• 제목/요약/키워드: J Estimation

검색결과 1,374건 처리시간 0.028초

하중-균열열림변위를 이용한 굽힘하중이 작용하는 원주방향 관통균열 배관의 새로운 J 실험법 (New J Testing Method Using Load-COD Curve for Circumferential Through-Wall Cracked Pipes under Bending)

  • 허남수;김윤재;김영진
    • 대한기계학회논문집A
    • /
    • 제30권1호
    • /
    • pp.60-65
    • /
    • 2006
  • 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.

Nonparametric Estimation of Reliabilityin Strength-Stress Model

  • Jeong, H.S.;Kim, J.J.;Park., B.U.;Lee, H.W.
    • Communications for Statistical Applications and Methods
    • /
    • 제3권3호
    • /
    • pp.187-194
    • /
    • 1996
  • We treat the problem of estimating reliability R = P[Y < X] in the stress-strength model in which a unit of strength X is subfected to enviromental stress Y./ In this paper several nonparametric approaches to estimation of R are analyzed and compared by simulations.

  • PDF

화력발전소 보일러 제어루프의 시뮬레이션에 관한 연구 (A Study of Boiler Control Loop Simulation in Thermal Power Plant)

  • 이주현;이찬주
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1999년도 하계학술대회 논문집 B
    • /
    • pp.868-870
    • /
    • 1999
  • In this paper we obtain a discrete mathmatical model of a Boiler control system from expermental data, we find appropriate input signal and parameter estimation algorithm for identification of the Boiler control system in power plant. Under these conditions experimental data are collected from real system and parameters are estimated by the Recursive Least Square algorithm. The computer simulation results show the parameter estimation algorithm for identification and the effectiveness of controller design of the Boiler control system.

  • PDF

Estimation of Density via Local Polynomial Tegression

  • Park, B. U.;Kim, W. C.;J. Huh;J. W. Jeon
    • Journal of the Korean Statistical Society
    • /
    • 제27권1호
    • /
    • pp.91-100
    • /
    • 1998
  • A method of estimating probability density using regression tools is presented here. It is based on equal-length binning and locally weighted approximate likelihood for bin counts. The method is particularly useful for densities with bounded supports, where it automatically corrects edge effects without using boundary kernels.

  • PDF

배전계통 저압배전선 전압강하 추정방법 (Estimation of Voltage Drop in Low Voltage Distribution Line)

  • 김태응;김창순;김재언;손진만;박종근;노대석;김광호;조재형
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2002년도 하계학술대회 논문집 A
    • /
    • pp.118-120
    • /
    • 2002
  • Voltage drop of low voltage distribution line is closely related with proper voltage regulation. It depends on the voltage drop of pole transformer, low voltage distribution line, and low voltage customer entrance line. Using above voltage drop factors, we proposes an estimation method of voltage drop in low voltage distribution line. Proposed method has been applied to a 22.9kV practical distribution system.

  • PDF

J積分法 을 이용한 複合組織鋼 의 破壞靭性評價 (Estimation of Fracture Toughness of Dual Phase Steel by J Integral)

  • 김정규;오재민;이완익
    • 대한기계학회논문집
    • /
    • 제8권5호
    • /
    • pp.469-475
    • /
    • 1984
  • 본 연구에서는 구조물 경량화재료로서 변형거동이 현저히 다른 마르텐사이트 와 페라이트로 이루어진 복합조직강의 파괴인성에 관한 기본적 자료를 얻기 위하여 이 강을 모델재로서 준비하고 균열선단에서의 미시파괴기구 및 JSME Sool의 평가법을 이 용한 파괴인성에 대하여 검토하였다.

複合組織鋼의 破壞靭性 評價와 스트렛치죤의 特性 (Estimation of fracture toughness and characteristics of stretched zone formation in dual phase steel)

  • 김정규;오재민
    • 대한기계학회논문집
    • /
    • 제10권5호
    • /
    • pp.680-688
    • /
    • 1986
  • 본 연구에서는 마르텐사이트-페라이트 복합조직강의 파괴인성평가법을 확립하 기 위하여 불균질의 대표적 인자인 페라이트 결정입경 및 마르텐사이트의 강도를 변화 시켜 R곡선법과 SZ법에 의해 파괴인성을 평가하고, SZ법에 의한 $J_{IC}$ 의 과대평가 정 도와 이에 대한 원인을 규명하기 위하여 균열선단의 미시파괴거동을 검토하였다.

Chine형선(型船)의 상하진동(上下振動)에 대(對)한 가상관성계수(假想慣性係數)에 관(關)하여 (On the Virtual Inertia Coefficient of the Chine-type Ship in Vertical Vibration)

  • 김극천;김정제
    • 대한조선학회지
    • /
    • 제9권1호
    • /
    • pp.1-6
    • /
    • 1972
  • To contribute towards more accurate estimation of the virtual coefficient for the vertical vibration of the chine-type ship, experimentally obtained three-dimensional correction factors, J, of added mass of prismatic beams having cross section shape of hypotrocoid characters, slightly concaved Lewis form and elliptic form are investigated in connection with the applicability of an approximate analytical calculation method compared to that proposed by T. Kumai[6] for the Lewis form cylinders, and synthetically in compared with the experimental works on various cross section shapes of the other type by L.C. Burril et al[8] and the analytical works on the ellipsoid of revolution by F.M. Lewis[1] and J.L. Taylor[2]. The experimental results show that the aforementioned analytical method gives, unlike that for the Lewis form cylinders, considerably larger J-values for the chine-type cylinders, and that the influence of the character of the cross section shape on J-values is not remarkable in practical sense. Finally, considering in synthesis the experimental results on prismatic beams, the Burril's works on palabolic plan form and elliptic plan form, and that the chine-type ship usually has a hull form of transom stern, it is fairly safe to say, at the present stage, that adoptation of the Taylor's J-values will not results in any large error in estimation of the virtual inertia coefficients of the chine-type ships.

  • PDF