Effect of Material Properties on the Structural Integrity of Honda Supra Crankshaft - An FEA Approach

Abstract

This study presents a detailed finite element analysis of the crankshaft for a Honda Supra motorcycle, focusing on the static and fatigue behavior under realistic loading conditions. The crankshaft model was developed in Autodesk Inventor, including the inner bearing rings for a more accurate simulation, and imported into ANSYS for analysis. Three materials: 42CrMo4 Alloy Steel, AISI 1045 Steel, and AISI 4340 Steel, were compared based on their stress distribution, deformation, and safety factors. The results indicate that AISI 1045 Steel offers the best fatigue resistance, AISI 4340 Steel provides superior stiffness, and 42CrMo4 Alloy Steel represents a balanced, cost-effective choice. These findings support informed material selection depending on the desired balance between durability, rigidity, and efficiency, contributing to the optimization of crankshaft design in motorcycle engines.

Introduction

The crankshaft is a critical component of internal combustion engines, converting piston linear motion into rotational motion. It operates under complex multi-axial stresses, including torsion, bending, and cyclic loads, making fatigue failure a key concern. Finite Element Analysis (FEA) and numerical simulations are widely used to study stress distribution, optimize geometry, and predict fatigue life. Research shows that material choice, surface treatments (e.g., fillet rolling, nitriding), and geometric optimization can significantly improve crankshaft durability and reduce manufacturing costs.

In this study, the Honda Supra crankshaft was modeled in Autodesk Inventor with bearing inner rings included for realistic FEA in Ansys. Three materials—42CrMo4 Alloy Steel, AISI 1045 Steel, and AISI 4340 Steel—were analyzed under static and fatigue loading conditions, considering engine torque and cylinder pressure. Results showed:

• 42CrMo4 Alloy Steel: Max stress 269.83 MPa, max deformation 3.611 mm, static FOS 3.521, fatigue FOS 1.835.

• AISI 1045 Steel: Max stress 264.48 MPa, max deformation 3.648 mm, static FOS 6.9, fatigue FOS 3.517, offering excellent fatigue resistance.

• AISI 4340 Steel: Max stress 267.06 MPa, max deformation 1.999 mm, static FOS 4.411, fatigue FOS 2.089, showing high stiffness and good durability.

Conclusion

The comparison of the three materials showed distinct advantages for each. AISI 1045 Steel offers the highest safety factors for both static and fatigue loads, making it the most durable choice. AISI 4340 Steel provides the best rigidity with the lowest deformation, balancing strength and fatigue resistance. Meanwhile, 42CrMo4 Alloy Steel is a cost-effective option but has lower fatigue safety margins. The final material selection should consider the project priorities: durability, rigidity, or cost efficiency. Among the three materials, AISI 1045 Steel stands out for durability, showing the highest safety factors under both static and fatigue conditions. AISI 4340 Steel excels in rigidity, with the lowest maximum deformation, making it ideal where stiffness is crucial. For efficiency (balancing cost and performance), 42CrMo4 Alloy Steel is a viable option, though with lower fatigue safety. Therefore, AISI 1045 Steel is preferred for long-lasting applications, AISI 4340 Steel for applications requiring higher stiffness, and 42CrMo4 Alloy Steel for cost-sensitive projects.

References

[1] J. A. Becerra, F. J. Jimenez, M. Torres, D. T. Sanchez, E. Carvajal, “Failure analysis of reciprocating compressor crankshafts”, Eng. Fail. Anal., 18, 735, 2011. [2] W. Y. Chien, J. Pan, D. Close, S. Ho, “Fatigue analysis of crankshaft sections under bending with consideration of residual stresses”, Int. J. Fatigue, 27, 1, 2005. [3] S.A. Kyrre, B. Skallerud, W.T. Tveiten, and B. Holme, “Fatigue Life Prediction of Machined Components Using Finite Element Analysis of Surface Topography”, Int. J. of Fatigue, 27, pp. 1590- 1596, 2005. [4] C.M. Balamurugan, R. Krishnaraj, M. Sakthivel, “Computer Aided Modeling and Optimization of Crankshaft”, International Journal of Scientific & Engineering Research, ISSN 2229-5518, Issue 8, vol.2, pp.1-6, 2011. [5] H. Farzin Montazersadgh, “Optimization of a Forged Steel Crankshaft Subject to Dynamic Loading”, SAE International, Paper No 2008-01-0432, 2008. [6] T.C. Chatterley, and P. Murrell, “ADI Crankshafts- An Appraisal of Their Production Potentials”, SAE Technical Paper No. 980686, Society of Automotive Engineers, 1998. [7] H. Park, Y. S. Ko, and S. C. Jung, “Fatigue Life Analysis of Crankshaft at Various Surface Treatments”, SAE Technical Paper No. 2001-01-3374, Society of Automotive Engineers, 2001. [8] J. Brahmbhatt, C. Abhishek, “Design and Analysis of Crankshaft for Single Cylinder 4-Stroke Diesel Engine”, International Journal of Advanced Eng. Research And Studied, ISSN: 2249-8974, vol.1, Issue-IV, pp.88-90, 2012. [9] G. Rinkle, B. Sunil, “Finite Element Analysis and Optimization of Crankshaft Design”, International Journal of Eng. and Management Research, ISSN: 2250-0758, vol-2, Issue-6, pp: 26-31, (2012). [10] J. Bagde Bhumesh, P. Raut Laukik, “Finite Element Analysis of Single Cylinder Engine crankshaft”, International Journal of Advances in Engineering &Technology, ISSN: 2231-1963, vol. 6, Issue 2, pp. 981-986, 2013. [11] V. M. Reddy, T. V. Devi, “Design, analysis and optimization of a 6 cylinder engine crank shaft”, Int. J. Mod. Eng. Res. Technol., 4, 30, (2013). [12] Z. P. Mourelatos, “A crankshaft system model for structural dynamic analysis of internal combustion engines”, Comput. Struct., 79, 2009, 2001. [13] J. Brahmbhatt, A. Choubey, “Design and analysis of crankshaft for single cylinder 4-stroke diesel engine”, Int. J. Adv. Res. Technol., 1, 88, 2012.

Copyright

Copyright © 2025 Valentin Mereuta. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.