The engine valve spring is a very important component in automotive engine systems. The non-metallic inclusions in an engine valve spring will significantly reduce its reliability. In this study, an attempt was made to establish a correlation between fatigue failures and non-metallic inclusions by applying statistical methods. Fatigue tests with BZ and OTEVA-90 materials are performed with two different types of experiments, which are rotating bending fatigue test (Nakamura test) and spring fatigue test. By using RELIASOFT, the data of these two tests are analyzed with the Weibull distribution in order to statistically estimate BZ and OTEVA-90's fatigue lives at 90% low confidence under different stresses. On the other hand, fatigue strength of these materials can be estimated by Murakami and Endo's model with maximum inclusion size predicted from the Gumbel distribution.
Study of the Fatigue Failure of Engine Valve Springs Due to Non-Metallic Inclusions
Sae Int. J. Mater. Manf
Sae International Journal of Materials and Manufacturing
SAE 2012 World Congress & Exhibition ; 2012
Sae International Journal of Materials and Manufacturing ; 5 , 2 ; 388-394
2012-04-16
7 pages
Conference paper
English
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