Dynamic Properties of Human Hair Fiber–Reinforced Yamuna Sand

2019 ◽  
Vol 48 (6) ◽  
pp. 20180133 ◽  
Author(s):  
Raghvendra Sahu ◽  
B. Janaki Ramaiah ◽  
Ramanathan Ayothiraman ◽  
G. V. Ramana
Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2476
Author(s):  
Haiwen Li ◽  
Sathwik S. Kasyap ◽  
Kostas Senetakis

The use of polypropylene fibers as a geosynthetic in infrastructures is a promising ground treatment method with applications in the enhancement of the bearing capacity of foundations, slope rehabilitation, strengthening of backfills, as well as the improvement of the seismic behavior of geo-systems. Despite the large number of studies published in the literature investigating the properties of fiber-reinforced soils, less attention has been given in the evaluation of the dynamic properties of these composites, especially in examining damping characteristics and the influence of fiber inclusion and content. In the present study, the effect of polypropylene fiber inclusion on the small-strain damping ratio of sands with different gradations and various particle shapes was investigated through resonant column (macroscopic) experiments. The macroscopic test results suggested that the damping ratio of the mixtures tended to increase with increasing fiber content. Accordingly, a new expression was proposed which considers the influence of fiber content in the estimation of the small-strain damping of polypropylene fiber-sand mixtures and it can be complementary of damping modeling from small-to-medium strains based on previously developed expressions in the regime of medium strains. Additional insights were attempted to be obtained on the energy dissipation and contribution of fibers of these composite materials by performing grain-scale tests which further supported the macroscopic experimental test results. It was also attempted to interpret, based on the grain-scale tests results, the influence of fiber inclusion in a wide spectrum of properties for fiber-reinforced sands providing some general inferences on the contribution of polypropylene fibers on the constitutive behavior of granular materials.


2018 ◽  
Vol 55 (5) ◽  
pp. 317-324 ◽  
Author(s):  
Lei Gao ◽  
Guohui Hu ◽  
Jiaru Chen ◽  
Keyi Ren ◽  
Qiuyue Zhou ◽  
...  

2020 ◽  
Vol 5 (6) ◽  
pp. 702-707
Author(s):  
Fariborz M. Tehrani ◽  
Nazmieh A. Masswadi ◽  
Nathan M. Miller ◽  
Arezoo Sadrinezhad

This paper presents the results of an experimental study to investigate dynamic properties of polypropylene fiber-reinforced concrete beams with lightweight expanded shale (ES) and tire-derived aggregates (TDA). The mixture design followed past experiences in combining ES and TDA to enhance toughness and energy absorption in flexural behavior. The new mixture also contained 2% fiber by volume to improve such properties further. Experiments included compressive testing on cylindrical specimens as well as flexural testing on rectangular specimens to verify mechanical properties of fiber-reinforced tire-derived lightweight aggregate concrete (FRTDLWAC) subject to static loading. The results of these experiments confirmed reduction of mechanical strength due to addition of TDA and improvements in flexural strength due to fiber reinforcement. The dynamic testing included non-destructive impact loads applied to flexural specimens using a standard Schmidt hammer. A high-speed camera recorded the response of the system at 200 frames per second to allow detailed observations and measurements. Interpretation of energy-based dynamic results revealed that TDA enhances energy absorption through damping in flexural behavior. Results also indicated that fiber reinforcement reduces the amount of absorbed dynamic energy, even though; it enhances the absorbed strain energy due to crack bridging effect.


2019 ◽  
Vol 45 (2) ◽  
pp. 1017-1033 ◽  
Author(s):  
Mehmet Bulut ◽  
Ömer Yavuz Bozkurt ◽  
Ahmet Erkliğ ◽  
Hakan Yaykaşlı ◽  
Özkan Özbek

2017 ◽  
Vol 36 (23) ◽  
pp. 1745-1755 ◽  
Author(s):  
Tsung-Han Hsieh ◽  
Yau-Shian Huang ◽  
Ming-Yuan Shen

Carbon aerogels are a promising candidate for vibration insulation due to their three-dimensional networked structures interconnected with carbon nanoparticles. However, the effect of adding carbon aerogels to polymer-based composites on their dynamic properties remains unclear. In this study, an epoxy polymer matrix was modified with carbon aerogels, and this modified matrix was used to manufacture nanocomposite plates and carbon fiber-reinforced polymer composite laminates to investigate its dynamic properties. Force vibration tests were performed on cantilever beams of the composite beams. The frequency responses of the composite beams were measured experimentally and analytically; the half-power method was used to calculate the damping ratio for each vibration mode. According to the experimental results, the presence of carbon aerogel in the nanocomposites and laminates steadily increased the natural frequencies. Differences within 10% of the natural frequencies were obtained between the experimental and numerically. Furthermore, the damping ratios of the nanocomposite and laminate beams increased significantly with the increase in aerogel loading. For a nanocomposite with 0.3 wt% aerogel, a damping ratio approximately 44% greater than that of unmodified nanocomposite was obtained. The maximum damping ratio was 4.682% for the laminate with 0.5 wt% aerogel—an 88% increase compared with the unmodified laminate.


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