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

2018 ◽  
Vol 53 (8) ◽  
pp. 1111-1122 ◽  
Author(s):  
Selim Gürgen

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.

RSC Advances ◽  
2017 ◽  
Vol 7 (78) ◽  
pp. 49787-49794 ◽  
Author(s):  
K. Talreja ◽  
I. Chauhan ◽  
A. Ghosh ◽  
A. Majumdar ◽  
B. S. Butola

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.


2020 ◽  
pp. 152808372092701 ◽  
Author(s):  
Wanli Xu ◽  
Biao Yan ◽  
Dongmei Hu ◽  
Pibo Ma

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.


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.


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.


2018 ◽  
Vol 183 ◽  
pp. 01044
Author(s):  
Djalel Eddine Tria ◽  
Larbi Hemmouche ◽  
Abdelhadi Allal ◽  
Abdelkader Benouali

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.


2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Aaditya Saha ◽  
Fred Avett

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.


2016 ◽  
Vol 87 (18) ◽  
pp. 2275-2304 ◽  
Author(s):  
Kadir Bilisik

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.


2016 ◽  
Vol 17 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Abhijit Majumdar ◽  
Bhupendra S. Butola ◽  
Ankita Srivastava ◽  
Debarati Bhattacharjee ◽  
Ipsita Biswas ◽  
...  

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