EXPERIMENTAL ANALYSIS OF COMPOSITE BRAKE LININGS

International Journal of Mechanical and Production Engineering Research and Development (IJMPERD) ISSN (P): 2249–6890; ISSN (E): 2249–8001 Vol. 10, Issue 3, Jun 2020, 1119-1130 © TJPR Pvt. Ltd.

EXPERIMENTAL ANALYSIS OF COMPOSITE BRAKE LININGS Dr. BVS RAO & P. ANJANI DEVI Assistant Professor, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabd, India ABSTRACT Fiber reinforced polymers are promising materials for the applications in modern vehicles. Materials used for brake pads should have stable and reliable frictional and wear properties under varying conditions of load, velocity, temperature, and high durability. The main aim of this work is to replace the existing conventional asbestos based brake linings by fiber reinforced polymers. The frictional composite is developed by combining Rubber scrap (tire peels) (used as reinforced material), Graphite (friction modifier), Phenolic resin (binder), aluminum oxide (abrasive ); and the efficiency, performance is tested and compared with the existing materials in brake linings.

KEYWORDS: Fiber Reinforced Polymers, Brake pads & Brake Linings

Received: May 25, 2020; Accepted: Jun 16, 2020; Published: Jun 24, 2020; Paper Id.: IJMPERDJUN202096

Brake is a mechanical device is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion by means of friction. The purpose of friction brakes is to decelerate a vehicle by transforming the kinetic energy of the vehicle to heat, via friction, and dissipating that heat to the surroundings. Figure1 illustrates the basic structure of the two different types of braking system that are available in the vehicles nowadays. The disc brake is most widely used over the drum brake as they provide very efficient braking without any slipping or sliding. Brake linings, a

Original Article

1. INTRODUCTION

frictional material attached to a brake shoe, are composed of a relatively soft but tough and heat-resistant material with a high coefficient of dynamic friction typically mounted to a solid metal backing using high-temperature adhesives or rivets. The dynamic friction coefficient "µ" for most standard brake pads is usually in the range of 0.35 to 0.42. Figure2 shows the components of the drum brake Asbestos has been used as reinforcement material in brake lining production because of it’s good physical and tribological properties. Recent studies have shown that asbestos is hazardous resulting in the need for an alternative. K.K. Ikpambese [1] et.al. prepared brake pad material using ecofriendly palm kernel fibers (PKFs) with CaCO3, graphite and Al2O3 as other constituents. Epoxy resin was used as binder. Composition of 40% epoxyresin, 10% palm wastes, 6% Al2O3, 29% graphite, and 15% calcium carbonate gave better properties than other composition. Results shown that PKF can be suitable for replacement of asbestos brake pads with epoxy resin as a binder. Idris et-al[2] investigated the Morphology, physical, mechanical and wear properties of the brake pad fabricated with banana peels waste and phenolic resin varying from 5 to 30wt% with interval of 5wt%. The results shown that compressive strength, hardness and specific gravity of the produced samples were seen to be increasing with increased in wt% resin addition, while the oil soak, water soak, wear rate and percentage charred decreased as wt% resin increased. The result of this research indicates that banana peels particles can be effectively used as a replacement for asbestos in brake pad manufacture.

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Figure 1: Types of Braking Systems.

Figure 2: Drum Brake System.

Graham L. Donne and Peter M. Watson [3] presented the noticeable differences between the friction and wear characteristics of the four gray cast irons. The basic concept of friction and wear characteristics of suitable grade of cast iron has been taken from this literature and incorporated in this work.

Poh Wah lee[4] et.al. studied the friction and wear performance of Cu-free and Sb-free environment friendly automotive brake friction materials with natural hemp fibers and geo polymers as a fraction replacement of synthetic Kevlar fibers and phenol resins, respectively. The geopolymer in the brake materials reduced the amount of phenol resin, which will release volatile organic compounds (VOCs) when pads are subjected to temperatures higher than 300 0C. The Dynamometer results shown that the modified samples had better performance when compared to the T-baseline (Cu, Sb based). However, the modified samples exhibit higher wear rate than the T-baseline. Gueva et.al. [5] discussed about the wear resistance of three different types of gray cast iron (gray iron grade 250, high-carbon gray iron and titanium alloyed gray iron), used in the brake rotors and compared them with the results obtained with a compact graphite iron(CGI). This work was very useful in choosing material for the current work.

2. MATERIALS USED IN FABRICATION OF COMPOSITE BRAKE LINING 2.1 Materials used The four materials used for the production of brake lining are reinforced material (fibres of coconut, jute etc.), friction modifier (graphite ), binder ( phenolic resin ), and abrasive ( aluminum oxide ).

Table1: Materials used in the fabrication

Table 1 illustrates the types of materials that are used for the formation of composite materials. Based on their individual mechanical properties, the so formed composite material inherit different mechanical properties which are advantageous and result in efficient braking.

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Figure3: Product Structure.

Figure4: Development of Composite Brake Lining.

Figure 3 shows the product structure of a brake lining of a basic disc brake. Friction material structure plays a key role in implementing an efficient brake to a system 2.2 Material Preparation 

The coconut and jute fibers are used as reinforced material. The fibers were cut into pieces and washed thoroughly to get rid of dirt which may have possibly combined with the rubber tire powder. The tire pieces were dried in the sun for 1 week and grounded into fine powder using a bench grinding machine. The powder was sieved using a sieve size ≤100 μm to eliminate any fibers that may be present.

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Graphite used in this study as friction modifier used was obtained from used 1.5V dry cell batteries. The graphite rod was extracted from the used batteries and crushed to smaller sizes using a hammer. It was then pounded using a mortar and pestle and sieved using sieves size ≤100 μm.

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The phenolic resin used as binder in this study was phenol formaldehyde.

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The aluminum oxide is used as abrasive.

Figure 4 illustrates different forms of the materials that are used in formation of a composite material.

2.3 Specimen Composition Specimen are classified based on their compositions. Five basic compositions have been chosen according to the requirement of optimum values of friction and wear rate.

Table 2: Compositions of the Casting Polyester Resin

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Table 2 illustrates the different compositions of the Casting Polyester Resin.Al2O3, Graphite, Coconut & jute fibers, and Silica in weight percentages that are used in the preparation of 5 individual sample specimens.

3. METHODOLOGY The formulation of brake lining sample consists of a series of operations including mixing, cold and hot pressing, cooling, post-curing, and finishing which is known as Resin Transfer moulding or Resin Casting . This yield increased laminate compression, a high glass-to-resin ratio, and outstanding strength-to-weight characteristics.

Figure 5: CI Cylindrical Die and Specimen.

Figure 6: Proportional Compositions of Coconut Fibers, Graphite and Al2O3 for Specimen 1.

Figure 5 shows the lathe machined CI cylindrical die with a through hole of 10mm diameter drilled for 28mm long and the composite material taken out after 24 hours of curing from the hole.

Reinforcement mat is placed in the mold, which is then closed and clamped. Catalyzed, low-viscosity resin is pumped in under pressure, displacing the air and venting it at the edges, until the mold is filled.. In the production of the friction lining, the weights of the phenol-formaldehyde resin, friction modifier (graphite), and abrasive (aluminum oxide) are taken according to those in commercial brake linings available in the current market except the fibers, which are considered to cause great impact on the results of our experimental analysis. Phenolic resin was poured into a container, followed by the addition of small quantity of Sulphuric Acid (catalyst) and mixed thoroughly. The required quantity of fibers, Aluminum Oxide and Graphite powders were poured into a separate container and mixed thoroughly manually. The mixture was poured into the container holding the resin and further stirred thoroughly to obtain homogeneous mixture. The mixtures were then placed in a mold of size ø10 x 28 mm. The compression and curing of the composite samples were carried. Figure6 illustrates the weights of different materials (fibers, graphite, Al2O3) taken into mixture of the resin for the formation of specimen 1.

4. TESTING Of BRAKE LINING 4.1 Wear and Friction Test The brake lining material is cured into a cylindrical block and Wear and Friction tests are performed using ‘Pin On Disc: Friction And Wear Test Rig’.

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The Pin on Disc: Friction & Wear Test Rig determines the tribological characteristics materials under varied loads & temperatures under dry & lubricated conditions with different environmental conditions. Figure 7 shows the specifications of the apparatus.

This test rig not only helps us to identify the wear and friction of the brake lining, but also helps in identifying the frictional force and the temperature of the brake lining. There are certain amount of inputs and conditions to be given to the machine in order to run the test. They are mentioned below Figure 7: Specification of the Pin on Disc Friction and Wear Test Rig. For all the brake lining samples, tests were conducted without altering any input values. 

Dimension of specimen = ø10 x 28mm

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Pressure = 56.08 KN/m 2

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Normal load = (Pressure/Area) = (56.08 KN/m 2 /Π*(5.5) 2 ) = 5 N

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Speed of disc = 330 rpm

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Test time = 10 minutes Table 3: Inputs Provided to the Test Rig in or to Conduct the Test

Table 3. illustrates various inputs (sliding distance of the friction lining contact surface, load applied on the disc, speed of the disc), provided to the test rig in or to conduct the test 4.2 Oil and Water Absorption Test Specimen of 90 mm dimension were prepared from each samples of formulated composite brake lining material. Each sample was dried in an oven to constant weight. The initial weight of each specimen was recorded using digital weighing balance. The specimen were immersed in distilled water and brake fluid (oil), respectively, at room temperature for a period of 3 days. Every 24 hours, they were taken out and the surface water and oil wiped off with a cloth and weighed.

The new weight of each sample during the routine removal was recorded. The weighing was done within 30s in order to avoid any error that may occur as a result of evaporation. The weight change in oil and water were calculated by subtracting initial weight from the new weight after 72 hours of soak. The percentage water or oil absorption by weight after 24 hours was determined using equations

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Table 4: Percentage of Water Absorption

Table 4 illustrates the amount of water absorbed for all the five samples after keeping them dipped in water for 24 hours. The specimen 5 shows minimum water absorption when compared to the other specimens.

5. Modulus of Short Fibers Using the Halpin-Tsai equations the moduli of aligned short-fiber composites is calculated.

5.1 Jute Fiber: Table 5 illustrates the mechanical properties of jute fiber viz. Young’s Modulus and shear modulus calculated using Halpin-Tsai equation Table 5: Mechanical Properties of JUTE Fiber

5.2 Coconut Fiber: Table 6 illustrates the mechanical properties of coconut fiber viz. Young’s Modulus and shear modulus calculated using Halpin-Tsai equation Table 6: Mechanical properties of Coconut Fiber

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5.3 Density of brake lining: Table 7 illustrate the density of all the specimens in g/cm3 calculated using Rule of mixtures Table 7: Density of all the Specimens

6. WEAR RATE CALCULATION BY WEIGHT DIFFERENCE The dimension of each specimen was measured using caliper of an accuracy of 0.01mm. The test was conducted by placing each sample clamped in a rigid position along the disk of the grinding machine. The weights of the samples before and after the grinding were recorded. The difference in the weight from each sample was calculated as the loss in weight. The same procedure was repeated for a period of 10,20,30,40, and50s for each sample. The wear rate was calculated using the following relation.

Wear Test Calculations for Specimen 1 

Load applied= 5 N

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Time of the wear test = 10 min

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The speed given to the cast iron in RPM = 330 rpm

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The sliding distance = 25 mm

Test Results 

Weight difference of the specimen after the test = 0.07 grams

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Total distance travelled by the specimen on the cast iron disc= 518 m

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Change in volume = weight difference / density (cm 3) = 0.07/1.27== 0.05 cm 3

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Specific Wear rate (cm 3 /Nm.) = (0.055/518)*(1/5) = 21.18*10 -6 cm 3 /N-m

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Table 8: Wear Test Results

Table 8 illustrates the aftermath results of the wear test results of all five specimens featuring weight difference, the distance travelled by the lining, change in volume, and the specific wear rate.

7. RESULTS AND DISCUSSIONS The results of the specimen are based on their performance on the disc in the Pin on Disc machine.

Table 9: Results of the Friction and Wear Test

Table 9 illustrate the results of the friction and wear test conducted on ‘Pin on Disc friction and wear test rig’ which features wear rate, frictional force, coefficient of friction, and average temperature of all five specimens

Specimen 1 Test Results

Specimen 2 Test Results

Specimen 3 Test Results

Specimen 4 Test Results

Specimen 5 Test Result Figure 8: Results of Wear Test of Brake Liming.

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Figure 8 shows the wear rate obtained in the above graph (Specimen 5 test results)is similar to that of the commercial brake linings. The specimen 5 shows the results similar to the regular brake lining standards like, the coefficient of friction is maintained constant throughout the test (rated at 0.51), and the wear rate is also obtained as linearly increasing. This type of composition meets the standards of the commercial brake linings. Hence sample 5 is the best out of all the prepared samples.

The aftermath of practical test included many properties of the specimens of brake linings namely wear rate, coefficient of friction, frictional force, which were mentioned earlier. The mathematical calculations were also found out and compared. The following are the young’s modulus and shear modulus of the specimens calculated using mathematical empirical equations as shown in Table10. Figure 9 illustrates the five sample specimens placed in chronological order.

Table 10: Shear and Young’s Modulus

Table 10 illustrates the shear and young’s modulus values of all five specimens (in GPa)

Figure 9: Composite Brake Lining Specimens.

8. CONCLUSIONS The newly developed linings were investigated by determining its physical, mechanical and tribological properties. Based on properties like density, water absorption, oil absorption, abrasion resistance, coefficient of friction, specific wear rate, young’s modulus and shear modulus, the results obtained for the composite brake linings compared favorably with that of commercial brake pad and other existing ones. Specimen labeled as component 5 gave superior performance over others.

The density, water absorption, oil absorption, frictional force, coefficient of friction, specific wear rate, young’s modulus and shear modulus of the most effective composite specimen (component 5), are 1.22 g/cm 3, 1.188 %, 0.275 %, 5.1 N, 0.51,1.58x10 -6 cm 3 /Nm, 2.19 GPa and 0.8 GPa respectively. From investigation, the results of this work indicated that composite brake lining material can be effectively used as a replacement (for asbestos brake lining materials) in friction lining/ brake pad materials.

REFERENCES 1.

K.K. Ikpambese a, E.A. Lawrence b… Comparative Analysis of Multiple Linear Regression and Artificial Neural Network for Predicting Friction and Wear of Automotive Brake Pads Produced from Palm Kernel Shell Tribology in Industry Vol. 40, No. 4 (2018) 565-573, DOI: 10.24874/ti.2018.40.04.05

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Idris, U.D. et al., Eco-friendly asbestos free brake-pad: Using banana peels. Journal of King Saud University – Engineering Sciences (2013), http://dx.doi.org/10.1016/j.jksues.2013.06.006

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Graham L. Donne and peter M. Watson (1981), “Friction and contact phenomenon of disc brake related to squeal”, PhD thesis, Faculty of science and technology, Uppsala University 1981

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Poh Wah Lee, “ Friction and wear of Cu-free and Sb-free environmental friendly automotive brake materials”, Wear 302(s 1–2):1404–1413 · April 2013.

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Cueva G., Sinatora A., Guesser W.L., Tschiptschin A.P, "Wear Resistance of Cast Irons used in Brake Disc Rotors", 2003. www.elsevier.com/locate/wear"

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Rashid et al, Eco-Friendly Composite for Brake Pads from Agro Waste: A Review, Reference Module in Materials Science and Materials Engineering, 2017 Elsevier Inc.

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Harshvardhan Zula et al, Development Of Friction Pad And Study Of Its Wear Characteristics, International Journal of Mechanical and Production Engineering (IJMPE), pp. 5-8, Volume-5,Issue-2

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10. Aigbodion V.S.et al, Development of Asbestos – free Brake Pad Using Bagasse . Tribology in industry, 32 (1), 45–50.

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12. Aigbodion V. S., Agunsoye J. O. (2010). Bagasse (Sugarcane waste): Non-Asbestos Free Brake Pad Materials. LAP Lambert Academic Publishing, Germany, ISBN 978-3-8433-8194-9.

13. Dagwa I. M., Ibhadode A. O. A. (2006). Determination of Optimum Manufacturing Conditions for Asbestos-free Brake Pad Using Taguchi Method. Nigerian Journal of Engineering Research and Development. Basade Publishing Press Ondo, Nigeria, 5(4), pp. 1–8.

14. Sivarao M., Amarnath M. S., Rizal A. K. (2009). An investigation toward development of economical brake lining wear alert system, IJENS, Vol: 9, No. 9, pp.251-256.

AUTHOR’S PROFILES

Dr BVS Rao is presently working as Assistant Professor in Mechanical Engineering Department of CBIT He has completed his M Tech in Advanced Manufacturing Systems (AMS) from JNTU Hyderabad, and did Ph.D from the same University in the area of Deep Drawing. He has 26 years of experience in Industry and teaching put together. He worked as Production In charge in Hyderabad Precision Manufacturing Pvt Ltd for 2 years, then as Assistant Director in ANDHRA PRADESH PRODUCTIVITY COUNCIL for 7 years. He then entered into teaching and joined CBIT as Assistant professor. He has published 20 Technical Papers in various National and International Journals in the areas of Impact Factor (JCC): 8.8746

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Manufacturing like Metal Forming (Deep Drawing), welding & casting and Industrial engineering etc . He has presented 17 technical papers in National and International conferences, in the same areas as indicated above. His area of interest and research work is in Metal forming, Casting, Welding, CAD/CAM and Industrial Engineering. He got Best papers, in the National Conference at AVC College of Engineering, Mayiladuthurai (TN), and at the National Conference On Advances In Mechanical Engineering held at CBIT, in 2013.

Mrs. P. Anjani Devi is presently working as Assistant Professor in Mechanical Engineering Department of CBIT. She is currently pursuing her Ph.D in the area of Composite Materials from JNTU Hyderabad. She has 10 years of experience in teaching. Her areas of interest include Composite materials, CAD/CAM, Additive Manufacturing .

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