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Lie Seng Tjhen - One of the best experts on this subject based on the ideXlab platform.

  • Parametric Equation of stress intensity factor for tubular k joint under balanced axial loads
    International Journal of Fatigue, 2005
    Co-Authors: Shao Yongbo, Lie Seng Tjhen
    Abstract:

    In this paper, an automatic mesh generation method, which is for a uni-planar tubular K-joint containing an arbitrary surface crack located along the chord weld toe, is developed for producing the complete finite element mesh model. Using the proposed model, the stress intensity factors along the crack front have been evaluated by an interaction J-integral method in this study. To evaluate the reliability and accuracy of the numerical stress intensity factor results, a full-scale K-joint specimen was tested to failure. Using alternating current potential drop (ACPD) technique, the crack growth rate is captured and the stress intensity factors of the specimen are obtained using Paris' Equation. It has been found that numerical stress intensity factor results agree with experimental results quite well. Thereafter, altogether 5120 numerical models of tubular K-joints containing a surface crack at the crown subjected to balanced axial loads have been analyzed. A Parametric stress intensity factor Equation has then been proposed. The accuracy of the proposed stress intensity factor Equation has been assessed by comparing the computing results from the Equation with the numerical results. Error analysis has been conducted and it shows that the proposed Equation can provide reliable and accurate estimation of stress intensity factor for cracked tubular K-joints under balanced axial loads.

Shao Yongbo - One of the best experts on this subject based on the ideXlab platform.

  • Parametric Equation of stress intensity factor for tubular k joint under balanced axial loads
    International Journal of Fatigue, 2005
    Co-Authors: Shao Yongbo, Lie Seng Tjhen
    Abstract:

    In this paper, an automatic mesh generation method, which is for a uni-planar tubular K-joint containing an arbitrary surface crack located along the chord weld toe, is developed for producing the complete finite element mesh model. Using the proposed model, the stress intensity factors along the crack front have been evaluated by an interaction J-integral method in this study. To evaluate the reliability and accuracy of the numerical stress intensity factor results, a full-scale K-joint specimen was tested to failure. Using alternating current potential drop (ACPD) technique, the crack growth rate is captured and the stress intensity factors of the specimen are obtained using Paris' Equation. It has been found that numerical stress intensity factor results agree with experimental results quite well. Thereafter, altogether 5120 numerical models of tubular K-joints containing a surface crack at the crown subjected to balanced axial loads have been analyzed. A Parametric stress intensity factor Equation has then been proposed. The accuracy of the proposed stress intensity factor Equation has been assessed by comparing the computing results from the Equation with the numerical results. Error analysis has been conducted and it shows that the proposed Equation can provide reliable and accurate estimation of stress intensity factor for cracked tubular K-joints under balanced axial loads.

Jianhua Rao - One of the best experts on this subject based on the ideXlab platform.

  • identification for sucker rod pumping system s damping coefficients based on chain code method of pattern recognition
    Journal of Vibration and Acoustics, 2007
    Co-Authors: Hongzhao Liu, Bai Xi Liu, Daning Yuan, Jianhua Rao
    Abstract:

    In this paper, a method for identifying the damping coefficients of a directional well sucker-rod pumping system is put forward by means of the chain code method of pattern recognition. The 24-directional chain code is provided to encode the dynamometer card curve. The Parametric Equation of the dynamometer card curve is transformed into Fourier series whose coefficients can be computed according to the curve's chain codes. By means of these coefficients, shape characteristics of the curve are extracted. The Euclidean distance is introduced as the measurement of similar degree between the shape characteristics of measured dynamometer card and that of simulated dynamometer card. Changing the value of viscous damping coefficient and Coulomb friction coefficient in the simulation program, different simulated dynamometer cards are obtained. Substituting their shape characteristics to the Euclidean distance, respectively, a series of distances are acquired. When the distance is less than the given error, the corresponding values of the damping coefficients in the simulation program are regarded as real damping coefficients of the sucker-rod pumping system of directional well. In the end, an example is provided to show the correctness and effectiveness of the presented method.

  • Identification for Sucker-Rod Pumping System’s Damping Coefficients Based on Chain Code Method of Pattern Recognition
    Journal of Vibration and Acoustics, 2007
    Co-Authors: Hongzhao Liu, Bai Xi Liu, Daning Yuan, Jianhua Rao
    Abstract:

    In this paper, a method for identifying the damping coefficients of a directional well sucker-rod pumping system is put forward by means of the chain code method of pattern recognition. The 24-directional chain code is provided to encode the dynamometer card curve. The Parametric Equation of the dynamometer card curve is transformed into Fourier series whose coefficients can be computed according to the curve's chain codes. By means of these coefficients, shape characteristics of the curve are extracted. The Euclidean distance is introduced as the measurement of similar degree between the shape characteristics of measured dynamometer card and that of simulated dynamometer card. Changing the value of viscous damping coefficient and Coulomb friction coefficient in the simulation program, different simulated dynamometer cards are obtained. Substituting their shape characteristics to the Euclidean distance, respectively, a series of distances are acquired. When the distance is less than the given error, the corresponding values of the damping coefficients in the simulation program are regarded as real damping coefficients of the sucker-rod pumping system of directional well. In the end, an example is provided to show the correctness and effectiveness of the presented method.

  • A New Recognition Method for Damping Coefficients of Rod Pumping System of Directional Well
    Volume 3: Dynamic Systems and Controls Symposium on Design and Analysis of Advanced Structures and Tribology, 2006
    Co-Authors: Bai Xi Liu, Hongzhao Liu, Daning Yuan, Jianhua Rao
    Abstract:

    In this paper, a pattern recognition method is put forward to identify damping coefficients of rod pumping system of directional well by using characteristics space mapping. The 24-direction chain code is presented to encode the curve of dynamometer card. The Parametric Equation of the dynamometer card curve is transformed into Fourier series whose coefficients can be computed according to the curve’s chain codes. By means of those Fourier coefficients, shape characteristics of the curve are extracted. Euclidean distance is introduced as the measurement of similar degree between the shape characteristics of measured dynamometer card and that of simulated dynamometer card. Changing the value of viscous damping coefficient and Coulomb damping coefficient in the simulation program, different simulated dynamometer cards are obtained. Substituting their shape characteristics to the Euclidean distance, respectively, a series of distances are acquired. When the distance is little than the given error, the corresponding values of the damping coefficients in the simulation program are regarded as real damping coefficients of the rod pumping system of directional well. In the end, an example is provided to show the correctness and effectiveness of the presented method.Copyright © 2006 by ASME

A. B. Kaplun - One of the best experts on this subject based on the ideXlab platform.

O. S. Dutova - One of the best experts on this subject based on the ideXlab platform.