scholarly journals Validity of Amontons’ law for run-in short-cut aramid fiber reinforced elastomers: The effect of epoxy coated fibers

Friction ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 613-625
Author(s):  
M. Khafidh ◽  
D. J. Schipper ◽  
M. A. Masen ◽  
N. Vleugels ◽  
W. K. Dierkes ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Normal Force ◽  
Threshold Value ◽  
Aramid Fiber ◽  
Fiber Reinforced ◽  
Aramid Fibers ◽  
Frictional Behavior ◽  
Pin On Disc ◽  
Counter Surface ◽  
Reinforcing Filler

Abstract Friction between two contacting surfaces is studied extensively. One of the known friction theories is Amontons’ law which states that the friction force is proportional to the normal force. However, Amontons’ law has been found to be invalid for elastomers. In the present study, the validity of Amontons’ law for short-cut aramid fiber reinforced elastomers is studied. Two types of fillers are used to reinforce the elastomers, namely highly dispersible silica and short-cut aramid fibers. Short-cut aramid fibers with two different surface treatments are used, namely non-reactive fibers with standard oily finish (SF-fibers) and fibers treated with an epoxy coating (EF-fibers). A pin-on-disc tribometer is used to investigate the frictional behavior of the composites in sliding contact with a granite counter surface. The results show that, after the run-in phase, Amontons’ law is valid for those composites that are reinforced by short-cut aramid fibers (without reinforcing filler, i.e., silica) if the contact pressure is below a threshold value. However, once the contact pressure exceeds this threshold value, Amontons’ law will be invalid. The threshold contact pressure of the composites containing EF-fibers is higher than of the composites containing SF-fibers. The composites that are reinforced by silica and short-cut aramid fibers do not follow Amontons’ law.

The Wear of Aramid Fiber Reinforced Brake Pads: The Role of Aramid Fibers

1994 ◽  
Vol 37 (3) ◽  
pp. 559-565 ◽  
Author(s):  
Takahisa Kato ◽  
Akira Magario
Keyword(s):  
Aramid Fiber ◽  
Fiber Reinforced ◽  
Aramid Fibers ◽  
Brake Pads

scholarly journals Strength and Durability Study of Concrete Structures Using Aramid-Fiber-Reinforced Polymer

Fibers ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 11 ◽  
Author(s):  
Rajashekhar Talikoti ◽  
Sachin Kandekar
Keyword(s):  
Weight Loss ◽  
Compressive Strength ◽  
Concrete Structures ◽  
Aramid Fiber ◽  
Fiber Reinforced Polymer ◽  
Structural Elements ◽  
Fiber Reinforced ◽  
Aramid Fibers ◽  
Reinforced Polymer ◽  
Concrete Cube

Fiber-reinforced polymer (FRP) is an important material used for strengthening and retrofitting of reinforced concrete structures. Commonly used fibers are glass, carbon, and aramid fibers. The durability of structures can be extended by selecting an appropriate method of strengthening. FRP wrapping is one of the easiest methods for repair, retrofit, and maintenance of structural elements. Deterioration of structures may be due to moisture content, salt water, or contact with alkali solutions. Using FRP, additional strength can be gained by structural elements. This paper investigates the durability of aramid-fiber-wrapped concrete cube specimens subjected to acid attack and temperature rise. The study focuses on the durability of aramid-fiber-wrapped concrete by considering the compressive strength parameter of the concrete cube. Concrete cubes are prepared as specimens with a double wrapping of aramid fibers. Diluted hydrochloric acid solution is used for immersion of specimens for curing periods of 7, 30, and 70 days. The aramid-fiber wrapping reduces weight loss by 40% and improves compressive strength by 140%. In a fire resistance test, the specimens were kept in a hot air oven at a temperature of 200 °C at different time intervals. Even after fire attack, weight loss in specimens reduced by 60%, with about 150% enhancement in compressive strength due to aramid fiber.

Performance of Modified Aramid Fiber Reinforced Phenolic Foam

2012 ◽  
Vol 557-559 ◽  
pp. 258-261 ◽  
Author(s):  
Huan Yang Yu ◽  
Li Yan Wang ◽  
Guang Qing Gai
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Oxygen Index ◽  
Compressive Modulus ◽  
Aramid Fiber ◽  
Fiber Reinforced ◽  
Aramid Fibers ◽  
Compression Behavior ◽  
Phenolic Foam ◽  
Before And After

A chemical modification was adopted to treat the surface of aramid fibers.The influences of aramid fibers on the friability and compression behavior of phenolic foam before and after modification were studied.Compared with unmodified aramid fiber-reinforced phenolic foam ,foam reinforced with modified aramid fibers exhibits significantly lower friability, higher compressive strength and compressive modulus. The thermal conductivity and Oxygen index of modified aramid fiber- reinforced phenolic foam hasn’t obviously been changed compared with the unmodified counterpart.

Mechanical Properties and Dynamic Mechanical Behavior for Long Aramid Fiber Reinforced Impact Polypropylene Copolymer

2012 ◽  
Vol 591-593 ◽  
pp. 1079-1082 ◽  
Author(s):  
Hao Tan ◽  
Hong Sheng Tan ◽  
Xin Lei Tang ◽  
Yan Gang Wang ◽  
Li Ping Li
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Aramid Fiber ◽  
Fiber Reinforced ◽  
Aramid Fibers ◽  
Dynamic Mechanical ◽  
Composite Deformation ◽  
Dynamic Mechanical Behavior ◽  
Single Screw Extruder ◽  
Impact Polypropylene Copolymer

Composites of continuous aramid fiber reinforced impact polypropylene copolymer (IPC) were prepared using a cross-head impregnation mold by self-design fixed on a single screw extruder, and pelleted by a pelleter for injection molding to prepare testing specimens. The mechanical properties of long aramid fibers reinforced impact polypropylene copolymer (IPC) composites were studied. Micrographs of fracture surface of tensile specimens and dynamic mechanical behavior for the composites were analyzed by scanning electron microscope (SEM) and dynamic mechanical analyzer (DMA). The results of experiments show that, the tensile and flexural strengths increased obviously with the aramid fibers content in the composites. SEM results show the compatibility between the aramid fiber and matrix is very poor. The results of the dynamic mechanical behavior of long aramid fibers reinforced IPC composites show that the composite deformation resistance and glass transition temperature increased evidently with the addition of aramid fibers.

Promising Hybrid Fabrics Based on Carbon and Aramid Fibers as a Reinforcing Filler for Polymer Composites

2020 ◽  
Vol 11 (6) ◽  
pp. 1390-1396
Author(s):  
G. F. Zhelezina ◽  
V. G. Bova ◽  
S. I. Voinov ◽  
A. Ch. Kan
Keyword(s):  
Polymer Composites ◽  
Aramid Fibers ◽  
Reinforcing Filler

Sulfone-functionalized poly(p-phenylene terephthalamide) copolymer fibers with improved interfacial adhesion to epoxy matrices

2021 ◽  
pp. 095400832110089
Author(s):  
Ting Li ◽  
Zengxiao Wang ◽  
Hao Zhang ◽  
Yutong Cao ◽  
Zuming Hu ◽  
...  
Keyword(s):  
Interfacial Adhesion ◽  
Interfacial Shear Strength ◽  
Aramid Fiber ◽  
Fiber Reinforced Composites ◽  
Epoxy Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Regular Arrangement ◽  
Epoxy Matrices ◽  
Polymerization Conditions

The poor interfacial adhesion of aramid fiber and matrix limits the application of the final composites. In this study, a series of the sulfone-functionalized poly( p-phenylene terephthalamide) (SPPTA) copolymers were satisfactorily synthesized and the effects of polymerization conditions (contents of the additional monomer and the cosolvent LiCl, molar concentration and ratio of the monomer, reaction temperature and time) on the molecular weight of the copolymer were discussed. The introduction of the sulfone group in aromatic polyamides not only increased the polarity of poly( p-phenylene terephthalamide) (PPTA) but destroyed the regular arrangement of the molecular chains, which greatly improved the surface free energy and the solubility of the polymers in organic solvents. The polymer maintained excellent thermal and interfacial properties. Compared with the PPTA fiber/epoxy composites, the interfacial shear strength (IFSS) of SPPTA fiber-reinforced epoxy composites reached 43.5 MPa, with a significantly enhancement of 20.8%, implying that the study provided an effective method to achieve highly interfacial adhesion of aramid fiber-reinforced composites.

scholarly journals Modeling of Bridging Law for Bundled Aramid Fiber-Reinforced Cementitious Composite and its Adaptability in Crack Width Evaluation

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 179
Author(s):  
Daiki Sunaga ◽  
Takumi Koba ◽  
Toshiyuki Kanakubo
Keyword(s):  
Fiber Orientation ◽  
Crack Width ◽  
Volume Fraction ◽  
Characteristic Point ◽  
Crack Opening ◽  
Aramid Fiber ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Cross Sectional ◽  
Bridging Law

Tensile performance of fiber-reinforced cementitious composite (FRCC) after first cracking is characterized by fiber-bridging stress–crack width relationships called bridging law. The bridging law can be calculated by an integral calculus of forces carried by individual fibers, considering the fiber orientation. The objective of this study was to propose a simplified model of bridging law for bundled aramid fiber, considering fiber orientation for the practical use. By using the pullout characteristic of bundled aramid fiber obtained in the previous study, the bridging laws were calculated for various cases of fiber orientation. The calculated results were expressed by a bilinear model, and each characteristic point is expressed by the function of fiber-orientation intensity. After that, uniaxial tension tests of steel reinforced aramid-FRCC prism specimens were conducted to obtain the crack-opening behavior and confirm the adaptability of the modeled bridging laws in crack-width evaluation. The experimental parameters are cross-sectional dimensions of specimens and volume fraction of fiber. The test results are compared with the theoretical curves calculated by using the modeled bridging law and show good agreements in each parameter.

Wear characterization of basalt fiber reinforced polypropylene/polylactic acid hybrid polymer composite

2021 ◽  
pp. 135065012110300
Author(s):  
Arputham Arul Jeya Kumar ◽  
Muniyandi Prakash ◽  
Abburi Lakshmankumar ◽  
Kesuboyina Haswanth
Keyword(s):  
Polylactic Acid ◽  
Polymer Composite ◽  
Basalt Fiber ◽  
Weight Fraction ◽  
The Other ◽  
Wear Loss ◽  
Specimen Preparation ◽  
Fiber Reinforced ◽  
Pin On Disc ◽  
Hybrid Polymer Composite

In this work, the wear loss of basalt fiber reinforced polypropylene/polylactic acid polymer composite was analyzed using pin-on-disc under dry sliding conditions. The polypropylene, polylactic acid, and basalt fiber (chopped fiber) are melted and mixed homogeneously using a twin-screw extruder, which is followed by an injection molding technique for specimen preparation. The specimens are named as PPB1 (polypropylene, 50%; polylactic acid, 35%; basalt fiber, 15%), PPB2 (polypropylene, 55%; polylactic acid, 30%; basalt fiber, 15%), and PPB3 (polypropylene, 60%; polylactic acid, 25%; basalt fiber, 15%) based on their weight fraction. The wear rate and coefficient of friction are measured for each sample subjected to three different loads and sliding velocities. It is observed from the wear mapping that the wear loss of sample PPB3 is relatively less when compared with the other samples. The scanning electron microscope images of the worn-out region of the sample reveal the fracture and dislocation of fibers in the matrix. The sample PPB3 shows low wear loss. It is due to the better cohesion between the fiber and the matrixes when compared with the other samples.

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