Shear-area variation: A mechanism that reduces hydrodynamic friction in macro-textured piston ring liner contacts

Zimmer, Maximillian; Vlădescu, Sorin-Cristian; Mattsson, Lars; Fowell, Mark; Reddyhoff, Tom

doi:10.1016/j.triboint.2021.107067

Cited by 16 publications

(10 citation statements)

References 38 publications

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Section: Introductionmentioning

confidence: 99%

“…21 Alternatively, macroscale texture has recently been shown to reduce friction in the full-film regime, thanks to the shear area reduction mechanism. 31 In addition, surface texture has been shown to reduce wear either by increased surface separation due to film thickness increase and/or by acting as debris traps. 20,21 In a series of recent studies, Watanabe et al 32,33 combined IL swollen CPBs with micrometer-sized grooves and nanoperiodic structures to achieve a significant increase in durability compared to CPBs grafted onto non-textured surfaces.…”

Section: Introductionmentioning

confidence: 99%

“…Specific pocket geometry criteria (shape, orientation, and spacing) have also been show to further reduce friction. , When optimized in this way, surface texture coverage as low as 5% can generate friction reductions of up to 82%, compared to nontextured components . Alternatively, macroscale texture has recently been shown to reduce friction in the full-film regime, thanks to the shear area reduction mechanism . In addition, surface texture has been shown to reduce wear either by increased surface separation due to film thickness increase and/or by acting as debris traps. , …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Exploiting the Synergy between Concentrated Polymer Brushes and Laser Surface Texturing to Achieve Durable Superlubricity

Vlădescu

Tadokoro

Miyazaki

et al. 2022

ACS Appl. Mater. Interfaces

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Friction continues to account for the bulk of energy losses in mechanical systems, with an estimated 23% of the world’s total energy consumption used to overcome friction. Concentrated polymer brushes (CPBs) have recently attracted significant scientific and industrial attention, given their ability to achieve superlubricity (i.e., coefficients of friction below 0.01); however, understanding the mechanistic interactions underlying their wear performance has been largely overlooked. Herein, we employ a custom-built optical test apparatus to investigate the inter-dependencies between CPBs and laser-produced surface texture (LST), assessing for the first time the friction, film thickness, and wear behavior in situ and simultaneously. Recent developments in picosecond laser etching allowed us to graft CPBs atop the finest laser-etched matrix of micron-sized dimples reported in literature to date. At low sliding speeds, combined CPB–LST reduces the coefficient of friction to 0.0006, while increasing the CPB durability by up to 34% through a lateral support mechanism offered by the textured micro-features. Furthermore, the imaging results shed light on CPB failure mechanisms. Both these mechanisms of lateral support and failure propagation impact the wear resistance of CPBs and are important in the development of CPBs for future applications (e.g., in low-speed bearings functioning under controlled abrasive wear conditions).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Exploiting the Synergy between Concentrated Polymer Brushes and Laser Surface Texturing to Achieve Durable Superlubricity

Vlădescu

Tadokoro

Miyazaki

et al. 2022

ACS Appl. Mater. Interfaces

Self Cite

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“…Zimmer et al tested macro textured cylinder liner made from mild steel against AISI52100 steel ring samples on a reciprocating rig. According to the analysis and experimental results during hydrodynamic lubrication, the friction reduction is significant, but in the mixed lubrication state, the reduction is lower and even worsens the friction values compared untextured samples, as the large cavities break the fluid film [78].…”

Section: Tribological Test With Laser Textured Piston Ringcylinder Li...mentioning

confidence: 98%

A Review on Friction Reduction by Laser Textured Surfaces in Internal Combustion Engines

et al. 2022

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The internal combustion engine will be required as a bridge-technology in the upcoming decades to achieve a significant reduction in local emissions in the mobility, and logistics sector. Alternative fuel technologies will present new mechanical engineering challenges, including increasing efficiency and reducing mechanical losses. Textured surfaces with appropriate manufacturing parameters can enhance lubrication, and reduce friction in sliding and rolling contacts, e.g., journal bearings, or the piston ring -cylinder subsystem. This paper gives an overview of 80 scientific works related to laser surface technologies, with an emphasis on surface texturing for friction reduction from the viewpoint of engine development. The most common texture types, further directions, and general challenges are highlighted in the summary.

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“…Surface cavities can reduce abrasive wear in harsh contact conditions by retaining wear and contaminant particles (debris trapping effect), as well as work as micro-reservoirs and secondary oil suppliers (oil reservoir effect) [6]. Under mixed and (elasto) hydrodynamic lubrication, friction can be reduced by the interplay of different mechanisms, such as the (i) micro-hydrodynamic bearing (boosting in the fluid pressures due to the texture-induced cavitation at the divergent regions of the textures) [7], (ii) inlet suction (lubricant sucking into the interface due to the difference between the supply pressure and the cavitation pressure) [3,8,9], and (iii) shear-area variation (decrease of the fluid and contact shear stresses over the contact area) [10] mechanisms. Furthermore, under boundary and mixed lubrication regimes, textures can influence the sealing performance and percolation behavior.…”

Section: Introductionmentioning

confidence: 99%

Tribological Performance of Random Sinter Pores vs. Deterministic Laser Surface Textures: An Experimental and Machine Learning Approach

Boidi¹,

Grützmacher²,

Varga³

et al. 2022

Tribology of Machine Elements - Fundamentals and Applications

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This work critically scrutinizes and compares the tribological performance of randomly distributed surface pores in sintered materials and precisely tailored laser textures produced by different laser surface texturing techniques. The pore distributions and dimensions were modified by changing the sintering parameters, while the topological features of the laser textures were varied by changing the laser sources and structuring parameters. Ball-on-disc tribological experiments were carried out under lubricated combined sliding-rolling conditions. Film thickness was measured in-situ through a specific interferometry technique developed for the study of rough surfaces. Furthermore, a machine learning approach based on the radial basis function method was proposed to predict the frictional behavior of contact interfaces with surface irregularities. The main results show that both sintered and laser textured materials can reduce friction compared to the untextured material under certain operating conditions. Moreover, the machine learning model was shown to predict results with satisfactory accuracy. It was also found that the performance of sintered materials could lead to similar improvements as achieved by textured surfaces, even if surface pores are randomly distributed and not precisely controlled.

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Shear-area variation: A mechanism that reduces hydrodynamic friction in macro-textured piston ring liner contacts

Cited by 16 publications

References 38 publications

Exploiting the Synergy between Concentrated Polymer Brushes and Laser Surface Texturing to Achieve Durable Superlubricity

Exploiting the Synergy between Concentrated Polymer Brushes and Laser Surface Texturing to Achieve Durable Superlubricity

A Review on Friction Reduction by Laser Textured Surfaces in Internal Combustion Engines

Tribological Performance of Random Sinter Pores vs. Deterministic Laser Surface Textures: An Experimental and Machine Learning Approach

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