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New J Testing Method Using Load-COD Curve for Circumferential Through-Wall Cracked Pipes under Bending

하중-균열열림변위를 이용한 굽힘하중이 작용하는 원주방향 관통균열 배관의 새로운 J 실험법

  • Published : 2006.01.01

Abstract

The present paper provides experimental J estimation equation for the circumferential through-wall cracked pipe under four-point bending, based on the load-crack opening displacement (COD) record. Based on the limit analysis and the kinematically admissible rigid-body rotation field, the plastic ${\eta}$-factor for the load-COD record is derived and is compared with that for the load-load line displacement record. Comparison with the J results from detailed elastic-plastic finite element (FE) analysis shows that the proposed method based on the load-COD record provides reliable J estimates even for shallow cracks, whereas the conventional approach based on the load-load line displacement record gives erroneous results for shallow cracks. Thus, the proposed J estimation method could be recommended for testing the circumferential through-wall cracked pipe, particularly with shallow cracks.

Keywords

Circumferential Through-Wall Crack;Crack Opening Displacement;J-Testing

References

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