by a thickening behavior could clearly be observed for φ > 0.4. Furthermore, the critical shear rates for the onset of shear thickening was found to decrease with increasing silica volume fraction but the corresponding critical shear stresses were independent of the volume fraction. To improve the ballistic protective performance, small amount of hard material particles, such as alumina, were added into the silica suspension of φ = 0.5. It was shown that the critical shear rates of the reinforced-STFs decreased with increasing volume fraction and decreasing alumina particle size. However, higher thickening ratio was observed for the alumina additive with agglomerated structure and this ratio increased with increasing alumina volume fraction.


2019 ◽  
Vol 64 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Balasubrahmanya Harish Manukonda ◽  
Victor Avisek Chatterjee ◽  
Sanjeev Kumar Verma ◽  
Debarati Bhattacharjee ◽  
Ipsita Biswas ◽  
...  

The ballistic resistance of high-strength fabrics improves upon impregnation with Shear Thickening Fluids (STFs). The performance of such STF treated fabrics depends on the rheological properties of the STF which in turn are governed by the physicochemical properties of the STF. The present study utilizes rheological characterization of shear thickening silica-polyethylene glycol dispersions (of different material configurations in terms of packing fraction, particle size and continuous phase viscosity) to assess their performance and obtain the best STF material configuration for ballistic body armor applications based on the design criteria proposed herein. The ballistic performance assessment results showed that the STFs with high packing fractions which thicken discontinuously, are highly effective compared to the continuously shear thickening fluids. Furthermore, the use of smaller particle size dispersed phase in the STF formulation was determined to be economical. Also, the use of lower molecular weight dispersion medium was suggested as it allows for a broader working temperature range of the STF. Additionally, the technological issues associated with the development and the practical application of STF-Armor were addressed.


2011 ◽  
Vol 4 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Jie Ding ◽  
Weihua Li ◽  
Shirley Z. Shen

2021 ◽  
pp. 002199832098424
Author(s):  
Mohsen Jeddi ◽  
Mojtaba Yazdani

Whereas most previous studies have focused on improving the penetration resistance of Shear Thickening Fluids (STFs) treated composites, in this study, the dynamic compressive response of single and multi-ply 3 D E-Glass Fiber Reinforced Polymer (GFRP) composites with the STF matrix was investigated by using a drop-weight low-velocity impact test. The experimental results revealed the STF improved the compressive and cushioning performance of the composites such that with increasing its concentration, further improvement was observed. The five-ply composite containing the STF of 30 wt% silica nanoparticles and 1 wt% carbon nanotubes (CNTs) reduced the applied peak force by 56% and 26% compared to a steel plate and five-ply neat samples, respectively. A series of repeated impacts was performed, and it was found that the performance of high-concentration composites is further decreased under this type of loading.


2007 ◽  
Vol 46 (8) ◽  
pp. 1099-1108 ◽  
Author(s):  
Christian Fischer ◽  
Christopher J. G. Plummer ◽  
Véronique Michaud ◽  
Pierre-Etienne Bourban ◽  
Jan-Anders E. Månson

Author(s):  
Nariman Ashrafi ◽  
Habib Karimi Haghighi

The effects of nonlinearities on the stability are explored for shear thickening fluids in the narrow-gap limit of the Taylor-Couette flow. It is assumed that shear-thickening fluids behave exactly as opposite of shear thinning ones. A dynamical system is obtained from the conservation of mass and momentum equations which include nonlinear terms in velocity components due to the shear-dependent viscosity. It is found that the critical Taylor number, corresponding to the loss of stability of Couette flow becomes higher as the shear-thickening effects increases. Similar to the shear thinning case, the Taylor vortex structure emerges in the shear thickening flow, however they quickly disappear thus bringing the flow back to the purely azimuthal flow. Naturally, one expects shear thickening fluids to result in inverse dynamical behavior of shear thinning fluids. This study proves that this is not the case for every point on the bifurcation diagram.


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