An Electromechanical In Situ Viscosity Measurement Technique for Shear Thickening Fluids

2021 ◽  
Vol 43 ◽  
pp. 33-43
Author(s):  
Gökhan Haydarlar ◽  
Mehmet Alper Sofuoğlu ◽  
Selim Gürgen ◽  
Melih Cemal Kushan ◽  
Mesut Tekkalmaz

This paper presents the feasibility of developing an electromechanical in-situ viscosity measurement technique by analyzing the detectability of small variations in the viscosity of different shear thickening fluids and their different compositions. Shear thickening fluid (STF) is a kind of non-Newtonian fluid showing an increasing viscosity profile under loading. STF is utilized in several applications to take advantage of its tunable rheology. However, process control in different STF applications requires rheological measurements, which cause a costly investment and long-lasting labor. Therefore, one of the most commonly used in-situ structural health monitoring techniques, electromechanical impedance (EMI), was used in this study. In order to actuate the medium electromechanically, a piezoelectric wafer active sensor (PWAS) was used. The variations in the spectral response of PWAS resonator that can be submerged into shear thickening fluid are analyzed by the root mean square deviation, mean absolute percentage deviation and correlation coefficient deviation. According to the results, EMI metrics provide good correlations with the rheological parameters of STF and thereby enabling quick and low-cost rheological control for STF applications such as vibration dampers or stiffness control systems.

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.


2012 ◽  
Vol 701 ◽  
pp. 201-227 ◽  
Author(s):  
Iman Lashgari ◽  
Jan O. Pralits ◽  
Flavio Giannetti ◽  
Luca Brandt

AbstractThe first bifurcation and the instability mechanisms of shear-thinning and shear-thickening fluids flowing past a circular cylinder are studied using linear theory and numerical simulations. Structural sensitivity analysis based on the idea of a ‘wavemaker’ is performed to identify the core of the instability. The shear-dependent viscosity is modelled by the Carreau model where the rheological parameters, i.e. the power-index and the material time constant, are chosen in the range $0. 4\leq n\leq 1. 75$ and $0. 1\leq \lambda \leq 100$. We show how shear-thinning/shear-thickening effects destabilize/stabilize the flow dramatically when scaling the problem with the reference zero-shear-rate viscosity. These variations are explained by modifications of the steady base flow due to the shear-dependent viscosity; the instability mechanisms are only slightly changed. The characteristics of the base flow, drag coefficient and size of recirculation bubble are presented to assess shear-thinning effects. We demonstrate that at critical conditions the local Reynolds number in the core of the instability is around 50 as for Newtonian fluids. The perturbation kinetic energy budget is also considered to examine the physical mechanism of the instability.


2018 ◽  
Vol 49 (10) ◽  
pp. 1317-1333 ◽  
Author(s):  
Lijuan Wang ◽  
Kejing Yu ◽  
Diantang Zhang ◽  
Kun Qian

This paper mainly investigated the cut resistant property of shear thickening fluid enhanced organic high-performance yarn. Cut tests of neat yarn and shear thickening fluids/yarn were performed with two cutting angles. External forces involved in the cutting were analyzed. A simple theoretical relation was established based on the principle of the energy conversion. Two types of shear thickening fluids were prepared. Compared to neat yarn, the shear thickening fluids/yarn exhibited extremely high cut resistant property, especially, shear thickening fluids/yarn with graphene, indicating a synergistic effect. Fracture surfaces of fibers after yarns cut off were initially studied, which verified the cut resistant characteristics of organic high-performance yarns and shear thickening fluids/yarn.


2014 ◽  
Vol 33 (22) ◽  
pp. 2064-2072 ◽  
Author(s):  
Hamid Reza Baharvandi ◽  
Peiman Khaksari ◽  
Morteza Alebouyeh ◽  
Masoud Alizadeh ◽  
Jalal Khojasteh ◽  
...  

The effect of impregnating p-aramid fabrics with shear thickening fluids on their quasi-static puncture resistance performance has been investigated. To prepare the shear thickening fluid, 12 and 60-nm silica particles have been dispersed in polyethylene glycol by means of mechanical mixing. The results of rheological tests indicate that the reduction of particle size leads to the increase of suspension viscosity, increase of critical shear rate, and the diminishing of the frequency of transition to elastic state for the shear thickening fluids. Samples of p-aramid impregnated fabrics were subjected to the quasi-static puncture resistance test according to the American Society for Testing and Materials standard D6264. The quasi-static puncture resistance increased 4.5 times for samples with 35 wt% silica concentration relative to the neat sample. In particular, with the reduction of particle size, the samples undergo less deformation and can withstand larger loads at each shear thickening fluid concentration. However, at low and medium concentrations (15 and 25 wt%), the reduction in the particle size has a large effect on the load-bearing capacity of the fabrics. But in the case of 35 wt% concentration for both the 12- and 60-nm particles, the difference between maximum loads withstood by the fabric is negligible.


2018 ◽  
Vol 8 ◽  
pp. 184798041878655 ◽  
Author(s):  
Minghai Wei ◽  
Li Sun ◽  
Peipei Qi ◽  
Chunguang Chang ◽  
Chunyang Zhu

In general, shear thickening fluids show a marked increase in viscosity beyond a critical shear rate, which can be attributed to the hydrodynamic clustering effects, where in any external energy acting on a shear thickening fluid is dissipated quickly. However, there is a lack of theoretical modeling to predict the viscosity curve of shear thickening fluids, which changes continuously with the increasing shear rate. In this article, a phenomenological continuous viscosity modeling for a class of shear thickening fluids is proposed. The modeling predicts shear thickening and thinning behaviors that are naturally exhibited by shear thickening fluids for high and high enough values of the shear rate. The result shows that the phenomenological modeling provides a very good fit for several independent experimental data sets. Therefore, the proposed modeling can be used in numerical simulations and theoretical analysis across different engineering fields.


2019 ◽  
Vol 11 (3) ◽  
pp. 340-378 ◽  
Author(s):  
Dakshitha Weerasinghe ◽  
Damith Mohotti ◽  
Jeremy Anderson

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.


2015 ◽  
Vol 782 ◽  
pp. 153-157 ◽  
Author(s):  
Yan Wang ◽  
Shu Kui Li ◽  
Xin Ya Feng

This study investigates the ballistic penetration performance of aramid fabric impregnated with shear thickening fluid. The ballistic test was conducted at impact velocity of 445 m/s, and three types of shear thickening fluids prepared with silica particles of different sizes (200nm, 340nm and 480nm) are involved. The results demonstrate an enhancement in ballistic properties of fabric due to the impregnation of shear thickening fluids. The fabrics with smaller particle size show better ballistic performance. Microscopic observation of aramid fabric reveals that shear thickening fluids with smaller silica particles have a better adhesion on and between yarns, enhancinging the coupling effect between yarns. The corresponding mechanism was discussed in the paper.


2021 ◽  
Author(s):  
Jakub Mikolaj Szczepanski

Great interest has aroused in developing the next generation body armour based on the incorporation of a Shear Thickening Fluid (STF) into high performance fabrics (Kevlar®, UHMWPE). This innovative technoloy allows for the production of comfortable, flexible, lightweight, stab and ballistic resistant protective garments. This innovative technology allows for the production of comfortable, flexible, lightweight, stab and ballistic resistant protective garments. The furrent research was undertaken to evaluate the stab resistance and the chemical properties of types of high performance fabrics, Kevlar and Ultra Hight Molecular Weight Polyethylene (UHMWPE), impregnated with several types of shear thickening fluids. The stab resistance properties of all samples were tested using drop tower and quasistatic testing apparatuses. Chemical compositions and microscopic structures were analyzed with Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Energy Dispersive Spectroscopy. The current study demonstrated the importance of incorporating Shear Thickening Fluid into woven high performance fibres. The results clearly display a significant enhancement in puncture resistance ony of Kevlar® fabrics impregnated with different combination of STFs.


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