ICONE19-43186 Fatigue Failure by In-line Flow-induced Vibration : Fatigue Crack Detection and Fatigue Life Evaluation

Abstract

The phenomenon of fatigue failure due to In-line flow-induced vibration has been investigated. In the experimental program an induced-vibration experimental set-up involving water flow was developed. This apparatus was used to produce fatigue failure resulting from In-line flow-induced vibration. The fatigue test cylinders were made of medium carbon steel. A small hole was drilled onto the test cylinder surface to localize the fatigue cracking process. A strain histogram recorder was used to acquire the service strain histogram and also to detect any variation in natural frequency. The cumulative fatigue damage, D, as defined by the Modified Miner Rule, was determined by using the strain histogram of the early portion of the test record. The value of D was close to unity in the case of In-line vibration. In contrast, the value of D obtained in a previous investigation for the case of the Cross-flow vibration ranged approximately from 0.2 to 0.8.