3. Introduction
• Bearings are essential mechanical components used to enable smooth and
controlled motion between two moving parts. They reduce friction by providing a
low-resistance interface between surfaces in contact, allowing rotational or linear
movement with minimal effort.
• Types of bearing
• Ball Bearings
• Roller Bearings
– Cylindrical Roller Bearings
– Tapered Roller Bearings
– Spherical Roller Bearings
• Plain Bearings
• Thrust Bearings
4. • Journal Bearings support rotating shafts using a thin layer of lubricant to
reduce friction. They're plain bearings that rely on fluid film lubrication, separating
the rotating shaft from a stationary housing. Common in heavy machinery and
engines, they handle substantial radial loads at lower speeds by creating a
lubricating film between the shaft and housing. Maintenance, proper lubrication,
and material quality are crucial for their effective function
• Porous material have interconnected voids or pores within their
structure, creating spaces that can hold gases, liquids, or other substances. These
materials come in various forms like sponges, foams, aerogels, or powders, and
their porosity can range from microscopic to macroscopic scales.
5. Porous materials can exhibit self-lubricating properties due to their ability to retain
and release lubricants within their structure. When these materials are
impregnated or infused with lubricants like oils or solid lubricants, the pores act as
reservoirs that hold the lubricant.
• Porous materials have interconnected voids or pores within their structure.
• They can retain lubricants within these pores and gradually release them during
motion or frictional contact.
• The released lubricant forms a thin film between surfaces, reducing friction and
wear.
• Used in bearings, seals, and sliding components in machinery for continuous
lubrication.
• Offers reduced maintenance, extended component lifespan, and improved
performance in challenging environments.
6. 2. Literature Review
(I). J. Prost et al. 2022, Lifetime assessment of porous journal
bearings using joint time-frequency analysis of real-time sensor
data
•Tribological tests were performed using
a custom-built multiple bearing wear test
rig . The test rig was conceived to run
simultaneously five identical tribo tests .
•Constant specific bearing load of 3 MPa
(25 kg/245 N load) and varying speed
within a range of +20 to -20 rpm at 0.1 Hz
frequency.
•Tests conducted at room temperature,
100°C, and 160°C.
•Tests stopped if motor torque exceeded
0.8 Nm or when at least three bearings
failed.
•Custom-fitted plain journal bearings
(PJB) made of bronze and iron-based
materials were used.
•Bearings: External diameter 15.6 mm,
length 11 mm, bore diameter 8.033 ±
0.01 mm.
Fig 1: Experimental Setup (3)
7. Cont`d
Fig. 2. Friction curves of the various material–lubricant pairings at (a) RT, (b)
100∘C and (c) 160∘C. (3)
8. (II). A multiscale-approach for wear prediction in journal bearing systems
from wearing-in towards steady-state wear
•Conducted multiple experiments with cycle
counts of 30,000, 360,000, and 720,000.
•Stationary load: 2250 N, speed: 250 min^-1,
each experiment performed twice with new
shaft sleeve and bearing setups.
•Radial load applied using a flexible load unit on
the bearing housing.
•Full radial load applied after reaching stationary
drive speed to minimize wear during startup.
•Friction gauge directly connected to the bearing
housing used to measure frictional force.
•Continuous measurement of drive speed, radial
load, friction force, inlet and bearing
temperatures during experiments.
•Bearing coefficient of friction (CoF) calculated
from measured friction torque (MF), using CoF =
MF / (FR * r), where FR is the radial load and r is
the bearing radius.
•Circumferentially positioned heating cartridges
in the journal bearing housing used to mitigate
local heating effects.
Fig 3: Experimental Setup (4)
9. Cont`d
Fig 4: Experimental results: CoF, oil inlet and bearing temperature during
the first 10000 cycles. (4)
Fig 5: Simulation results: evolution of CoF, gap height, maximum
asperity and hydrodynamic contact pressure. (4)
10. (III) Yi Zhu et al 2018, Material characterization and lubricating behaviors of
porous stainless steel fabricated by selective laser melting
•Pin-on-disc machine used to study pores' impact
on SLM pin lubrication.
•Discs made of 38CrMoAl with hardened surfaces
(1000 HV) polished to Ra=0.05 μm.
•SLM pins manually polished to Ra=0.1 μm,
excluding pores, for uniform comparison.
•Rotation speeds ranged from 200 to 900 rpm,
translating to sliding speeds of 0.34 to 1.51 m/s.
•Applied loads of 3 N and 6 N resulted in maximum
Hertzian contact pressures of 0.96 and 1.2 GPa,
respectively.
Fig 6 : Experimental Setup (5)
11. Cont`d
Fig.7. Results of coefficients of friction
under 3 N. (5)
Fig.8. Results of coefficients of
friction under 6 N. (5)
12. (IV) Xiaowen Qi et al 2014, Effects of weft density on the friction and wear
properties of self-lubricating fabric liners for journal bearings under heavy
load conditions
.
•Fabrication involved weaving using an Y200S Electronic Sample Loom,
producing two liner types: a conventional plain weave and an HZ-1
reinforced liner in a one-third broken twill weave. Both had a warp
density of 290 roots per 10 cm and a weft density varying between 200-
450 roots per 10 cm with intervals of 50 roots per 10 cm.
•After soaking in acetone for 24 hours and boiling in distilled water for 15
minutes, the fabric underwent drying at 80°C for an hour and was then
soaked in phenolic-acetal resin. Ultrasonic cleaning for 3 hours followed
by rolling with a glass rod to remove bubbles ensured full resin saturation
and uniform fabric coverage. A final drying at 110°C for an hour
completed the fabric liner.
Fig. 9. Structure diagrams of the tester. (6)
13. Cont`d
Fig 10. Influence ofweft density on friction coefficient off a self-
lubricating liner underload of (a)110MPa,(b)179MPaand(c)248MPa. (6)
Fig. 11. Influence of weft density on wear rate off self-lubricating liner
underload of (a)110MPa,(b)179MPaand(c)248MPa. (6)
14. Research Gap
• Exploring advanced materials for porous bearings,
considering durability, wear resistance, and thermal
stability, is essential. Research that delves into novel
material compositions or surface treatments to enhance
bearing longevity is a notable gap.
• Investigating the intricacies of fluid-film lubrication
within porous bearings, especially at micro or nano
scales, to optimize lubrication efficiency and minimize
energy losses is an area requiring further exploration.
15. Future Plan
• I hope to investigate further porous material available for
making journal bearing
• Also the heat treatment process can be applied to enhance
properties of that bearing
16. Refrences
1. https://en.wikipedia.org/wiki/Bearing_(mechanical)
2. https://en.wikipedia.org/wiki/Porous_medium#:~:text=In%20materials%20science%2C%20
a%20porous,fluid%20(liquid%20or%20gas)
3. J. Prost, G. Boidi, M. Varga, G. Vorlaufer, S.J. Eder, Lifetime assessment of porous journal
bearings using joint time-frequency analysis of real-time sensor data Tribology International
169 (2022) 107488
4. Florian König⁎, Achraf Ouald Chaib, Georg Jacobs, Christopher Sous, A multiscale-approach
for wear prediction in journal bearing systems – from wearing-in towards steady-state wear ,
Wear 426–427 (2019) 1203–1211
5. Yi Zhua,⁎, Guoliang Lina, M.M. Khonsarib, Junhui Zhanga, Huayong Yanga Material
characterization and lubricating behaviors of porous stainless steel fabricated by selective
laser melting Journal of Materials Processing Tech. 262 (2018) 41–52
6. XiaowenQi a,n, JianMaa, ZhiningJia b,n, YulinYang a, HaibiGao Effects of weft density on the
friction and wear properties of self-lubricating fabric liners for journal bearings under heavy
load conditions Wear318(2014)124–129
