scholarly journals Effect of Process Parameters of CNT Containing Friction Powder on Flexural Properties and Friction Performance of Organic Brake Friction Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Kuo-Jung Lee ◽  
Mao-Hsiang Hsu ◽  
Huy-Zu Cheng
Keyword(s):  
Weight Loss ◽  
Carbon Nanotube ◽  
Friction Coefficient ◽  
Flexural Strength ◽  
Process Parameters ◽  
Carbon Clusters ◽  
Flexural Properties ◽  
Flexural Property ◽  
Friction Materials ◽  
Friction Performance

This research is to investigate the influences of carbon nanotube (CNT) containing friction powder prepared through different process parameters on flexural properties and friction performance of organic brake friction materials. Experimental results indicate significant influence on flexural property and friction performance of organic brake friction materials when the modified CNT/friction powders are adopted. Particularly for the specimens adopted the modified CNT/friction powders prepared through 2.0 M concentration of catalyst and 30% C2H2show the highest flexural strength, better ductility and toughness, most stable friction coefficient, and lowest weight loss. However, too many amorphous carbon clusters and CNTs aggregation derived from higher concentration of catalyst and ratio of C2H2/N2would cause poor formation of specimens and reduction of reinforcement effectiveness.

The effect of colemanite on the friction performance of automotive brake friction materials

2016 ◽  
Vol 68 (1) ◽  
pp. 92-98 ◽  
Author(s):  
ilker Sugozu ◽  
ibrahim mutlu ◽  
Kezban Banu Sugozu
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Negative Effects ◽  
Wear Performance ◽  
Industrial Firms ◽  
Friction Materials ◽  
Content Type ◽  
Friction Performance ◽  
Brake Lining ◽  
Automotive Brake

Purpose – The purpose of this paper is to investigate use of colemanite (C) upon friction and wear performance of automotive brake lining. Brake lining production with the boron product colemanite addition and braking characterization investigated for development of non-asbestos organic (NAO) brake lining because of negative effects on human health and environmental hazard of asbestos containing linings. During the braking, brake lining is warmed up extremely due to friction, and the high temperature causes to decreasing of breaking performance. Colemanite has high melting temperature, and this makes this material valuable for brake lining. Design/methodology/approach – This study investigated the effect of colemanite (C) upon friction and wear performance of automotive brake lining. Based on a simple experimental formulation, different amounts of boron product colemanite were used and then evaluated using a friction assessment and screening test. In these specimens, half of the samples (shown with H indices) were heat treated in 4 h at 180°C temperature. Friction coefficient, wear rate and scanning electron microscope for friction surfaces were used to assess the performance of these samples. Findings – The results of test showed that colemanite can substantially improve properties of friction materials. The friction coefficient of friction materials modified with colemanite varies steadily with the change of temperature, and the wearing rate of friction materials is relatively low by using colemanite. Heat treatment-applied samples (CH) have provided a higher and stable friction coefficient. These results indicate that colemanite has ideal application effect in various friction materials. Originality/value – This paper fulfils an identified information and offers practical help to the industrial firms working with brake lining and also to the academicians working on wear of materials. Parallel results have been presented between previously reported and present study, in view of brake characteristics and wear resistance. Use of the lower cost and productive organic sources of material are the main improvement of the present study.

scholarly journals Enhanced flexural properties of aramid fiber/epoxy composites by graphene oxide

2019 ◽  
Vol 8 (1) ◽  
pp. 484-492 ◽  
Author(s):  
Yinqiu Wu ◽  
Bolin Tang ◽  
Kun Liu ◽  
Xiaoling Zeng ◽  
Jingjing Lu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Flexural Strength ◽  
Interfacial Shear Strength ◽  
Flexural Modulus ◽  
Weight Fraction ◽  
Interfacial Shear ◽  
Aramid Fiber ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Pure Epoxy

Abstract The reinforcing effect of graphene oxide (GO) in enhancing the flexural strength and flexural modulus of aramid fiber (AF)/epoxy composites were investigated with GO-AFs at a weight fraction of 0.1-0.7%. The flexural strength and flexural modulus of the composite reached 87.16 MPa and 1054.7 MPa, respectively, which were about 21.19% and 40.86% higher than those of the pure epoxy resin, respectively. In addition, the flexural properties and interfacial shear strength (IFSS) of composite reinforced by GO-AFs were much higher than the composites reinforced by AFs due to GO improved the interfacial bonding between the reinforcement material and matrix.

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

scholarly journals Performance Evaluation of Cellulose Nanofiber with Residual Hemicellulose as a Nanofiller in Polypropylene-Based Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1064
Author(s):  
Mohd Nor Faiz Norrrahim ◽  
Hidayah Ariffin ◽  
Tengku Arisyah Tengku Yasim-Anuar ◽  
Mohd Ali Hassan ◽  
Nor Azowa Ibrahim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Weight Loss ◽  
Tensile Strength ◽  
Performance Evaluation ◽  
Flexural Strength ◽  
Decomposition Temperature ◽  
Cellulose Nanofiber ◽  
Hemicellulose Removal ◽  
Reinforcement Material

Residual hemicellulose could enhance cellulose nanofiber (CNF) processing as it impedes the agglomeration of the nanocellulose fibrils and contributes to complete nanofibrillation within a shorter period of time. Its effect on CNF performance as a reinforcement material is unclear, and hence this study seeks to evaluate the performance of CNF in the presence of amorphous hemicellulose as a reinforcement material in a polypropylene (PP) nanocomposite. Two types of CNF were prepared: SHS-CNF, which contained about 11% hemicellulose, and KOH-CNF, with complete hemicellulose removal. Mechanical properties of the PP/SHS-CNF and PP/KOH-CNF showed an almost similar increment in tensile strength (31% and 32%) and flexural strength (28% and 29%) when 3 wt.% of CNF was incorporated in PP, indicating that hemicellulose in SHS-CNF did not affect the mechanical properties of the PP nanocomposite. The crystallinity of both PP/SHS-CNF and PP/KOH-CNF nanocomposites showed an almost similar value at 55–56%. A slight decrement in thermal stability was seen, whereby the decomposition temperature at 10% weight loss (Td10%) of PP/SHS-CNF was 6 °C lower at 381 °C compared to 387 °C for PP/KOH-CNF, which can be explained by the degradation of thermally unstable hemicellulose. The results from this study showed that the presence of some portion of hemicellulose in CNF did not affect the CNF properties, suggesting that complete hemicellulose removal may not be necessary for the preparation of CNF to be used as a reinforcement material in nanocomposites. This will lead to less harsh pretreatment for CNF preparation and, hence, a more sustainable nanocomposite can be produced.

Effect of hybrid thermal cycling and shock on flexural properties of nanoclay/glass/epoxy nanocomposites

2021 ◽  
pp. 096739112110132
Author(s):  
A Bayat ◽  
M Damircheli ◽  
M Esmkhani
Keyword(s):  
Flexural Strength ◽  
Thermal Cycling ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Flexural Stiffness ◽  
Thermal Cycles ◽  
Epoxy Nanocomposites ◽  
Static Conditions

In present research, the flexural properties of glass/epoxy composites reinforced by nanoclay particles (3, 5 and 7 wt.%) under various hybrid thermal cycling and shock loadings (15 and 30 thermal cycles at immediate −70°C and +100°C temperatures) have been investigated. It was found that the flexural strength of 5 wt.% nanoclay/glass/epoxy nanocomposites under 15 and 30 hybrid thermal loadings was enhanced by 19.35% and 20.78%, respectively. Also, after 15 hybrid thermal loadings, the flexural stiffness of 5 wt.% clay/glass/epoxy nanocomposites increased by 9.30% compared to static conditions. More importantly, after 30 hybrid thermal loadings, by adding more filler contents, the flexural stiffness was increased. For instance, at 7 wt.% clay/glass/epoxy nanocomposites, the flexural stiffness enhanced 17.97% compared to neat composite. FESEM morphology images confirmed that presence of optimum filler contents changed the composites inherent properties. Therefore, the outcome of this research can show various remarkable advantages for researchers to apply nanoclay as nanofillers to reinforce composites structures under hybrid thermal cycling and shock applications.

Springback law of high-strength 21-6-9 stainless steel tube in numerical control bending under different process parameters

2015 ◽  
Vol 231 (10) ◽  
pp. 1783-1792 ◽  
Author(s):  
Jun Fang ◽  
Shiqiang Lu ◽  
Kelu Wang ◽  
Zhengjun Yao
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Cross Section ◽  
Process Parameters ◽  
High Strength ◽  
Steel Tube ◽  
Numerical Control ◽  
Stainless Steel Tube ◽  
Outer Diameter ◽  
The Cross

In order to achieve the precision bending deformation, the effects of process parameters on springback behaviors should be clarified preliminarily. Taking the 21-6-9 high-strength stainless steel tube of 15.88 mm × 0.84 mm (outer diameter × wall thickness) as the objective, the multi-parameter sensitivity analysis and three-dimensional finite element numerical simulation are conducted to address the effects of process parameters on the springback behaviors in 21-6-9 high-strength stainless steel tube numerical control bending. The results show that (1) springback increases with the increasing of the clearance between tube and mandrel Cm, the friction coefficient between tube and mandrel fm, the friction coefficient between tube and bending die fb, or with the decreasing of the mandrel extension length e, while the springback first increases and then remains unchanged with the increasing of the clearance between tube and bending die Cb. (2) The sensitivity of springback radius to process parameters is larger than that of springback angle. And the sensitivity of springback to process parameters from high to low are e, Cb, Cm, fb and fm. (3) The variation rules of the cross section deformation after springback with different Cm, Cb, fm, fb and e are similar to that before springback. But under same process parameters, the relative difference of the most measurement section is more than 20% and some even more than 70% before and after springback, and a platform deforming characteristics of the cross section deformation is shown after springback.

scholarly journals Design of Hydraulic Bulging Die for Automobile Torsion Beam and Optimization of Forming Process Parameters

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Kefan Yang ◽  
Youmin Wang ◽  
Kexun Fu
Keyword(s):  
Friction Coefficient ◽  
Process Parameters ◽  
Orthogonal Experiment ◽  
Die Design ◽  
Molding Pressure ◽  
Hydraulic Pressure ◽  
Forming Process ◽  
Torsion Beam ◽  
Supporting Pressure ◽  
Hydraulic Bulging

The hydraulic bulging technology of tubes can provide hollow parts with special-shaped cross sections. Its manufacturing process can effectively improve material utilization and product accuracy and reduce the number and cost of molds. However, the hydraulic bulging process of parts is very complicated. The size of the tube blank, the design of the loading route, and the forming process parameters will have an effect on the molding quality. Closed tubular torsion automobile beam is considered as the research object to study hydraulic bulging die design and optimize forming process parameters. CATIA software is used to design torsion beam product structure and hydraulic bulging die. AMESim software is employed to design hydraulic synchronous control system for cylinders on both sides of the hydraulic bulging die. Mathematical control model is established and verified in Simulink software. DYNAFORM software is applied to conduct numerical simulation of hydraulic expansion. The supporting pressure, molding pressure, friction coefficient, and feeding quantity are taken as orthogonal experiment level factors. Maximum thinning and maximum thickening rates are taken as hydraulic pressure expansion evaluation indexes to complete the orthogonal experiments. Main molding process parameters are analyzed via orthogonal experiment results and optimized by employing the Taguchi method. Optimal hydraulic bulging parameters are obtained as follows: supporting pressure of 20 MPa, molding pressure of 150 MPa, feeding quantity of 25 mm, and friction coefficient of 0.075. Simulation analysis results indicate that the maximum thinning rate is equal to 9.013%, while the maximum thickening rate is equal to 16.523%. Finally, the design of hydraulic bulging die for torsion beam was completed, and its forming process parameters were optimized.

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