This project is a continuation of a previous research study on light rail brake pad material by a previous student. The main goal of the project is to provide specific data on the characterization of materials currently used in Light Rail Transit brake pads. 19 Figure 3.8.2: STAR brake pad main parts removed from rear plate 19 Figure 3.9: Impact test location development 20 Figure 3.10: Impact test Location on STAR LRT brake pad 20 Figure 3.11: Impact test Location on PUTRA LRT brake pad 21 .
LIST OF APPENDICES
ASTM EDX
INTRODUCTION
BACKGROUND OF STUDY
PROBLEM STATEMENT
OBJECTIVES AND SCOPE OF STUDY .1 Objectives
- Scope of Works
CHAPTER2
LITERATURE REVIEW
- BRAKING SYSTEM
- POWDER METALLURGY
- HARDNESS THEORY
- HARDNESS MEASUREMENT THEORY
- ROCKWELL HARDNESS TEST
- Position at which measurement is taken
- MPACT TEST
- EDX- ENERGY DISPERSIVE X-RAY ANALYSIS
By measuring the indentation depth, progressive degrees of pressure can be measured on the same piece. Using standard hardness conversion tables, the Rockwell hardness value is determined for the applied load, indenter diameter, and indentation depth. The Rockwell hardness tester for measuring metal hardness measures resistance to penetration like the Brinell test, but in the case of Rockwell, the depth of the impression is measured, not the diametrical area.
The difference in indentation depth between small and large loads provides the Rockwell hardness number. Impact strength is calculated by dividing the impact energy in J (or ft-lb) by the thickness of the sample. The incident electrons will also cause the generation of X-rays which is the basis of the EDX technique.
When the X-ray beam hits the detector, it will generate a photoelectron in the Si body. Thus, it is possible to obtain an X-ray spectrum that provides information on the elemental composition of the material under investigation.
CHAPTER3 METHODOLOGY
- SITE VISIT
- HARDNESS TEST PROCEDURE
- SAMPLE PREPARATION FOR THE IMPACT TEST
- IMPACT TEST PROCEDURE
- MICROSTRUCTURE TEST PROCEDURE
Since this project is a continuation project, there is only one sample left from the previous project; PUTRA LRT Brake Pads. Therefore, the specimens are marked with a horizontal and vertical line to build an invisible coordinate system to indicate the exact location on the brake key. But for PUTRA, hardness test will be done once after only used samples are taken.
Before then, the hardness of the sample will be read to ensure correct method. Therefore, its assembly to the back plate is more difficult to remove than the PUTRA brake pad. Detailed locations developed for both new and used STAR brake pads were as following figures.
This area will be where the samples will be taken and tested. Basically, figure 3.10 simply shows the area in which materials are taken to produce small parts. Therefore, the total number of impact test specimens to be generated for the STAR brake pad is 14.
For Ll and L3 is the number of smaller pieces, so the number of impact test specimens created will be 7. Figure 3.12 shows the hand tools that were used to process the larger brake pad pieces into smaller pieces and finally the desired standard specimens. Then the larger part was again cut into smaller pieces as shown in Figure 3.13, the cutting process was done with a hand saw.
The small samples were then labeled according to the area or location where the samples will then be taken using the stated hand tools, all small parts from the STAR and PUTRA brake pad will be finished to meet the standard specimen ASTM E-23 for the impact test. For microstructure test preparation, 6 locations each on PURTA and new and used brake pads were selected. Since the brake pad material is unknown, a suitable chemical reagent could not be determined and thus no etching was done to the samples.
CHAPTER4
RESULTS AND DISCUSSION
EXPERIMENTAL RESULT
- Hardness Test Result
Hardness Value for new and used STAR LRT Brake Pad in Coordinate location
Hardness Value for the Used PUTRA brake pad at coordinate location
Point
Impact Test Result
Microstructure Test Result
DISCUSSION OF THE RESULT
- Discussion of Hardness Test Result
- Discussion oflmpact Test Result
In general, the used brake pad has a higher HR V value than the new one. It is believed to be the result of the greater HRV value of used STAR brake pads. This is evidenced by all points in the used STAR pad having a relatively greater HRV value than the new STAR pad.
Harju,2002] The variation of the hardness profile of the used STAR brake pad, as can be seen from the graph, is relatively larger from the new STAR brake pad. This variation in the HRV value of used STAR brake pads also occurs with the effect of uneven pad loading. From Table 4.3, the value obtained for new STAR brake pads was relatively more loved than used STAR brake pads.
From the calculation, the standard deviation therefore indicates that the variation of the impact test values for the used STAR brake pad was 2.853. However, the variation of the impact test value for both used and new STAR brake pad was smaller than the variation in their hardness value. The variation can be considered relatively very small, as evidenced by the calculation of the standard deviation for the new STAR brake pad was only 0.053.
Therefore, the result showed that the used STAR brake pad is not only harder but less brittle than the new STAR brake pad. The used brake pad can absorb more energy compared to the new STAR brake pad. Finally, the value of impact energy of PUTRA brake pad is almost similar to the STAR brake pad.
The result obtained from the impact test, the PUTRA brake pad has given a relatively low impact energy value and thus much more fragile than the new STAR brake pad. But for the used STAR brake pad, the dominant shiny particles can be seen more than the new STAR brake pad. As a result, the used STAR brake pad offers higher value of mechanical properties in place than the new STAR brake pad as well as the PUTRA brake pad.
CHAPTERS
CONCLUSION AND RECOMMENDATION
Simulation of brake sequences and associated brake wear, R Harju, Brake and Suspension Systems, Scania CV AB, Sodertalje, Sweden.
APPENDICES
Complete List of Rockwell Hardness Scale
Steel, hard cast irons, pearlitic malleable iron~- titanium, deep case hardened steel and the 150 kg 10 kg materials harder than HRB 100.
Site Visit to STAR LRT at Jalan Am pang, Am pang
It is the brake hydraulic system that forces the brake pad to work against the disc. On the left is a used brake pad and on the right is an unused brake pad.
Site Visit to PUTRA LRT, Jalan Lapangan Terbang Snbang, PJ
