A. Mimaroglu, M. Çaliskan and I. Calli
Advanced ceramics such as alumina are widely in use in the design of components for high engineering applications mainly because of their high wear resistance, high compressive…
Abstract
Advanced ceramics such as alumina are widely in use in the design of components for high engineering applications mainly because of their high wear resistance, high compressive strength, low specific density and high temperature capability. Processing and manufacturing of pure alumina products is a difficult and expensive task. Therefore, additional compounds are added to alumina to achieve a more complex component design and to minimise the product processing and manufacturing costs. This paper examines the effects of speed, load values and the addition of Cr2O3, SiO2 and MnO2 compounds on the friction and wear behaviour of alumina ceramic. Wear tests for alumina and alumina samples containing w1.5% Cr2O3 w3% SiO2 and w1.5% MnO2 compounds was carried out on a pin‐on‐disc machine. Tribological tests were under 2.5, 5 and 10N loads and at 0.5, 0.75 and 1m/Sec speeds. The specific wear rates were deduced from mass loss. The wear rate for alumina without additional compounds was in the order of 10–8 to 10–7mm2/N, while the wear rate values for alumina with additional compounds were in the order of 10–6. Moreover, the wear rate showed more sensitivity to the applied load, particularly at low sliding speeds. Furthermore, it is concluded that a 20 per cent decrease in the sintering temperature resulted in 300 per cent increase in the specific wear rate of alumina ceramic material.
The present study aims to find out the best polymer/polymer pair in electrical insulating applications. Moreover, the effects of different polymer counterpart and applied load on…
Abstract
Purpose
The present study aims to find out the best polymer/polymer pair in electrical insulating applications. Moreover, the effects of different polymer counterpart and applied load on the friction and wear behaviour of PA 46 + 30%GFR and unfilled PA 66 thermoplastic polymers are to be studied.
Design/methodology/approach
Friction and wear tests vs PA 46 + 30%GFR and PPS + 30%GFR polymer composites were carried out on a pin‐on‐disc arrangement and at a dry sliding conditions. Tribological tests were performed at room temperature under 20, 40 and 60 N loads and at 0.5 m/s sliding speed.
Findings
The results showed that, the coefficient of friction decreases with the increasing of load (up to 40 N) for PA 46 + 30%GFR composite and polyamide (PA) 66 polymer used in this study. However, above 40 N applied load the coefficient of friction increases. The specific wear rate for PA 46 + 30%GFR and PA 66 against PPS + 30%GFR polymer composite counterpart are about in the order of 10−13 m2/N while the specific wear rate for PA 46 + 30%GFR and PA 66 against PA 46 + 30%GFR polymer composite counterpart are in the order of 10−14 m2/N. For PA 46 + 30%GFR composite and unfilled PA 66 polymers tested the specific wear rate values increased with the increment of load. The highest specific wear rate is for unfilled PA 66 against PPS + 30%GFR with a value of 2.81 × 10−13 m2/N followed by PA 66 against PA 46 + 30%GFR with a value of 2.26 × 10−13 m2/N. The lowest wear rate is PA 46 + 30%GFR polymer composite against PA 46 + 30%GFR polymer composite counterpart with a value of 3.19 × 10−14 m2/N. The average specific wear rates for unfilled PA 66 against PA 46 + 30%GFR is 80 times higher than PA 46 + 30%GFR wear rate while specific wear rates for unfilled PA 66 against PPS + 30%GFR is 100 times higher than that of PA 46 + 30%GFR wear rate. From point view of tribological performance, PA 46 + 30%GFR is a more suitable engineering thermoplastic composite materials for electrical contact breaker applications.
Research limitations/implications
In the present work, tribological tests were performed only at room temperature under three different loads and a sliding speed. This is the limitation of the work.
Practical implications
This work is easily used for industrial polyamides to check their tribological behaviours.
Originality/value
This is an original and experimental study and it will be useful both for academicians and for industrial sides.
Details
Keywords
Dewan Muhammad Nuruzzaman, Mohammad Asaduzzaman Chowdhury and Mohammad Lutfar Rahaman
The present paper seeks to report the effect of duration of rubbing on friction coefficient for different polymer and composite materials. Variations of friction coefficient and…
Abstract
Purpose
The present paper seeks to report the effect of duration of rubbing on friction coefficient for different polymer and composite materials. Variations of friction coefficient and wear rate with the normal load are also investigated experimentally when stainless steel (SS 304) pin slides on different types of materials such as cloth‐reinforced ebonite (commercially known as gear fiber), glass fiber‐reinforced plastic (glass fiber), nylon and polytetrafluoroethylene (PTFE).
Design/methodology/approach
A pin on disc apparatus is designed and fabricated. During experiment, the rpm of test samples was kept constant and relative humidity was 70 percent.
Findings
Studies have shown that the values of friction coefficient depend on applied load and duration of rubbing. It is observed that the values of friction coefficient decrease with the increase of normal load for glass fiber, nylon and PTFE. Different trend is observed for gear fiber, i.e. coefficient of friction increases with the increase of normal load. It is also found that wear rate increases with the increase of normal load for all the materials. The magnitudes of friction coefficient and wear rate are different for different materials.
Practical implications
It is expected that the applications of these results will contribute to the design of different mechanical components of these materials.
Originality/value
Within the observed range of applied normal load, the relative friction coefficient and wear rate of gear fiber, glass fiber, nylon and PTFE are experimentally investigated.
Details
Keywords
H. Unal and A. Mimaroglu
The tribological problems of polymers have received more attention because of their suitability for fabricating machine elements in food industry, which require self lubrication…
Abstract
The tribological problems of polymers have received more attention because of their suitability for fabricating machine elements in food industry, which require self lubrication environment. In this investigation, we studied and explored the influence of test speed and load values on the friction and wear behaviour of PTFE, POM and PEI polymers. Friction and wear tests of PTFE, POM and PEI vs steel were carried out at dry condition on a pin‐on‐disc arrangement. Tribological tests were carried out at room temperature, under 5, 10 and 15 N loads and at 0.5, 0.75 and 1 m/s speeds. The specific wear rates were deduced from mass loss. The results showed that, for all the polymers used in this investigation, the coefficient of friction increases linearly with the increase in load. Moreover, for the load and speed range of this investigation, the wear rate showed very little sensitivity to the applied load and large sensitivity to test speed, particularly at high load values.
Kamaljit Singh Boparai, Rupinder Singh and Harwinder Singh
In this study the friction and wear behavior of fused deposition modeling (FDM) parts fabricated with composite material and acrylonitrile butadienestyrene (ABS) material…
Abstract
Purpose
In this study the friction and wear behavior of fused deposition modeling (FDM) parts fabricated with composite material and acrylonitrile butadiene styrene (ABS) material feedstock filament were realized and compared under dry sliding conditions.
Design/methodology/approach
The tests were performed by applying the load of 5, 10, 15 and 20 N with sliding velocity of 0.63 m/s for the duration of 5 and 10 min at room temperature.
Findings
The results highlight various wear mechanisms such as adhesion, abrasion and fatigue during the investigation. It was observed that the wear volume, friction force, friction co-efficient and temperature were sensitive to the applied load and time duration. The composite material showed a remarkable improvement in wear properties as compared to the ABS material.
Research limitations/implications
The investigations reported in the present research work is based on comparative analysis (of composite material and ABS material feedstock filament). The results may be different in practical applications because of different operating conditions.
Practical implications
The parts fabricated with proposed composite material feedstock filament are highly wear resistant than basic ABS filament. This may lead to the development of better wear resistance components for numerous field applications.
Originality/value
The potential of this research work is to fabricate FDM parts with composite material feedstock filament to cater need of wear resistant industrial components.
Details
Keywords
The purpose of this paper is to investigate the friction and wear performance of pure polycarbonate (PC) and 5-30 per cent wollastonite-filled (by weight) PC were comparatively…
Abstract
Purpose
The purpose of this paper is to investigate the friction and wear performance of pure polycarbonate (PC) and 5-30 per cent wollastonite-filled (by weight) PC were comparatively evaluated under dry sliding conditions. Wear tests were carried out at room temperature under the loads of 5-20 N and at the sliding speeds of 0.5-1.5 m/s.
Design/methodology/approach
The microstructures of the wollastonite, pure PC and composites were examined by optical microscopy, scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. The friction and wear tests were realized using a pin-on-disk arrangement against the hardened AISI 4140 steel.
Findings
The result of this study indicated that the coefficients of friction wear rate of the materials were significantly influenced by an increase in wollastonite content. The friction coefficient of the PC was getting decreased from 0.457 to 0.198 with an increase in wollastonite content, depending on applied loads and sliding speeds. On the other hand, the results showed that the wear rates of pure PC and wollastonite-filled PCs decreased with an increase in loads. The wear rate of the PC decreased from 1.2 × 10−6 to 8.7 × 10−6 mm3/m with an increase in wollastonite content, depending on applied loads.
Originality/value
There are many reports which deal with the friction and wear performance of the polymers and polymer composites. However, the effect of wollastonite effect on tribological performance of PC has up to now not been extensively researched.
Qingyuan Wu, Changchen Zhan, Fu Lee Wang, Siyang Wang and Zeping Tang
The quick growth of web-based and mobile e-learning applications such as massive open online courses have created a large volume of online learning resources. Confronting such a…
Abstract
Purpose
The quick growth of web-based and mobile e-learning applications such as massive open online courses have created a large volume of online learning resources. Confronting such a large amount of learning data, it is important to develop effective clustering approaches for user group modeling and intelligent tutoring. The paper aims to discuss these issues.
Design/methodology/approach
In this paper, a minimum spanning tree based approach is proposed for clustering of online learning resources. The novel clustering approach has two main stages, namely, elimination stage and construction stage. During the elimination stage, the Euclidean distance is adopted as a metrics formula to measure density of learning resources. Resources with quite low densities are identified as outliers and therefore removed. During the construction stage, a minimum spanning tree is built by initializing the centroids according to the degree of freedom of the resources. Online learning resources are subsequently partitioned into clusters by exploiting the structure of minimum spanning tree.
Findings
Conventional clustering algorithms have a number of shortcomings such that they cannot handle online learning resources effectively. On the one hand, extant partitional clustering methods use a randomly assigned centroid for each cluster, which usually cause the problem of ineffective clustering results. On the other hand, classical density-based clustering methods are very computationally expensive and time-consuming. Experimental results indicate that the algorithm proposed outperforms the traditional clustering algorithms for online learning resources.
Originality/value
The effectiveness of the proposed algorithms has been validated by using several data sets. Moreover, the proposed clustering algorithm has great potential in e-learning applications. It has been demonstrated how the novel technique can be integrated in various e-learning systems. For example, the clustering technique can classify learners into groups so that homogeneous grouping can improve the effectiveness of learning. Moreover, clustering of online learning resources is valuable to decision making in terms of tutorial strategies and instructional design for intelligent tutoring. Lastly, a number of directions for future research have been identified in the study.
Details
Keywords
Baldev Singh Rana, Gian Bhushan and Pankaj Chandna
The purpose of current study deals with the development and wear testing of jute and cotton fiber reinforced with nano fly ash-based epoxy composites. Performance of waste cotton…
Abstract
Purpose
The purpose of current study deals with the development and wear testing of jute and cotton fiber reinforced with nano fly ash-based epoxy composites. Performance of waste cotton fabric nano hybrid composites are compared with waste jute fabric nano hybrid composites.
Design/methodology/approach
Basic hand layup technique was used to develop composites. To optimize the parameters and design of experiments, Taguchi design was implemented to test wear rate and co-efficient of friction as per ASTM standards. Performance of waste cotton fabric nano hybrid composites is compared with waste jute fabric nano hybrid composites.
Findings
Result shows that nano fly ash lowers the wear rate and co-efficient of friction in developed composites. Findings reveals that hybrid composites of waste jute Fabric with 3 Wt.% of nano fly ash performed best amongst all composites developed. Morphology of nano composites worn out surfaces are also analyzed through SEM.
Practical implications
Practically, textile waste, i.e. jute, cotton and nano fly ash (thermal power plant) all wastes, is used to develop composites for multi-function application.
Social implications
Wastes are reused and recycled to develop epoxy-based composites for sustainable structures in aviation.
Originality/value
To the best of the authors’ knowledge, nano fly ash and jute, cotton combination is used for the first time to develop and test for wear application.
Details
Keywords
Huseyin Unal, Salih Hakan Yetgin and Fehim Findik
– The purpose of the study was to find the best performance polymer material to be used in railway car bogies.
Abstract
Purpose
The purpose of the study was to find the best performance polymer material to be used in railway car bogies.
Design/methodology/approach
Wear tests and optical and scanning electron microscopy were used.
Findings
The friction coefficients of ultra-high-molecular-weight polyethylene (UHMWPE) and Nylon 6 polymers, as opposed to AISI 4140 steel, reduced with the increment of applied loads. With the increment of sliding speed, the friction coefficient increased in both UHMWPE and Nylon 6 polymers. The specific wear rate of the UHMWPE polymer was determined to be about 10-14 m2/N, whereas the rate of Nylon 6 was determined to be 10-13 m2/N.
Practical implications
The aim of the study was to find the best performance polymer material to be used in railway car bogies.
Originality/value
The friction and wear performance of UHMWPE and Nylon 6 engineering polymers were studied and compared to their AISI 4140 steel counterparts. It is an original work and it is not published in any media.
Huseyin Unal, Salih Hakan Yetgin, Yasin Yılmaz and Fehim Findik
This study aims to investigate the tribological performance of neat polyamide-imide (PAI) and PAI composite (PAI + 12% graphite + 3% polytetrafluoroethylene [PTFE]) under varying…
Abstract
Purpose
This study aims to investigate the tribological performance of neat polyamide-imide (PAI) and PAI composite (PAI + 12% graphite + 3% polytetrafluoroethylene [PTFE]) under varying mediums and conditions, including dry sliding, distilled water and seawater lubrication, to determine their suitability for high-stress applications.
Design/methodology/approach
Tribological tests were conducted using a pin-on-disc setup with AISI 316 L stainless steel (SS) as counterface. Experiments were carried out under loads of 150 and 300 N and sliding speeds of 1.5 and 3.0 m/s. Values of temperatures, friction coefficients and wear rates were recorded to analyze the effect of fillers and lubrication mediums.
Findings
The PAI composite outperformed the neat PAI under all conditions, showing significant reductions in friction coefficients and wear rates. Seawater lubrication yielded the best results, achieving friction coefficients of 0.05 and 0.01 and specific wear rates of 18.10−16 m²/N and 1.10 −15 m²/N, for neat PAI and PAI composite, respectively. Graphite and PTFE fillers enhanced lubrication, reduced surface temperatures and mitigated abrasive and adhesive wear mechanisms. Superior cooling and lubrication effects of the seawater contributed to these improvements.
Originality/value
Previous studies mainly focused on dry sliding and distilled water lubrication for the PAI and its composites, with no research on the seawater conditions. This study compares the tribological behaviors of the neat PAI and PAI composite against AISI 316 L SS under dry sliding, distilled water and seawater lubrication.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0302/