scholarly journals Evaluation of Tribological Properties of Bearing Materials for Marine Diesel Engines Utilising the Contact Voltage Method

2021 ◽  
Vol 11 (17) ◽  
pp. 7811
Author(s):  
Biao Wan ◽  
Jianguo Yang ◽  
Qinghe Wang

The contact voltage (CV) method, which can detect miniature failures, has been tested under laboratory conditions to monitor the condition of bearings. In this study, the bearing materials for marine diesel engines, aluminium and copper alloy, were tested on a bearing fatigue wear test bench in the boundary lubrication state, which was found through tests of the different parameters. The frictional torque, the oil film thickness and the bearing temperature were measured, as well as the CV signals. The possibility of using the CV technique to monitor the condition of the bearings was also assessed by evaluating the tribological properties. After 10 h of the test, the aluminium alloy bearing was worn to the alloy layer. Then, the wear-reducing layer on the surface of the bearing slowly peeled off, and the wear was intensified. Due to its higher wear-resisting property, the amount of wear on the copper alloy bearing increased slowly. After 20 h of the fatigue wear test, the aluminium alloy bearing became severely worn, the CV characteristic was up to 81% of the initial value, the bearing temperature increased by 6.3%, and the torque value increased by 32%. This indicates that the CV method is more sensitive to wear failure. Due to better wear resistance, the copper alloy bearing showed only slightly wear and a small increase in its CV value. The main contribution is that the CV method is useful for monitoring the lubricated condition and for evaluating the tribological properties of bearings. This research has laid technical foundations for the engineering of the sliding bearing wear monitoring system based on the CV method.

2014 ◽  
Vol 81 (7) ◽  
Author(s):  
N. W. Khun ◽  
H. Zhang ◽  
C. Y. Yue ◽  
J. L. Yang

Self-lubricating and wear resistant epoxy composites were developed via incorporation of wax-containing microcapsules. The effects of microcapsule size and content and working parameters on the tribological properties of epoxy composites were systematically investigated. The incorporation of microcapsules dramatically decreased the friction and wear of the composites from those of the epoxy. The increased microcapsule content or the incorporation of larger microcapsules decreased the friction and wear of the epoxy composites due to the larger amount of released wax lubricant via the rupture of microcapsules during the wear test. The friction of the composites decreased with increased normal load as a result of the promoted wear of the composites and the increased release of the wax lubricant.


2013 ◽  
Vol 372 ◽  
pp. 507-511
Author(s):  
Hitonobu Koike ◽  
Kenji Kanemasu ◽  
Kiyoto Itakura ◽  
Shota Okazaki ◽  
Masahiro Takamiya ◽  
...  

In this work, wear of reinforced poly-ether-ether-ketone (PEEK) polymer bushes in friction against 7075 aluminium alloy cam plates or titanium crankshafts is investigated in order to establish the application possibilities in transmission parts in humanoid robot joints under high load torque. The PEEK bush wear requires close examination as well as the input axis-output axis transmission error (backlash). Sliding wear tests were performed on bushes under 4000 kgfcm (392 Nm) load torque, while the cam plate oscillated in the humanoid robot leg joint evaluation system. The robot joint using PEEK bush achieved quite small backlash after the fatigue wear test.


1990 ◽  
Vol 27 (04) ◽  
pp. 237-249
Author(s):  
Anastassios N. Perakis ◽  
Bahadir Inozu

Some essential steps for the application of reliability, availability, and maintainability (RAM) techniques to marine diesel engines are presented. The paper begins with a summary of the basic concepts of reliability engineering, followed by a survey of the relevant literature on RAM applications to the marine industry and to marine diesel engines in particular. Next, the results of an informal survey of the reliability, maintenance, and replacement practices of Great Lakes operators are presented. Finally, the first two steps for a RAM application, failure modes and effects analysis and fault tree analysis, are introduced and applied for a prototype Colt-Pielstick marine diesel engine.


2015 ◽  
Author(s):  
Jerry Ng ◽  
Kaisa Honkanen

Emulsified fuel technology has been developed since the early 1980’s to the improve combustion efficiency of marine diesel engines by creating a secondary atomization effect after the initial fuel injection. The main challenge is to measure the improved sfoc of ships accurately and reliably. This paper presents a proposed method to measure the sfoc accurately and reliably to the order of 1%. Electronic governor also poses new challenge to measuring the sfoc of ships burning emulsified fuel. Meanwhile, fuel types supplied to ship owners are of increased varying properties although still complying to ISO8217 standard. This paper describes the innovations in emulsified fuel technology that were developed to meet these challenges.


Author(s):  
Л.Б. Леонтьев ◽  
Н.П. Шапкин ◽  
А.Л. Леонтьев ◽  
В.Н. Макаров ◽  
А.В. Арон

Повышение долговечности трибосопряжений судовых дизелей, определяющих их ресурс, представляет собой актуальнейшую проблему, обусловленную как безопасностью мореплавания, так и экономическими факторами. Основной причиной отказов коленчатых валов двигателей, определяющих необходимость капитального ремонта, является износ шеек. Решение проблемы повышения износостойкости и, соответственно, долговечности связано с применением трибоактивных присадок в смазку. Несмотря на глубокие и обстоятельные исследования в области применения органо-неорганических материалов для использования в качестве присадок в моторное масло для повышения долговечности трибоузлов осуществить выбор оптимального материала для конкретных условий практически невозможно, так как исследования выполнены для различных условий эксплуатации и по различным методикам. Цель работы – разработка триботехнической присадки к моторным маслам, обеспечивающей повышение надежности и эффективности технической эксплуатации судовыхсреднеоборотных дизелей путем формирования тонкопленочного металлокерамического покрытия на поверхностях трения стальных деталей трибоузлов, позволяющего получить оптимальный комплекс параметров материала износостойкого покрытия. В работе представлены исследования эксплуатационных свойств присадок в моторное масло 17 органо-неорганических триботехнических материалов 4 групп — природные и искусственные полимеры, из которых были изготовлены свыше 20 композиций и композитов. Установлено, что наиболее перспективным является использование нанокомпозитов на основе вермикулита, модифицированного кислотой, в качестве присадок в моторное масло, так как они обладают минимальными коэффициентом трения при граничной смазке (0,007–0,014) а также высокой износостойкостью стали 40Х и обеспечивают минимальную величину скорости изнашивания вкладыша подшипника, благодаря чему повышается ресурс трибосопряжения более, чем в 3 раза, и соответственно снижаются эксплуатационные расходы. Increasing the durability of the tribo-couplings of marine diesel engines, which determine their resource, is an urgent problem due to both the safety of navigation and economic factors. The main reason for engine crankshafts failures, which determine the need for major repairs, is the wear of the necks. The solution to the problem of increasing wear resistance and, accordingly, durability is associated with the use of triboactive additives in the lubricant. Despite in-depth and thorough research in the field of application of organo-inorganic materials for use as additives in engine oil to increase the durability of tribo-nodes, it is almost impossible to choose the optimal material for specific conditions, since the studies were carried out for various operating conditions and according to various methods. The purpose of the work is to develop a tribotechnical additive to motor oils that provides an increase in the reliability and efficiency of technical operation of medium-speed marine diesel engines by forming a thin-film metal-ceramic coating on the friction surfaces of steel parts of tribo-nodes, which allows to obtain an optimal set of parameters of the wear-resistant coating material. The paper presents studies of the operational properties of additives in engine oil of 17 organo-inorganic tribotechnical materials of 4 groups — natural and artificial polymers, from which more than 20 compositions and composites were made. It has been established that the most promising is the use of nanocomposites based on vermiculite modified with acid as additives in engine oil, since they have a minimum coefficient of friction with boundary lubrication (0.007-0.014) as well as high wear resistance of 40X steel and provide a minimum wear rate of the bearing liner, thereby increasing the tribo-tension life by more than 3 times, and, accordingly, operating costs are reduced.


Author(s):  
C-T Duong ◽  
J-S Nam ◽  
E-M Seo ◽  
B P Patro ◽  
J-D Chang ◽  
...  

The tribological properties of engineering and biological materials have been investigated at microscale levels through the calculation of the surface roughness and frictional coefficient using atomic force microscopy (AFM). Although a number of previous studies have reported the frictional coefficients of diverse bearing materials in total hip arthroplasty (THA), the relationship between the surface roughness and frictional coefficient of bearing materials of THA have not been reported, and furthermore, the tribological properties for different wear regions of a cobalt-chromium (Co—Cr) femoral head have not been well identified. Therefore, the objective of this study is to investigate the relationships between the surface roughness, frictional coefficient, and hardness for both the main-wear and the least-wear regions of a Co—Cr femoral head 10 years after THA. The average Vickers hardness of the Co—Cr femoral head was 380.7 ± 11.3 HV. With the scanned area of 25 μm×25 μm through AFM, the frictional coefficients of the main-wear and the least-wear regions were 0.229 ± 0.054 and 0.243 ± 0.059, respectively, and showed no statistical differences between these two regions ( p = 0.449). However, differences in the surface roughness ( Rq) between the main-wear region ( Rq = 96.5 ± 26.2 nm) and the least-wear region ( Rq = 17.7 ± 4.2 nm) were statistically significant ( p<0.0001). The results of the current study suggest that the frictional property of the Co—Cr femoral head is not significantly correlated with its surface roughness, and also provide guidelines for improving the surface characteristics of metallic implant materials.


1998 ◽  
Author(s):  
Takashi Tomikawa ◽  
Haruyuki Oshiro ◽  
Katsuyuki Hashizume ◽  
Soji Kamiya
Keyword(s):  

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