Investigation of Failure Mechanism of a DCI Engine Connecting Rod

Abstract

In reciprocating engines, connecting rod cap and connecting bolts are critical as they are exposed to varying loads under different operating conditions. This paper focused on the failure of the connecting rod of a 1.5 dci K9K diesel engine. As a result of the engine operating for approximately 378400 km, the connecting rod was broken, and the reasons for the failure of the connecting rod cap and connecting bolt were investigated. The connecting rod of the K9K engine was designed in accordance with the dimensions in SolidWorks software and then exported to ANSYS software for stress and fatigue analysis. Also, the macrostructure of the broken connecting rod cap and bolt was investigated. We knew that the mechanic who fixed the engine about two years ago tightened the connecting rod bolts without using a torque meter. Therefore, stress and fatigue analyzes were performed to determine the effect of different tightening torques (ranging from 22.5 to 52.5 Nm) at 2000 rpm. According to the numerical analysis results, with increasing tightening torque, the maximum equivalent stress and alternating stress values increased significantly, while the fatigue safety factor and the cyclic life of the connecting rod decreased. First, a fatigue fracture occurred in the right hand bolt. Immediately after, the lower cup deformed and crashed to the cylinder liner. Therefore, a brittle fracture occurred on the left shoulder of the connecting rod shank. The chevron markings were clearly visible in the macrostructure as evidence of brittle fracture.

Keywords

• Failure analysis
• Connecting rod
• Stress
• Fatigue
• Finite element analysis

References

1. S. Fukuda and H. Eto, ‘Development of fracture splitting connecting rod’, JSAE Rev., vol. 23, no. 1, pp. 101–104, 2002, doi: 10.1016/S0389-4304(01)00154-0.
2. Z. Pan and Y. Zhang, ‘Numerical investigation into high cycle fatigue of aero kerosene piston engine connecting rod’, Eng. Fail. Anal., vol. 120, pp. 1–13, 2021, doi: 10.1016/j.engfailanal.2020.105028.
3. A. Gautam, ‘Static Stress Analysis of Connecting Rod Using Finite Element Approach’, IOSR J. Mech. Civ. Eng., vol. 10, no. 1, pp. 47–51, 2013, doi: 10.9790/1684-1014751.
4. P. Singh, D. Pramanik, and R. V. Singh, ‘Fatigue and Structural Analysis o f Connecting Rod ’ s Material Due to ( C . I ) Using FEA’, Int. J. Automot. Eng. Technol., vol. 4, no. 4, pp. 245–253, 2015.
5. A. Muhammad, M. A. H. Ali, and I. H. Shanono, ‘Design optimization of a diesel connecting rod’, Mater. Today Proc., vol. 22, pp. 1600–1609, 2019, doi: 10.1016/j.matpr.2020.02.122.
6. B. yan He, G. da Shi, J. bing Sun, S. zhuan Chen, and R. Nie, ‘Crack analysis on the toothed mating surfaces of a diesel engine connecting rod’, Eng. Fail. Anal., vol. 34, pp. 443–450, 2013, doi: 10.1016/j.engfailanal.2013.09.004.
7. X. L. Xu and Z. W. Yu, ‘Failure analysis of a diesel engine connecting rod’, J. Fail. Anal. Prev., vol. 7, no. 5, pp. 316–320, 2007, doi: 10.1007/s11668-007-9058-9.
8. G. T. Reddy and C. Srinivas, ‘Fatigue analysis and life predictions of Forged steel and Powder Metal connecting rods’, IOSR J. Mech. Civ. Eng., vol. 16, no. 053, pp. 15–19, 2016, doi: 10.9790/1684-16053031519.

9. M. N. Ilman and R. A. Barizy, ‘Failure analysis and fatigue performance evaluation of a failed connecting rod of reciprocating air compressor’, Eng. Fail. Anal., vol. 56, pp. 142–149, 2015, doi: 10.1016/j.engfailanal.2015.03.010.
10. M. N. Mohammed, M. Z. Omar, S. Zainuddin, A. Salah, M. A. Abdelgnei, and M. S. Salleh, ‘Failure analysis of a fractured connecting rod’, J. Asian Sci. Res., vol. 2, no. 11, pp. 737–741, 2009.
11. S. Khare, O. P. Singh, K. Bapanna Dora, and C. Sasun, ‘Spalling investigation of connecting rod’, Eng. Fail. Anal., vol. 19, no. 1, pp. 77–86, 2012, doi: 10.1016/j.engfailanal.2011.09.007.
12. S. Rakic, U. Bugaric, I. Radisavljevic, and Z. Bulatovic, ‘Failure analysis of a special vehicle engine connecting rod’, Eng. Fail. Anal., vol. 79, no. April, pp. 98–109, 2017, doi: 10.1016/j.engfailanal.2017.04.014.
13. C. Juarez, F. Rumiche, A. Rozas, J. Cuisano, and P. Lean, ‘Failure analysis of a diesel generator connecting rod’, Case Stud. Eng. Fail. Anal., vol. 7, pp. 24–31, 2016, doi: 10.1016/j.csefa.2016.06.001.
14. A. Saravanan, P. Suresh, G. Sudharsan, and V. Suresh, ‘Static analysis and weight reduction of aluminum casting alloy connecting rod using finite element method’, Int. J. Mech. Prod. Eng. Res. Dev., vol. 8, no. 3, pp. 507–518, 2018, doi: 10.24247/ijmperdjun201855.
15. P. Sarate, G. R. Kesheorey, and M. Shah, ‘A Comparative Study on Forecasting and Analysis of 4140 Material Composition of Connecting Rod for Various Applications’, no. November, 2017.
16. M. A. Rezvani, D. Javanmardi, and P. Mostaghim, ‘Diagnosis of EMD645 diesel engine connection rod failure through modal testing and finite element modeling’, Eng. Fail. Anal., vol. 92, no. January, pp. 50–60, 2018, doi: 10.1016/j.engfailanal.2018.05.005.
17. R. Rabb, ‘Fatigue failure of a connecting rod’, Eur. Struct. Integr. Soc., vol. 22, no. C, pp. 97–112, 1997, doi: 10.1016/S1566-1369(97)80011-8.
18. K. Bari, A. Rolfe, A. Christofi, C. Mazzuca, and K. V. Sudhakar, ‘Forensic investigation of a failed connecting rod from a motorcycle engine’, Case Stud. Eng. Fail. Anal., vol. 9, no. May, pp. 9–16, 2017, doi: 10.1016/j.csefa.2017.05.002.
19. S. Y. Lee, S. B. Lee, H. S. Kim, T. G. Kim, M. G. Kam, and J. W. Yoon, ‘Failure Analysis of Connecting Rod at Big End’, Key Eng. Mater., vol. 306–308, pp. 345–350, 2006, doi: 10.4028/www.scientific.net/kem.306-308.345.
20. A. Andoko et al., ‘Failure analysis on the connecting rod by finite element method’, AIP Conf. Proc., vol. 2262, no. September, 2020, doi: 10.1063/5.0015728.
21. A. Mirehei, M. Hedayati Zadeh, A. Jafari, and M. Omid, ‘Fatigue analysis of connecting rod of universal tractor through finite element method (ANSYS)’, J. Agric. Technol., vol. 4, no. 2, pp. 21–27, 2008.
22. T. G. Thomas, S. Srikari, and M. L. . Suman, ‘Design of Connecting Rod For Heavy Duty Applications Produced By Different Processes For Enhanced Fatigue Life’, SasTech J., vol. 10, no. 1, pp. 1–7, 2011.
23. M. Ranjbarkohan, M. R. Asadi, M. Mohammadi, and A. Heidar, ‘Fatigue analysis of connecting rod of samand engine by Finite Element Method’, Aust. J. Basic Appl. Sci., vol. 5, no. 11, pp. 841–845, 2011.
24. L. Witek and P. Zelek, ‘Stress and failure analysis of the connecting rod of diesel engine’, Eng. Fail. Anal., vol. 97, pp. 374–382, 2019, doi: 10.1016/j.engfailanal.2019.01.004.
25. S. Griza, F. Bertoni, G. Zanon, A. Reguly, and T. R. Strohaecker, ‘Fatigue in engine connecting rod bolt due to forming laps’, Eng. Fail. Anal., vol. 16, no. 5, pp. 1542–1548, 2009, doi: 10.1016/j.engfailanal.2008.10.002.
26. X. Zhu, J. Xu, Y. Liu, B. Cen, X. Lu, and Z. Zeng, ‘Failure analysis of a failed connecting rod cap and connecting bolts of a reciprocating compressor’, Eng. Fail. Anal., vol. 74, pp. 218–227, 2017, doi: 10.1016/j.engfailanal.2017.01.016.
27. A. Acri, S. Beretta, F. Bolzoni, C. Colombo, and L. M. Vergani, ‘Influence of manufacturing process on fatigue resistance of high strength steel bolts for connecting rods’, Eng. Fail. Anal., vol. 109, no. May 2019, p. 104330, 2020, doi: 10.1016/j.engfailanal.2019.104330.
28. N. C. Nutu, C. Pana, N. Negurescu, A. Cernat, D. Fuiorescu, and L. Nemoianu, ‘An experimental approach on fuelling a passenger car diesel engine with LPG’, IOP Conf. Ser. Mater. Sci. Eng., vol. 444, no. 7, 2018, doi: 10.1088/1757-899X/444/7/072001.
29. M. Tuti, Z. Şahin, and O. Durgun, ‘Thermodynamic diesel engine cycle modeling and prediction of engine performance parameters’, Gmo-Shipmar, vol. 207, no. March, pp. 14–26, 2017, [Online]. Available: https://www.journalagent.com/gmo/pdfs/GMO_23_207_14_26.pdf.
30. Renault, ‘Technical Note6006A KXX, and K9K engine - Engine workshop repair manual’, 2004.
31. M. T. Alam, A. Thakur, V. Kumar PS, and S. Ghadei, ‘Fatigue Failure Analysis of Diesel Engine Connecting Rod’, in SAE Technical Papers, Jul. 2018, vol. 2018-July, pp. 1–8, doi: 10.4271/2018-28-0067.
32. J. W. Sowards, C. N. McCowan, and E. S. Drexler, ‘Interpretation and significance of reverse chevron-shaped markings on fracture surfaces of API X100 pipeline steels’, Mater. Sci. Eng. A, vol. 551, pp. 140–148, 2012, doi: https://doi.org/10.1016/j.msea.2012.04.108.