Analysis of Connecting Rod Bearing Wear

A study was done to determine the effect of best stacking sequence (position and orientation) on the mechanical properties, friction and wear response of hybrid composites. The main purpose of the study was to determine the best available stacking sequence for which the physical, mechanical and three body abrasive wear rate is optimum. Test for mechanical properties (tensile strength, flexural strength, inter laminar shear strength, impact strength and hardness) was done on glass-carbon hybrid composites. The composites were then subjected to test for three body abrasive wear on a designed experimental setup. Five different factors (sliding velocity, fabric weight percentage, normal load, sliding distance and abrasive particle size) varied in steps to evaluate the friction and three body abrasive wear response of the composites. The design of experiment using Taguchi’s orthogonal array and analysis of variance (ANOVA) was applied to find out minimum specific wear rate. The results revealed the significance in arrangement of two different layers of fabric (glass and carbon) and the difference in properties obtained by them. Using Taguchi experimental analysis it has been observed that three body abrasive wear rate is minimum at 72 cm/s sliding velocity, 30 wt.% fabric content, 80 N normal load, 90 m sliding distance and 125 μm abrasive particle size. The scanning electron microscope (SEM) studies revealed the dynamics of three-body abrasive wear and underlying micro-mechanisms that result in the analysis of three body abrasive wear.

Wear performance of oil lubricated silicon nitride sliding against various bearing steels

On the wear and failure of high speed roller bearings

Microstructural, mechanical and tribological characterization of Cu-Co-Ni-Be alloy processed via equal channel angular pressing

Investigation of the durability and performance of autoclave-cured, woven carbon fiber-reinforced polymer composite gears in mesh with a steel pinion

To improve the tribological properties of polar crane copper alloy bearings to withstand wear under dry sliding wear and grease lubrication at low temperatures, three kinds of coating materials modified by incorporating WS2 and SiC into polyamide‐imide/polyimide‐phenolic epoxy resin were designed. These composite coatings were sprayed on the surfaces of CuPb22.5Sn2.5 copper alloys by liquid spraying technique. Firstly, the tribological experiments were performed with three different coatings. Then, nanoindentation testing and wear morphology analysis were conducted. The results show that the hardness of the composite coatings decreases with the increase of WS2. As the content of WS2 increases, the coefficients of friction (CoFs) of coatings decreases under dry sliding wear. The S2 coating filled with 7.5 wt% WS2 exhibits the lowest wear rate and the best wear resistance under low temperature and dry sliding wear. The coatings form a lubricating film on the worn surface under dry sliding wear at −70°C, improving the wear resistance of the coatings. The primary wear mechanisms are adhesive wear and fatigue wear. The wear rates of the coatings increase with the increasing content of WS2 under low‐temperature grease lubrication. The S1 coating filled with 5.0 wt% WS2 exhibits the lowest wear. The S1 coating demonstrates a CoF of 0.07 and a wear rate of 6.5 × 10−6 mm3N−1 m−1 at 0°C, showing excellent friction‐reducing and wear‐resistant properties. The primary wear mechanism is adhesive wear. The wear mechanisms of polymer coatings are closely related to temperature. The dominant wear mechanisms transfer from abrasive wear to adhesive wear and fatigue wear under dry sliding wear and decreasing temperature. The wear mechanisms transfer from predominantly adhesive and abrasive wear to adhesive wear, fatigue wear, and abrasive wear under grease lubrication. The hardness of the coatings and the behavior of the polymer at various low temperatures are the primary factors that affect the differing wear mechanisms.

Mechanical and three-body abrasive wear behaviour of PMMA/TPU blends

The spool valve is the controlling component of the hydraulic system. The wear of spool valves can lead to large gap between the spool and valve sleeve, causing greater internal leakage. It can be even worse that the spool would be skewed and then chucked in the valve sleeve, which makes the whole hydraulic system fail. Thus this paper is focused on the hydraulic spool valve regarding the above problem. Firstly, the adhesive wear and the three-body abrasive wear are determined by analyzing the wear mechanism of the hydraulic spool valve. Then the accuracy of the mechanism analysis is verified by the following wear test. Secondly, with the analysis on the mechanism coupling relationships, the mechanism coupling model is established to demonstrate the coupling relationships of the adhesive wear and the three-body abrasive wear. Finally, a wear test is designed and conducted to identify the parameters of the coupling model as well as to verify the accuracy of the model. In brief, this paper proposes a method to establish the wear mechanism coupling model of the adhesive wear and the three-body abrasive wear for the hydraulic spool valve. The paper can be a reference for the mechanism coupling modeling and advances the research on the mechanism coupling relationship.

Compliant layer knee bearings. Part II: Preliminary wear assessment

The primary objective of this study was to evaluate bearing wear during clinical use of the HeartMate II (HMII) left ventricular assist device. Bearings obtained from HMII pumps explanted after clinical use in the Destination Therapy and Bridge to Transplantation clinical trials were analyzed for wear using surface profilometry. Geometric profile variations measured on the inlet bearing ball were used to calculate the wear. Bearing wear was normalized to the total pump support duration to obtain an annualized bearing wear rate. Bearing life was estimated assuming a linear wear rate, as the time to reach a wear limit of 25 µm, which includes a 3× safety factor, to ensure that there is no contact between the rotor blades and the blood bore housing. One hundred and eighty-three bearings from left ventricular assist devices implanted in 181 patients were analyzed. Average age of the patients was 56.3 ± 14.6 years, 76% were male, 46% had an ischemic etiology of heart failure. Mean support duration for the pumps was 363 ± 349 days (median: 238, range: 1-1,621 days). Sixty pumps (33%) were explanted at heart transplantation, 20 (11%) after device replacement, 6 (3%) for ventricular recovery, 94 (51%) after patient death, and 3 (2%) were explanted for other reasons. Mean bearing wear was 0.59 ± 0.37 µm (median: 0.46 µm [5-95% interval: 0.25-1.48]). The median bearing wear rate for patients supported for at least 1 year was 0.30 [5-95% interval: 0.09-0.94] µm/yr. The 5-95% limits of the bearing wear rate corresponded to an estimated bearing life between 27 and 269 years. The pump having the highest bearing wear rate (1.46 µm/yr) had an estimated bearing life of at least 17 years. HMII bearing wear is extremely small, with an estimated bearing life well in excess of 17 years; it is not a limiting factor for long-term support with the HMII left ventricular assistive system.

A critical comparison of the tribocorrosive performance in highly-alkaline wet medium of ultrafine-grained WC cemented carbides with Co, Co+Ni, or Co+Ni+Cr binders

Microstructure and tribological characteristics of WC/Ni-based plasma transferred arc welding (PTAW) overlays have been investigated. WC/Ni-based composite overlays were deposited under same conditions with different percent of WC particle (20-70 wt.%) in the 304L stainless steel. Reciprocating wear tests were undertaken according to the ASTM G133-05 standard. Microstructure and surface micrographs of the cross-section and worn surfaces were characterized. The results indicated that the wear rate decreased with the increasing percent of WC particle, revealing no visible decrease in wear when the percent of WC particle reached more than 50 wt.%. Coating with 50 wt.% WC particle possessed a fine abrasion resistance due to a homogeneous microstructure. Furthermore, at a low concentration (20 wt.% to 40 wt.%), the wear mechanism were adhesive wear and oxidation wear, whereas in 50wt.% WC particle, the main wear mechanism were adhesive wear and abrasive wear. In the case of high concentration of WC particle (above 50 wt.%), the predominant wear mechanism was three-body abrasive wear.

ABSTRACTAl/Al–Cu–Cr–Fe metal matrix composites (MMCs) were fabricated using spark plasma sintering (SPS). Quasicrystalline Al–Cu–Cr–Fe was preserved in the composites and it formed strong mechanical interlocking with Al matrix. Comparative study on the tribological behavior of the Al/Al–Cu–Cr–Fe MMCs and pure Al was performed. The wear rate of the Al/Al–Cu–Cr–Fe MMCs was about one-sixth of pure Al. Al/Al–Cu–Cr–Fe MMCs have a lower overall coefficient of friction compared with pure Al. The incorporation of Al–Cu–Cr–Fe particles into Al matrix significantly improves the wear resistance and also alters the wear mechanisms: plowing and adhesive wear were the dominant wear mechanism of pure Al and three-body abrasive wear was the main wear mechanism in Al/Al–Cu–Cr–Fe MMCs.

Three-body abrasive wear of ceramic materials

Transitions between two-body and three-body abrasive wear: influence of test conditions in the microscale abrasive wear test