Application of Kaplan-Meier analysis in reliability evaluation of products cast from aluminium alloys
Journal Title: Archiwum Odlewnictwa - Year 2010, Vol 10, Issue 2
Abstract
The article evaluates the reliability of AlSi17CuNiMg alloys using Kaplan-Meier-based technique, very popular as a survival estimation tool in medical science. The main object of survival analysis is a group (or groups) of units for which the time of occurrence of an event (failure) taking place after some time of waiting is estimated. For example, in medicine, the failure can be patient’s death. In this study, the failure was the specimen fracture during a periodical fatigue test, while the survival time was either the test duration to specimen failure (complete observations), or the test end time (censored observations). The parameters of theoretical survival function were estimated with procedures based on the method of least squares, while typical survival time distribution followed either an exponential or two-parameter Weibull distribution. The goodness of fit of a model survival function was estimated with an incremental chi-square test, based on the values of the log likelihood ratio. The effect of alloy processing history on the run of a survival function was examined. The factors shaping the alloy processing history included: mould type (sand or metal mould), alloy modification process, and heat treatment type (solution heat treatment and ageing).
Authors and Affiliations
J. Szymszal, A. Gierek
Keywords
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