scholarly journals A phenomenological theory-based viscosity model for shear thickening fluids

2021 ◽  
Author(s):  
Kun Lin ◽  
Jiapeng Qi ◽  
Hongjun Liu ◽  
Minghai Wei ◽  
Hua Yi Peng
Keyword(s):  
Experimental Data ◽  
Impact Resistance ◽  
Shear Thickening ◽  
Phenomenological Theory ◽  
Logistic Function ◽  
Viscosity Model ◽  
Model Parameters ◽  
Shear Rates ◽  
Marquardt Algorithm ◽  
Shear Thickening Fluids

Abstract A viscosity model for shear thickening fluids (STFs) based on phenomenological theory is proposed. The model considers three characteristic regions of the typical material properties of STFs: a shear thinning region at low shear rates, followed by a sharp increase in viscosity above the critical shear rate, and subsequently a significant failure region at high shear rates. The typical S-shaped characteristic of the STF viscosity curve is represented using the logistic function, and suitable constraints are applied to satisfy the continuity of the viscosity model. Then, the Levenberg–Marquardt algorithm is introduced to fit the constitutive model parameters based on experimental data. Verification against experimental data shows that the model can predict the viscosity behavior of STF systems composed of different materials with different mass concentrations and temperatures. The proposed viscosity model provides a calculation basis for the engineering applications of STFs (e.g., in increasing impact resistance and reducing vibration).

scholarly journals Designing Shock Absorbing Composites by Impregnating Woven Fabrics with Shear Thickening Fluids

2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Aaditya Saha ◽  
Fred Avett
Keyword(s):  
Impact Resistance ◽  
Shear Thickening ◽  
Force Sensor ◽  
Woven Fabrics ◽  
Polyurethane Foams ◽  
Nano Particle ◽  
Shock Absorption ◽  
Carrier Fluid ◽  
Shear Thickening Fluids ◽  
The Impact

Millions of sports and recreation-related injuries occur each year. Different shock-absorbing solutions, such as polyethylene and polyurethane foams, are used in helmets and protective equipment, but one area most sports-gear manufacturers have not explored is the usage of shear thickening fluids (STFs). An STF is a material that is soft under normal conditions but acts rigid when stressed or pressured. STF composites were fabricated and tested with the goal of exploring their viability for use in shock-absorption applications, especially for sports. The role of fabric- and particle-type, particle-to-carrier fluid ratios, nano-particle additives, and the thickness of the composite were studied, and were all hypothesized to have an effect on the impact-resistance of the fabricated STF-composites. Drop-tests were conducted by releasing a 1.1-lb. weight from an electromagnet onto the composites. An impact-force sensor was placed underneath. The weight and height of the drop were chosen to simulate the hardest recorded NFL hit. All hypothesized factors were found to affect impact resistance. The combination of nylon-fabric impregnated by an STF mix of propylene-glycol and silica-nanoparticles, with a cerium-oxide nano-particle additive, displayed better shock-absorption behavior than other fabricated composites. All of the STF-composites also outperformed tested commercial shock-absorption materials despite being thinner and more flexible. These results demonstrate the potential of using STF-impregnated textile fabrics for protective composites for sportswear, as well as for non-sport shock-absorption applications, like in military vests and helmets, and aerospace applications. Further research is necessary to work towards a final product which can be used.

Two-dimensional (2D) fabrics and three-dimensional (3D) preforms for ballistic and stabbing protection: A review

2016 ◽  
Vol 87 (18) ◽  
pp. 2275-2304 ◽  
Author(s):  
Kadir Bilisik
Keyword(s):  
Impact Resistance ◽  
Three Dimensional ◽  
Shear Thickening ◽  
High Strength ◽  
Computational Techniques ◽  
Two Dimensional ◽  
Shear Thickening Fluids ◽  
Recent Developments ◽  
Ballistic Properties ◽  
The Impact

In this study, the impact resistance of two-dimensional (2D) fabrics and three-dimensional (3D) preforms is explained. These fabrics and preforms include 2D and 3D woven and knitted flat and circular fabrics. Various types of soft/layered structures as well as rigid composite are outlined with some design examples for ballistic and stab threats. The recent developments in nanotubes/nanofibers and shear-thickening fluids (STF) for ballistic fabrics are reviewed. The ballistic properties of single- and multi-layered fabrics are discussed. Their impact mechanism is explained for both soft vest and rigid armor applications. Analytical modeling and computational techniques for the estimation of ballistic properties are outlined. It is concluded that the ballistic/stab properties of fiber-reinforced soft and rigid composites can be enhanced by using high-strength fibers and tough matrices as well as specialized nanomaterials. Ballistic/stab resistance properties were also improved by the development of special fabric architectures. All these design factors are of primary importance for achieving flexible and lightweight ballistic structures with a high ballistic limit.

Incorporation of shear thickening fluid effects into computational modelling of woven fabrics subjected to impact loading: A review

2019 ◽  
Vol 11 (3) ◽  
pp. 340-378 ◽  
Author(s):  
Dakshitha Weerasinghe ◽  
Damith Mohotti ◽  
Jeremy Anderson
Keyword(s):  
Numerical Modelling ◽  
High Performance ◽  
Impact Resistance ◽  
Computational Modelling ◽  
Shear Thickening ◽  
Woven Fabrics ◽  
Shear Thickening Fluid ◽  
Shear Thickening Fluids ◽  
Layered Fabric ◽  
The Impact

Soft armour consisting of multi-layered high-performance fabrics are a popular choice for personal protection. Extensive work done in the last few decades suggests that shear thickening fluids improve the impact resistance of woven fabrics. Shear thickening fluid–impregnated fabrics have been proven as an ideal candidate for producing comfortable, high-performance soft body armour. However, the mechanism of defeating a projectile using a shear thickening fluid–impregnated multi-layered fabric is not fully understood and can be considered as a gap in the research done on the improvement of soft armour. Even though considerable progress has been achieved on dry fabrics, limited studies have been performed on shear thickening fluid–impregnated fabrics. The knowledge of simulation of multi-layered fabric armour is not well developed. The complexity in creating the geometry of the yarns, incorporating friction between yarns and initial pre-tension between yarns due to weaving patterns make the numerical modelling a complex process. In addition, the existing knowledge in this area is widely dispersed in the published literature and requires synthesis to enhance the development of shear thickening fluid–impregnated fabrics. Therefore, this article aims to provide a comprehensive review of the current methods of modelling shear thickening fluid–impregnated fabrics with a critical analysis of the techniques used. The review is preceded by an overview of shear thickening behaviour and related mechanisms, followed by a discussion of innovative approaches in numerical modelling of fabrics. A novel state-of-the-art means of modelling shear thickening fluid–impregnated fabrics is proposed in conclusion of the review of current methods. A short case study is also presented using the proposed approach of modelling.

scholarly journals Novel Approach to The Design of Sound Insulating Composites by Means of a Non-linearly Extrapolated Master Curve

2018 ◽  
Vol 12 (1) ◽  
pp. 14-28
Author(s):  
Cecchini Federico ◽  
Cherubini Valeria ◽  
Francesco Fabbrocino ◽  
Francesca Nanni
Keyword(s):  
Smart Materials ◽  
Composite Structures ◽  
Transmission Loss ◽  
Weight Ratio ◽  
Shear Thickening ◽  
Sound Insulation ◽  
Commercial Vehicles ◽  
Shear Rates ◽  
Novel Approach ◽  
Shear Thickening Fluids

Background:The increasing use of composite structures with a high stiffness-to-weight ratio in commercial vehicles has brought about a reduction in fuel consumption but, on the other hand, has significantly increased noise transmission particularly in case of thin and lightweight structures. Noise is a primary issue for commercial vehicles, such as airplanes, helicopters and cars. The present research deals with the use of smart materials, as Shear-Thickening Fluids (STF, or dilatants) in view of manufacturing elements with increased sound insulation properties.Methods:The response of a sandwich material with the STF core was investigated both experimentally and numerically, by choosing the Sound Transmission Loss (STL) of the composite structure as the figure of merit.The experimental investigation was focused on the manufacturing of a sandwich structure made of metallic skins and a STF core that was successively characterized by sound insertion loss measurement.The numerical investigation was carried out by using a Generalized Transfer Matrix Method (GTMM) and a Statistical Energy Analysis (SEA) in view of selecting the fluid capable of granting the highest acoustic transmission loss.Results:Finally, the test results were compared to the numerical results, showing a noticeable agreement. The used STF showed increasing viscosity at increasing shear rates.

An investigation on composite laminates including shear thickening fluid under stab condition

2018 ◽  
Vol 53 (8) ◽  
pp. 1111-1122 ◽  
Author(s):  
Selim Gürgen
Keyword(s):  
Energy Absorption ◽  
Composite Laminates ◽  
Impact Resistance ◽  
Shear Thickening ◽  
Low Velocity ◽  
Shear Thickening Fluid ◽  
Shear Thickening Fluids ◽  
Absorption Performance ◽  
Thickening Behavior ◽  
The Impact

Shear thickening fluids have been extensively utilized in composite laminate structures to enhance the impact resistance in the last decade. Despite the contribution of shear thickening fluids to the protective systems, the mechanism behind the energy absorption behavior of shear thickening fluids is not fully understood. In the present study, various configurations of composite laminates were prepared and these structures were investigated under low velocity stab conditions. Contrary to the common idea of shear thickening fluid impregnation for fabrics, shear thickening fluids were used in bulk form and by means of this, pure contribution of shear thickening behavior to the energy absorption was investigated. To hold the bulk shear thickening fluids in the composite laminates, Lantor Soric SF honeycomb layers were filled with shear thickening fluids and Twaron fabrics were plied in the structures as the reinforcement. As a result of this study, it is stated that shear thickening behavior is insufficient to effectively improve the energy absorption performance of composite laminates; however, shear thickening fluids are beneficial to fabric based composites because the inter-yarn friction of fabrics is enhanced using shear thickening fluids as an impregnation agent rather than a bulk form.

Effect of Alumina Addition on the Rheological Behavior of Shear Thickening Fluids

2019 ◽  
Vol 798 ◽  
pp. 331-336
Author(s):  
Natnicha Nuampakdee ◽  
Sujarinee Sinchai ◽  
Chaiwut Gamonpilas
Keyword(s):  
Rheological Behavior ◽  
Colloidal Particles ◽  
Volume Fraction ◽  
Shear Thickening ◽  
Body Armor ◽  
Shear Stresses ◽  
Hard Material ◽  
Shear Rates ◽  
Shear Thickening Fluids ◽  
Alumina Addition

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.

Experimental analysis of the impact protection properties for Kevlar® fabrics under different orientation layers and non-Newtonian fluid compositions

2020 ◽  
Vol 54 (24) ◽  
pp. 3515-3526
Author(s):  
Thiago F Santos ◽  
Caroliny M Santos ◽  
Rubens T Fonseca ◽  
Kátia M Melo ◽  
Marcos S Aquino ◽  
...  
Keyword(s):  
Colloidal Silica ◽  
Standard Sample ◽  
Impact Resistance ◽  
Shear Thickening ◽  
Spreading Rate ◽  
Residual Energy ◽  
Avant Garde ◽  
Shear Thickening Fluids ◽  
The Impact ◽  
Silica Suspensions

Use of colloidal silica suspensions impregnated in Kevlar® fabrics is new avant-garde of protection equipment for stab wounds and piercing objects. Kevlar® fabrics impregnated with non-Newtonian fluids have been used for protection against sharp blows, mainly due to their lightweight, good flexibility, and superior resistance properties. The aims of this investigation are to demonstrate that Kevlar® fabric impregnated with shear thickening fluids could be improved its performance through the use Aminopropyltrimethoxysilane, as well as by increasing the concentration of silica nanoparticles in its composition. Friction tests on yarns showed that Kevlar® yarns with shear thickening fluids (sample C3—25% Silica and 75%polyethylene glycol with 38% aminopropyltrimethoxysilane), presented higher strength values (10.5 N) when compared with other samples. Impact resistance tests showed that Kevlar® samples with highest concentration shear thickening fluids nanoparticles and oriented fabric layers (C3 OR) presented better performance regarding to penetration depth of stabs P1 (17 mm), S1 (18 mm) and as well as residual energy dissipation, when compared with the standard and other samples. Addition of shear thickening fluids cause reduction in the flexibility of the Kevlar® fabrics, producing sample with 42.74% less flexibility than the standard sample (C3). Adhesion tests for C3 samples exhibited more stable wettability and spreading rate, i.e., a greater adhesion of shear thickening fluids in Kevlar® fabrics than other samples due to its composition (higher concentration of nanoparticles and superior amount of silane agent). Finally, results showed that the shear thickening fluids composition as well as Kevlar® layers orientation should be used to improve the performance of Kevlar® fabrics under impact tests.

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