Fatigue Crack Growth, Coalescence Behavior and its Simulation on Multi-Surface Cracks Under the Elevated Temperature

J. Ocean Eng. Technol. 1995;9(1):142-150.

고온하 복수 표면균열의 성장 합체거동과 시뮬레이션에 관한 연구

서창민,황남성,윤기봉

경북대학교 기계공학과,영남전문대학 기계과,한국표준과학연구원

Keywords: Multi-surface cracks, simulation program, fatigue life prediction, crack growgh, coalescence

핵심용어: 복수표면균열, 시뮬레이션 프로그램, 피로수명예측, 균열성장, 합체

Abstract

A simulation program concerned with multi-surface fatigue cracks which initiated at the semi-circular surface notches has been developed to predict their growth and coalescence behaviors at the elevated temperature. Three kinds of coalescence models such as SPC(surface point connection), ASME and BSI(British Standards Institution) conditions were applied, and the results of the simulation were compared with those of the experiment. This simulation is able to enhance the reliance and integrity of structures especially under the elevated temperature which have lots of difficulties in experiments and applications. This shows that the simulation result has utility for fatigue life prediction. Even though all the specimens were the same shape, the error rate was increased in accordance with the applied stress to the specimen. Among the material constants C and m in the narrow band, the results applied upper values of the band to the simulation has shown quite small error compared with the experiment results.