In modern world, the use of sophisticated equipments with high production capacity such as draglines, it is important that the equipment must be functional in a consistent way in order to maximise its utilization and the profits. In this way reliability analysis is important to assess reliability and frequency of failure so that this information can be used to plan maintenance activities to increase the available time of equipments. It is imperative that reliability of such critical equipment is to be high. Though various methods are available to remove the overburden, draglines are found commonly used for this purpose. In this research project, mechanical failures of components of a dragline have been considered. The TBF data was tested for Independent and Identical characteristics (IID) to examine whether any trend and serial correlation exist between them. Reliability estimates for different critical components have been made according to best-fit distribution. Then the components of the dragline have been compared in terms of reliability. The hitch shackle attached to the bucket of a dragline was then selected to conduct the further failure analysis. Investigative tools such as non-destructive testing, mechanical property measurements and chemical analysis were used to determine the root causes of failure. This study was made to assist engineers associated with mining industries to identify the critical subsystems in the draglines for better maintenance planning, leading to enhanced equipment availability, reduced maintenance costs.

1. RELIABILITY AND FAILURE ANALYSIS OF
CRITICAL COMPONENTS OF A DRAGLINE
1
By
Pranami Rajkhowa (15MT000522)
Maintenance Engineering and Tribology
Under the guidance of
Prof. Somnath Chattopadhyaya (Associate Professor)
Prof. Dr. Sc. Drazan Kozak
(Head of Department of Mechanical Design, J.J. Strossmayer University of Osijek, Croatia)
Dr. Dipankar Ray (System Programmer)
Department of Mechanical Engineering
Indian Institute of Technology (ISM), Dhanbad, Jharkhand

2. Outline for presentation
Introduction
Literature review
Research Objectives
Methodology
Experimental work
Conclusion and future work
References
Publications
2

3. INTRODUCTION
•Reliability
•Draglines
•Why draglines are chosen over other mining equipments: fast controlling, less requirement of manpower, less
production cost, high production rate and flexibility.
3
Fig 1. Functions of a dragline

4. LITERATURE REVIEW
1. Bandopadhyay & Ramani :(1985) developed a simulation model , concluded that availability and cycle
time affects the productivity.
2. Guan et al. :(1999) stress monitoring along the boom; identified the importance of the operating
performance on machine availability.
3. Silviu: (2000) component’s failure leads to major breakdown of the system.
4. Demirel et al. :(2014) estimated the lifetime of the components which helped to estimate the possible
failures.
5. Rai, Trivedi & Nath: (2000) analyzed the cycle time and the idle time frequency distribution.
6. Townson, Murthy & Gurgenci: (2003) effect of load and operator efficiency on the availability,
maintenance and output.
4

5. Research Objectives
• To evaluate the reliability of the
critical components and to estimate
the overall reliability of the dragline.
• To estimate the MTBF for 90%
reliable life.
• To provide a comparative analysis of
the reliability of the components.
• To conduct the failure analysis of the
critical component.
5

6. Criticality Analysis of the Subsystems
6
0
50
100
150
200
250
300
350
400
450
Bucket and
Accessory
Drag Chain Ropes Gear
Assembly
Motor and
Generator
Swing
Mechanism
Walk
Mechanism
Structure Lubrication
RPN
Sub Systems
Series1
Expon. (Series1)
Fig 2. Criticality analysis of the subsystem

7. I
Data Collection
II II
Determination of Presence
of Trend and Correlation
(IID)
III
Determination of the best
fit statistical distribution
IV
Reliability Analysis
7
METHODOLOGY
Fig 3. Trend test of TBFs data for bucket
Fig 4. Correlation test of TBFs data for bucket

8. 8
Subsystems MTBF (Days) K-S Test (D value) Best fitment of curve
Bucket and accessory 5.175 99.984 Lognormal
Drag chain 9.659 89.760 Lognormal
Gear assembly 36.960 9.038 Lognormal
Motor generator 17.481 35.446 Lognormal
Ropes 20.291 21.051 Gamma
Others 20.291 92.976 Gamma
Table 1. Parameters of distributions for the Dragline
Components Bucket and
accessory
Drag chain Gear assembly Motor
generator
Ropes Other
componnets
MTBF (Days) 25.046 43.383 13.906 25.445 39.315 22.235
Table 2. MTBF for 90% reliable life of the components of the dragline

9. 9
Fig 6. Reliability Vs Time graph for the draglineFig 5. Reliability Vs Time graph for all the critical components

10. Accessories attached
to a bucket
Main body
Hoist chain
Dump block
Tooth and adapter
Hitch shackle
10
Fig 7. Bucket and its accessory

11. Hitch shackle of a dragline
11
Fig 8. Shackle of a dragline
Fig 9. Hitch shackle

12. Failure analysis
of hitch shackle
Faculty of Mechanical Design, J.J. Strossmayer
University of Osijek, Slavonski Brod, Croatia.
Faculty of Mechanical and Naval Architecture,
University of Zagreb, Zagreb, Croatia.
Collection of background information
Preliminary visual inspection
Modeling
Surface and subsurface inspection using
NDTs
Metallographic Examination
Destructive Tests
Chemical Composition
12

13. Preliminary visual inspection of the component
13
Fig 10. Specimen of shackle
Specimen for further analysis was cut using a oxy-
acetylene flame.

14. Modeling
14
Fig11. 3D image of Shackle Fig 12. Front view of shackle

15. 15
Fig 13. Side view of shackle

16. Surface and subsurface
inspection using NDTs
1. Computed Radiography
(CR)
16
Fig 14. Experimental setup for carrying out computed radiography

17. Results of Computed Radiography (CR)
17
Fig 15. Cracks on surface I

18. 18
Fig 16. Cracks on surface II

19. 2. Magnetic Particle
Inspection (MPI)
19
Fig 17. Experimental setup for Magnetic particle inspection test

20. Results of MPI
20
Fig 18. Magnetic particle inspection for the shackle

21. Metallographic Examination
21
Fig 19. Cutting samples (MC-80 Specimen cutter) Fig 20. Grinding and polishing samples (GP-2B Grinder Polisher)

22. 22
Fig 21. Test sample for metallographic test Fig 22. Marked locations for recording microstructure

23. Microstructure
Location 1
23
Fig 23. Magnification: 200X (without etching) Fig 24. Magnification: 100X (after etching)

24. Location 2
24
Fig 26. Magnification: 50x (after etching)Fig 25. Magnification: 50x (without etching)

25. Location 3
25
Fig 27. Magnification: 50x (without etching) Fig 28. Magnification: 50x (after etching)

26. Location 4
26
Fig 29. Magnification: 50x (without etching) Fig 30. Magnification: 50x (after etching)

27. Destructive Test
Here,
F: Test load applied in kgf
d: average value of the two
diagonals
27
• Vickers Hardness Test
Hardness Value is given by,
Fig 31. Vickers hardness apparatus

28. Type / Load: HV 10
28
Location 1 2 3 4 Average
hardness
Rm
Test
Sample 1
146 146 138 141 143 470
Test
Sample 2
142 146 139 142 144 470
Rm : Tensile strength (MPa) calculated from the average hardness for metallic materials (DIN 50150).
Table 3. Result of hardness measurement

29. Chemical Composition
29
Weight % C Si Mn P S Cu Cr
Test
Sample
0.21 0.274 0.264 0.043 0.041 0.109 0.087
Table 4. Chemical composition of the specimen

30. Conclusion and Future scope
30
•The Lognormal and Gamma distribution provides the best fit distribution for most of the subsystems.
•Among all the subsystems, bucket and accessory is the most vulnerable component to failure as compared to others. MTBF is
minimum for bucket and accessory (5.175 days) and maximum for gear assembly (36.960days).
•For 90% reliable life, Drag chain has the maximum service life of 43.383 hours.
•The CR, MPI images and metallographic analysis reveals the presence of cracks on both the surfaces.
•The lack of adequate data related to the loading conditions creates complexity to understand the effect of the external forces
on the deformation or failure of hitch shackle. Thus exploitation conditions can also be a major cause behind the shackle
failure.
•Also shackle can suffer damage due to external factors, not necessarily related to its operation. These may include damages
due to impact from other objects or vehicles and thermal damage caused by careless welding or metal cutting in the vicinity of
the shackle.

31. REFERENCES
31
[1] Ascher, H., & Feingold, H. Repairable systems reliability: modeling, inference, misconceptions and their causes.
New York: M. Dekker. (1984), p. 232
[2] Bandopadhyay, S., &Ramani, R. V. Simulation of a dragline operation in an Eastern Kentucky mine. CIM
BULLETIN,78(882) (1985),pp 52-58.
[3] Barabady, J., & Kumar, U.. Reliability analysis of mining equipment: A case study of a crushing plant at Jajarm
Bauxite Mine in Iran. Reliability engineering & system safety, 93(4), (2008), pp.647-653.
[4] Barabady, J., & Kumar, U. Reliability and maintainability analysis of crushing plants in Jajarm Bauxite Mine of
Iran. In Proceedings of the Annual Reliability and Maintainability Symposium (2005, January) .pp. 109-115.
[5] Birolini, A. Reliability engineering (Vol. 5). Heidelberg: Springer. (2007).
[6] Demirel, N., Gölbaşi, O., Düzgün, Ş., &Kestel, S. System Reliability Investigation of Draglines Using Fault Tree
Analysis. In Mine Planning and Equipment Selection Springer International Publishing. (2014), pp. 1151-1158.
[7] Esmaeili, M., Bazzazi, A. A., & Borna, S. Reliability analysis of a fleet of loaders in Sangan iron mine. Archives
of mining sciences, 56(4), (2011). 629-640.
[8] Guan, Z., Gurgenci, H., Austin, K., & Fry, R. Optimisation of design load levels for dragline buckets. Australian
Coal Association Research Program, CSIRO Division of Exploration and Mining, Final Report, (C7003), (1999) 87.
[9] Kumar, U., Klefsjö, B., & Granholm, S. Reliability investigation for a fleet of load haul dump machines in a
Swedish mine. Reliability Engineering & System Safety, 26(4), (1989)341-361.
[10] Mohammadi, M., Rai, P., & Gupta, S.. Improving productivity of dragline through enhancement of reliability,
inherent availability and maintainability. ActaMontanisticaSlovaca, 21(1), (2016)1-8.

32. PUBLICATIONS
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• Sheeba Borkakoti, Anil Kumar Agrawal, Pranami Rajkhowa, “Reliability analysis for critical components of draglines”,
International Journal of Mining Science and Technology Status: Communicated and under review.
• Ankit Kotia, Pranami Rajkhowa, Gogineni Satyanarayana Rao, Subrata Kumar Ghosh, “Thermophysical and
tribological properties of nanolubricants: A review”, Heat and Mass Transfer, Status: Communicated and under review.
• Anil Kumar Agrawal, Pranami Rajkhowa, Sheeba Borkakoti, Somnath Chattopadhyaya, “Failure analysis of
components of a diesel engine” pp. 84-87, National Conference on Recent advances in Industrial Tribology and
Maintenance, February, 2017.
• Sheeba Borkakoti, Anil Kumar Agrawal, Pranami Rajkhowa, Somnath Chattopadhyaya, Alokesh Pramanik, “Risk
analysis using failure mode effects and criticality analysis (FMECA) for mining equipments” pp. 238-242, International
Conference on Evolution in Manufacturing, November, 2016.
• Ankit Kotia, Sheeba Borkakoti, Pranami Rajkhowa, Subrata Kumar Ghosh, “Experimental Investigation of Aluminium
Oxide Nanoparticle as additives of HEMM Gear Oil” National Conference on Tribology: Energy, Environment and
Efficiency organized by Tribological Society of India, Bhopal held at Bhopal, Madhya Pradesh, India, January, 2016.

33. THANK YOU
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