Journal of Failure Analysis and Prevention

, Volume 9, Issue 4, pp 323–328 | Cite as

Fracture Characteristics of Fatigue Failure of a Vehicle’s Ductile Iron Steering Knuckle

  • G. K. Triantafyllidis
  • A. Antonopoulos
  • A. Spiliotis
  • S. Fedonos
  • D. Repanis
Case History---Peer-Reviewed

Abstract

The steering knuckle, being a part of the vehicle’s steering and suspension system, undergoes time-varying loading during its service life. Since it is connected to the steering parts and strut assembly from one side and the wheel hub assembly from the other, it has complex restraint and constraint conditions and tolerates a combination of loads. In addition, parameters such as internal defects, stress concentrations and gradients, surface finish, and residual stresses can have considerable influence while designing for fatigue. A vehicle with a 2.500 cm3 (2.5 L) volume engine was being driven during a rainy day in a congested road at a speed of about 10 km/h, when suddenly the vehicle lost its orientation and crushed over a parked vehicle on the right side of the road without any human injury. The driver insisted that he heard an intense noise of a metal undergoing rupture from the front right side of the vehicle’s suspension system and immediately lost control of the vehicle. The producing company of the vehicle on the other hand, after on-site visual inspection, came to the conclusion that due to the driver’s error the vehicle turned to the right and as a consequence of the crash the steering knuckle was broken into two parts. Failure analysis conducted as presented in this article reveals the mechanism of fracture mainly due to bending fatigue.

Keywords

Steering knuckle Ductile iron Fracture (ductile-brittle) Fractography Fatigue 

References

  1. 1.
    The Sorelmetal Book of Ductile Iron, Rio–Tinto Iron and Titanium Inc., Montreal, QC, Canada, First Printing 2004Google Scholar
  2. 2.
    Svensk Standard SS 11 21 27, MNC MetallnormcentralenGoogle Scholar
  3. 3.
    Victor, K.: Modes of Fracture, Fractography. ASM Handbook, vol. 12, pp. 21, 22, 29. ASM International, Materials Park, OH (1995)Google Scholar
  4. 4.
    Lampman, S.: Fatigue and Fracture Properties of Cast Irons, Fatigue and Fracture. ASM Handbook, vol. 19, pp. 665–666. ASM International, Materials Park, OH (1997)Google Scholar
  5. 5.
    Zoroufi, M., Fatemi A.: Fatigue Life Comparisons of Competing Manufacturing Processes: A Study of Steering Knuckle, SAE Transactions, SAE Technical Paper No. 2004-01-0628, 2004Google Scholar

Copyright information

© ASM International 2009

Authors and Affiliations

  • G. K. Triantafyllidis
    • 1
  • A. Antonopoulos
    • 1
  • A. Spiliotis
    • 1
  • S. Fedonos
    • 1
  • D. Repanis
    • 2
  1. 1.Faculty of Engineering, Chemical Engineering Department, Laboratory of Materials TechnologyAristotle University of ThessalonikiThessalonikiGreece
  2. 2.Hitiria Makedonias SA, SindosThessalonikiGreece

Personalised recommendations