DOI : 10.17577/IJERTV4IS100528
- Open Access
- Total Downloads : 318
- Authors : Mr. Harshal Panditrao Deshmukh, Mr. Navneet K. Patil
- Paper ID : IJERTV4IS100528
- Volume & Issue : Volume 04, Issue 10 (October 2015)
- DOI : http://dx.doi.org/10.17577/IJERTV4IS100528
- Published (First Online): 24-10-2015
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Experimentation and Analysis of Three Different Compositions of Semi-Metallic Brake Pads for Wear Rate under Dry Friction Condition
Harshal P. Deshmukh
M.E. Student
Dept. of Mechanical Engg..
SSBT's college of engineering and technology, Bambhori, jalgaon, Maharashtra, India.
Navneet K. Patil
Associate Prof.
Dept. of Mechanical Engg..
SSBT's college of engineering and technology, Bambhori, jalgaon, Maharashtra, India.
AbstractThis work is a part of curiosity to know actual behavior of brake pad material related to wear under the influence of parameters like velocity of sliding, sliding distance, and last but not the least normal load when the brake pad is subjected to work with dry friction. Brake pads should ensure continuous coefficient of friction, safety and durability. Brake pads in disc brake systems are made of complex composite material; such three compositions are selected for test and study, coded as material I, material II and material III. Detail composition of all three materials are obtained by EDX on scanning electron microscopy machine, experiment is designed by using Taguchi array in design expert 7 software and the test is conducted on pin-on-disc test rig, earlier mentioned parameters are set for three different levels and in optimum possible combination by Taguchi experimentation design array. Wear rate is obtained as a response of experimentation and then further analyzed in design expert software. Parametric relation is developed in the form of equation for each material composition. At the end all three materials are compared on the basis of wear rate and coefficient of friction. As graphical representation is the most user friendly way of interpretation of statistical data, three-dimensional graphs comparing wear rate of all three materials simultaneously under the influence of individual parameters namely load, sliding distance and sliding velocity are given in results. Conclusions of the present work are, as load and sliding distance increases wear rate also increase, and as the velocity of sliding increases wear rate slightly decrease. material composition is the major factor influencing the wear rate of brake pad, as the wear rate of all three material are different which is shown in paper in tabulated form. The increase in percentage of carbon (in graphite form) increases the wear resistance.
KeywordsWear rate; Wear analysis; Brake pads; Design Expert, Material composition
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INTRODUCTION
A brake can stop or slow down a moving vehicle by converting kinetic energy into friction heat. A Disc brake is sliding friction couple made of rotor (disc) connected to the wheel and a stator on which the friction material (say brake pad) is mounted. The friction causes wear of Brake pads. The brake pad is characterized by the frictional behavior brake pads are always subjected to wear. The result can be
dangerous if the brake fails. Therefore, the material used for brake pad is very important part of a braking system.
Brake pad material should have (1) High Coefficient of friction (2) Good thermal conductivity (3) minimum wear rate (4) good wear resistance when subjected to heavy loads and high speeds [1].
The Disc against which a brake pad slides can be Ferrous or Nonferrous, two have different effects of wear rate of brake pads [2]. To find the wear rate characteristics of different compositions of brake pad materials sliding against the same disc, a pin-on-disc setup is ideal. Pins of all three Material compositions are made and tested by designing an experiment using Taguchi array [3] .Many resins and composites are used now days to meet the requirements of brake pad materials [5]. To have better wear resistance characteristics Aluminium based metal composites are used they shows better tribological properties [6].
The following work in this paper concentrates more on the material composition for brake pad and there wear rates. Pin on disc setup is used for performing experimental work to obtain wear rate, the result is analyzed using design expert 7 software, and the relation between various tests parameters are found in terms of a mathematical equation. the basic trend of effects of parameter like Normal load, Velocity of sliding and Sliding Distance on wear rate is interpreted in graphical form finally a comparison between three material compositions is made.
-
METHODOLOGY
-
Selection of parameters
For the three composite materials to be compared on the basis of wear rate on pin-on-disc setup three parameters are selected for the experiment, these three have direct effect on wear.
-
Normal load
-
Sliding velocity
-
Sliding distance
And the working condition is considered as dry sliding, Temperature is not considered as a factor because the brake pad material is made by powder metallurgy and the curing temperature for binding is about 2300C, the maximum temperature reached during testing is below curing temperature.
-
-
Design of test runs
The To ensure the optimum interaction of all the parameters L9 (3^4) Method of Taguchi Orthogonal array is used which have nine test runs, 3 levels of factors, and maximum 4 factors, we identified 3 factors.
TABLE I. FACTORS AND THEIR LEVELS
Level
Low
Medium
High
Load (kg)
2
4
6
Disc Speed (RPM)
500
800
1100
Sliding distance
(km)
1.5
2.5
3.5
If the parameter given in Table I are put in Design expert software it will generate a following Run sheet of parameters for pin-on-disc setup shown in Table II which can be further utilized as Observation table to note wear rate as response.
TABLE II. LAYOUT OF L9 ORTHOGONAL ARRAY FOR EXPERIMENTATIONS
Run
Load (kg)
Disc speed (rpm)
Sliding distance (km)
1
2
500
1.5
2
2
800
2.5
3
2
1100
3.5
4
4
500
2.5
5
4
800
3.5
6
4
1100
1.5
7
6
500
3.5
8
6
800
1.5
9
6
1100
2.5
-
Selection of material
The experimentation is carried out on the pin on disc test rig. To start the experimental work first three different materials are selected and coded as Material I, Material II, and Material III. The detail composition of these three materials are given in tabulated form in Table III to TableV, the composition is tested by EDX on SEM machine
TABLE III. DETAIL COMPOSITION OF MATERIAL I
Element
Net Counts
Net Counts
Error
Weight
%
Atom %
C
225
+/- 26
13.3
35.13
O
1342
+/- 100
13.81
26.72
Si
2427
+/- 113
5.76
6.35
P
373
+/- 67
0.98
0.98
S
2607
+/- 251
6.91
6.67
S
0
+/- 17
—
—
Ca
342
+/- 51
1.14
0.88
Ca
0
+/- 44
—
—
Fe
492
+/- 89
4.21
2.33
Fe
382
+/- 118
—
—
Cu
1836
+/- 110
32.47
15.81
Cu
11590
+/- 172
—
—
Mo
1096
+/- 418
3.87
1.25
Mo
81
+/- 16
—
—
Ba
2309
+/- 162
17.23
3.88
Ba
0
+/- 190
—
—
Total
100.00
100.00
TABLE IV. DETAIL COMPOSITION OF MATERIAL II
Element
Net Counts
Net Counts
Error
Weight %
Atom %
C
206
+/- 27
20.91
32.63
O
1968
+/- 73
45.06
52.78
Mg
272
+/- 38
1.33
1.03
Al
771
+/- 44
3.60
2.50
Si
1678
+/- 84
7.38
4.93
S
748
+/- 144
4.08
2.39
S
0
0
—
—
Ca
365
+/- 68
2.75
1.29
Ca
0
+/- 40
—
—
Fe
39
+/- 19
0.81
0.27
Fe
0
+/- 31
—
—
Cu
1
+/- 12
0.06
0.02
Cu
292
+/- 46
—
—
Mo
608
+/- 238
4.42
0.86
Mo
140
+/- 17
—
—
Ba
553
+/- 85
9.59
1.31
Ba
0
+/- 92
—
—
Total
100.00
100.00
TABLE V. DETAIL COMPOSITION OF MATERIAL III
Element
Net Counts
Net Counts
Error
Weight %
Atom %
C
392
+/- 46
27.34
43.76
O
1536
+/- 94
30.69
36.88
Na
232
+/- 35
1.72
1.44
Mg
451
+/- 45
1.74
1.38
Al
864
+/- 99
3.14
2.24
Si
1411
+/- 97
4.75
3.25
S
1057
+/- 84
4.28
2.57
S
0
0
—
—
K
92
+/- 32
0.45
0.22
K
0
+/- 75
—
—
Ca
1319
+/- 88
7.30
3.50
Ca
0
+/- 52
—
—
Fe
690
+/- 66
10.63
3.66
Fe
1018
+/- 73
—
—
Ba
622
+/- 89
7.98
1.12
Ba
0
+/- 42
—
—
Total
100.00
100.00
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Fabrication of Pins
Three pins are made respectively from brake pad materials material I, material II, and material III shown in Fig1.
Fig. 2. Pin on disc Test-Rig
Run
Load (kg)
Disc speed (rpm)
Time (min)
1
2
500
11.943
2
2
800
12.44
3
2
1100
12.666
4
4
500
19.904
5
4
800
17.416
6
4
1100
5.4285
7
6
500
27.866
8
6
800
7.4642
9
6
1100
9.0475
TABLE VI. FINAL TEST RUN DESIGN
-
Test Setup
Fig. 1. Pins for Testing
-
-
TESTING
Experiments are conducted as per the design matrix Table IV and response is recorded in terms of wear by weight loss method. Weight of pin before run and weight of pin after run is noted and calculated to obtain wear rate. Weighing scale with minimum capacity of 10 mg is used for the same. Response parameters are different for each material composition under study. The value of wear rate
Standard pin on disc test set up is used for the
experiment on the specially made pins. The photo of test setup is shown on Fig 2.
Layout of L9 orthogonal array for experimentation is shown in Table II, the arrangement to set sliding distance is not provided on test setup instead the time of run can be calculated and can be monitored using stopwatch, the final test run and parameter combination is shown in Table VI.
and the parameter matrix of Table II are put in design expert software for further analysis.
For the analysis and to find correlation all factors should be in same unit therefoe while filing the data in software Disc speed and Run time is converted in Sliding Velocity (m/s) and Sliding Distance (Km) as shown in Table VII.
Run
Load (kg)
Sliding Velocity (m/s)
Sliding Distance (m)
1
2
2.09
1500.00
2
2
3.35
2500.00
3
2
4.61
3500.00
4
4
2.09
2500.00
5
4
3.35
3500.00
6
4
4.61
1500.00
7
6
2.09
3500.00
8
6
3.35
1500.00
9
6
4.61
2500.00
TABLE VII. FINAL TEST RUN DATA FOR SOFTWARE
Design-Expert® Software Wear rate*10^-6 gm/m
X1 = C: Sliding Velocity X2 = A: Material
Actual Factors B: Load = 6
D: Sliding Distance = 3.5
55
Wear rate*10^-6 gm/m
43.75
-
RESULTS AND DISCUSSION
32.5
21.25
41.600533
3.34933
C: Sliding Velocity
2.09333
II
III
I
A: Material
Analysis of Variance (ANOVA) for Wear Rate is done for all three Material compositions and checked if the model is significant or not, when all models were significant the following list of effects showing percentage contribution of various parameters is shown in Fig VIII.
TABLE VIII. % CONTRIBUTION OF THREE FACTORS AND THEIR INTERACTIONS, FOR WEAR RATE (FROM EFFECT LIST)
Fig. 4. Wear rate v/s Sliding velocity
Design-Expert® Software Wear rate*10^-6 gm/m
X1 = D: Sliding Distance X2 = A: Material
Actual Factors 55
B: Load = 6
Wear rate*10^-6 gm/m
C: Sliding Velocity = 2.09333
42
29
% CONTRIBUTION
FACTORS
Material I
Material II
Material III
A:Load
19.5854
49.42412
45.93967
B:Sliding
Velocity
34.51224
12.24373
9.836818
C: Sliding
distance
26.96055
10.20689
15.66722
AB
2.007044
22.16683
22.56058
AC
2.234055
5.391931
5.748114
BC
14.70071
0.566495
0.247606
16
3 III
3500
2500
II
A: Material
D: Sliding Distanc
I 1500
Result graphs are obtained after wear rate analysis in Design -Expert software.
Design-Expert® Software Wear rate*10^-6 gm/m X1 = B: Load
X2 = A: Material
Fig. 5. Wear rate v/s Sliding Distance
-
It is clearly seen from Fig. 3 to Fig. 5, that as load and sliding distance increases wear rate of all three brake pad materials also increases whereas velocity of sliding increases wear of all three brake pad materials decreases.
Actual Factors
C: Disc Speed*100 = 5 D: Sliding Distance = 3.5
55
Wear rate*10^-6 gm/m
42.5
30
17.5
-
It is observed from Table IX that the wear of material-III is less than material I and II and Material I which have 32.47 % of Cu by weight and 13.63 % Carbon has highest wear rate and the percentage of Carbon in Material II is 20.91% and in material III is 27.34% by weight which show lesser wear rates respectively.
5 III 6
II
A: Material
4
I 2 B: Load
Fig. 3. Wear rate v/s Load
TABLE IX. COMPARATIVE WEAR DATA OF ALL MATERIAL
Sr. No
Material
Total Wear rate in
(gm/m)
Average Coefficient of friction
()
1
Material I
23.1×10-5
0.290468
2
Material II
17.8×10-5
0.302978
3
Material III
13.4×10-5
0.329993
-
Following correlations are obtained for three materials.
-
For material I
-
Wear rate × 10-06 gm. /m = – 67.91379 +
10.95469 × Load + 14.17233 ×
Sliding Velocity + 0.034911 × Sliding Distance -1.18074 × Load × Sliding Velocity -1.56463 × 10-03 × Load × Sliding Distance – 6.39107×10-03 × Sliding Velocity × Sliding Distance.
-
-
CONCLUSION
-
Wear rate of brake pads increase with the increase in normal load
-
Wear rate of brake pads decreases with increase in sliding velocity
-
Wear rate of brake pads increases with increase in the sliding distance.
-
Carbon in brake material composite is in the graphite form and graphite acts as a solid lubricant. Increase in percentage of carbon in composition may lead to increase in wear resistance. Material I which has
13.63 % Carbon has highest wear rate amongst three. The percentage of Carbon in Material II is 20.91% and in material III is 27.34% by weight, and the
wear rates decreases with increase in % of C respectively.
-
To satisfy all the requirements of brake pad materials. Brake pad is made of complex composition to have minimum wear rate amongst family of materials. Since the highest total wear rate amongst three is 23.1×10-5 gm/m which ensure great durability.
-
For material II
Wear rate × 10-06 gm. /m = -26.12386 + 9.71656
× Load + 12.12859 × Sliding Velocity -8.61709 × 10-04 × Sliding Distance -3.18471 × Load × Sliding Velocity + 1.97279 × 10-03 × Load × Sliding Distance – 1.01823 × 10-03 × Sliding Velocity × Sliding Distance.
-
For material III
-
Wear rate × 10-06 gm. /m = -33.29857 +10.09749×
Load +12.43194× Sliding Velocity – 1.49658× 10-03 ×Sliding Distance – 3.41219× Load ×Sliding Velocity
+2.16327 × 10-03 × Load × Sliding Distance – 7.14939× 10-04 × Sliding Velocity × Sliding Distance.
ACKNOWLEDGMENT
For the valuable support and great co-operation to perform my experimental work, I would like to thanks Department of Mechanical Engg., SSVPs B. S. Deore College of Engineering, Dhule.
REFERENCES
-
A. N. Tiwari, R Ramakrishnan Composite material for automotive brakes, Powder Metallurgy Processing for Automotive, Electrical Electronic and Engineering Industry, New age international (P) Ltd, ISBN81-224-2030-3, 2007, pp. 86-102.
-
M. Ramesh, T. Karthikeyan, R. Arun, C. Kumaari, P. Krishnakumar and M. Mohankumar, effects of applied pressure on the wear behavior of brake lining sliding against ferrous and nonferrous disc, International Journal of Advanced Mechanical Engineering, ISSN 2250-3234 Volume 4, Number 3 (2014), pp. 285-290.
-
Deepak Bagale , Sanjay Shekhawat , Jitendra Chaudhari, Wear analysis of polytetrafluoroethylene and its composites under dry conditions using design-expert, International Journal of Scientific and Research Publications, Volume 3, Issue 1, January 2013 1 ISSN 2250-3153.
-
Dr. Ahmet Akkus, Mukadder Yein, Research on Wear Rate and Mechanical Properties of Brake Sabots (Shoes) Used in Railway Rolling Stocks, International Journal of Applied Science and Technology Vol- 4, No- 7; December 2014,pp. 76-84.
-
P.V. Gurunath, J. Bijwe, Friction and wear studies on brake-pa materials, Wear 263 (2007) 12121219.
-
Mohammad. Asif, Tribo-evaluation of Aluminium Based Metal Matrix Composites Used for Automobile Brake Pad Applications based on newly developed resin, Plastic and Polymer Technology (PAPT) Volume 1 Issue 1, December 2012, pp.9-14.
-
G. Cueva , A. Sinatora , W.L. Guesser , A.P. Tschiptschin, Wear resistance of cast irons used in brake disc rotors, Wear 255 (2003),
pp. 12561260.
-
R.J. Talib, M.A.B. Azimah, J. Yuslina, S.M. Arif and K.Ramlan, Analysis on the hardness characteristics of semi-metallic friction materials, Solid State Science and Technology, Vol. 16, No 1 (2008), ISSN 0128-7389, pp. 124-129.