b Individual Lab Assignment Sem12015 016 to AAbass

8/19/2019 b Individual Lab Assignment Sem12015 016 to AAbass

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FACULTY OF ENGINEERING,MECHANICAL DEPARTMENTEngin eer ing Tribology - 15MECH02H

LAB SHEET

SEMESTER 1 (2015/2016)

Wear & Frict ionFriction Coefficient + Wear Rate

Measurements

Venue: Material Lab, FoE- Building_A

Note : Students are advised to read through this lab sheet before coming to the lab.

Students Name / ID: …………………………………..…………… /………….………

Date of conducting experiment: …………………………………..…………

Submission date:……..../……… / 2015

Students Comments

and Suggestions forimprovement

…………..……………………………………………………………..

……………………………………………………………..…………

………………………………………………

Module Leader / Prof. Nabil EL-Tayeb



Fr iction Coeffi cient and Wear Rate Measurements 1Engineering Tribology, (15MECH02H), 1

ST Semester 2015/016

Prof. Nabil EL-Tayeb ____________________________________________________Tribo-Test / 1

Friction coefficient& Wear Rate

Experiment Overview and main Objectives

Tribology is an important branch in machine design, which concerns the interaction at the contact

between two solids in relative motion. This interaction causes dissipation of energy (due to friction)and changes in the dimensions of mating parts (due to wear) and consequently impairs the accuracy of

machine.

Several objectives and scopes should be accomplished by the end of this experiment. These are:

(A) To study the common wear techniques and vari ous test apparatus

It is vital for student to have visualization on commonly used friction and wear test techniques,

Fig.1, and some of the apparatus, which have been developed for fundamental study of wear and

friction.

(B) To understand the procedure of the wear and fr iction assessments

It is also important for student to look into the general assessments of wear and friction. This

includes the Tribo-test system, operating variables of the system, Tribo- characteristics; methods of

determine wear rates and friction coefficients, and the factors that affecting friction and wear.

(C) To establish a calibration set up for measur ing the kinetic f r iction forces

This will necessitate setting up a calibration procedure to measure the bending distance of load

lever for student to look into the general assessments of wear and friction. This

Specific objectivesThis experiment is mainly to measure the Tribological properties, specifically the friction coefficientand wear rate of some materials under different test conditions, namely, test duration, sliding distance,

applied normal load, and sliding velocity.

Requirements:

1. Perform Tribo-tests and determine friction coefficient and wear rate;

2. Evaluate and characterise features of worn surfaces in view of

experimental data obtained from Tribo tests;

3. Write a technical report, correlating data obtained from Tribo tests to

friction and wear theories.

Submission deadline two weeks from conducting the Tribo-test






(A) Common techniques of friction and wear tests

Fig.1 Common techniques for wear tests

Experimental Apparatus (Tribo-Test Machines)

Fig.2 Friction and Wear Test Machine, Block-on-Disc[ Designed by Dr. Nabil EL-Tayeb and fabricated by FYP/2003, FET ]

Fig.3 Tribo-Test Machine, Pin-on-Disc Fig.4 Tribo-Test Machine, Pin-on-Ring[Designed by Dr. Nabil EL-Tayeb and Fabricated by TS Automation SDN BHD, (2003) FET ]






Required EquipmentsThe equipments required to run the tests are:

a) Weight scale, F ig.2.5: This equipment is required to measure the weight of the specimen before

and after each test. The scale can measure up to two decimal points in gram (gm).

Fig.5 Weight scale Fig.6 Velocity measuring device

(Tachometer) b) Velocity Measur ing Device, Fi g.2.6: This device is used to calibrate the rotational speed rpm (or

sliding velocity m/min or ft/min) of the rotating counterface.

c) Dead weight, F ig.7: Different dead weights can be used to set up an applied normal load on thespecimen.

Fig.7 Dead weights

d) Stopwatch F ig.2.8: Stopwatch is needed for timing purpose. This is to set up the test duration.

Fig.2.8 Stopwatche) Thermometer: Thermometer is to be used to measure the room temperature where the

experiments are to be conducted.






(B) Experimental Procedures

Wear rate (Wr) and Friction Coefficient ( ) Measurements

Three different experiments that can be conducted which are quite similar to each other.

Procedure of Experiment for (Wr and against Test Duration / Sliding Distance)

1. Measure the weight of the specimen and record the

weight in the attached Table.

2. Clamp the specimen to the appropriate holder, andcheck the levelness of the load lever, make sure the

specimen face is in intimate contact with the

counterface surface.

3. Select the normal load and apply.4. Record the room temperature using thermometer.

5. Set the rotational speed of the counterface;6. Connect the digital multimeter7. Set the time (using the stopwatch) and switch on the test machine.

8. Monitor the rotational speed of the counterface frequently during the experiment.

9. Record the bending distance of the load lever (friction force) and record the value in the Table.10. Stop the test machine after the prescribed time.

11. Release the specimen from the adapter, measure its weight, and record the value in the Table.

12. Repeat the test for different durations while rotational speed and normal load are fixed.

13. Plot the results as wear rate and Friction coefficient vs sliding distance.14. Discuss the effects of sliding distance on wear rate and friction coefficient.

15. Take photos for each activity you conduct during the experiment

Simi lar procedure can be fol lowed to study the effect of Normal L oad and Sli ding Velocity on

the Wear r ate and F ri ction coeff icient






(C) Calibration Set-up and procedureThe friction force is measured in terms of bending distance of the load lever. Therefore, it is necessary

to calibrate the bending distance indicated by the digital multimeter attached to the test machine. Thecalibration procedure, using the system shown in Fig.9, will be discussed during the lab session. Acalibration chart has to be produced to give the relationship between the friction force in Newton and

the bending distance in mV, as shown in Fig.10.

Fig.9 Calibration arrangement system

Applied weight,

kgx9.81= (N)

Measured (mV)

Calibration Chart

y = 0.7205x + 0.3846

0

2

4

6

8

10

12

14

16

18

20

0 5 10 15 20 25 30

Friction Force (N)

B e n d i n g D i s t a n c e ,

X ( m v )

Fig.10 Calibration Chart

Documents

b Individual Lab Assignment Sem12015 016 to AAbass