A Stochastic Study on Fatigue Crack Propagation and Retardation Behavior of Pressure Vessel Steel

J. Ocean Eng. Technol. 1995;9(1):132-141.

압력용기용강의 피로균열전파 및 지연거동에 관한 확률통계적 연구

김선진,남기우,김부안

부산수산대학교 기계공학과,부산수산대학교 기계공학과,부산수산대학교 재료공학과

Keywords: Fatigue Crack Propagation, Retardation Behavior, Statistical Characteristics, Stocastic Process, Material Resistance

핵심용어: 피로균열전파, 지연거동, 통계적특성, 확률과정, 재료저항

Abstract

The purpose of the present study is to investigate the statistical characteristics of m and C in the fatigue crack propagation law, da/dN=C(.DELTA.K)/sup m/ and to studies on the randomness of fatigue crack propagation and retardation behavior. Fatigue tests were perfomed on 32 CT specimens of SPV50 steel under the same one condition. First, the value of m and C were determined for each specimen, and all the data were analyzed statistically. second, the material's resistance to fatigue crack propagation is modeled as a stchastic process, which varies randomly along the crack path. The statistical analysis of the material resistance is performed with the data obtained by constant load controlled tests. Finally, retardation behavior was examined experimentally by using a CT specimen, and a retardation parameters were analyzed statistically.