Journal of Failure Analysis and Prevention

, Volume 13, Issue 3, pp 340–345 | Cite as

Fatigue Fracture of a Truck Diesel Engine Rocker-Bracket

  • Xiao-lei Xu
  • Yu-zhou Gao
  • Zhi-wei Yu
Technical Article---Peer-Reviewed


A diesel engine rocker-bracket fractured after trial running for 460 h. Fracture originated from the fillet root of cylinder of rocker-bracket. Fractographic analysis indicates that fatigue is the dominant failure mechanism of the rocker-bracket. Serious wear damage took place in the located region of the contact surfaces between the cylinder of the rocker-bracket and the rocker-arm. Occurrence of a great abnormal alternative bending load on the cylinder of rocker-bracket from the assembled rocker-arm is mainly responsible for the fracture failure of the rocker-bracket. The over-small root fillet radius of cylinder of rocker-bracket (below the specified limit) increases the stress concentration at the fillet to facilitate initiation and propagation of crack, and eventually premature fracture.


Rocker-bracket Abnormal bending load Fatigue fracture Root fillet Stress concentration 


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Copyright information

© ASM International 2013

Authors and Affiliations

  1. 1.Electromechanics and Material Engineering CollegeDalian Maritime UniversityDalianPeople’s Republic of China

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