The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform

Bipul Chandra Mondal - One of the best experts on this subject based on the ideXlab platform.

  • Remaining strength assessment of deteriorating energy pipelines
    2018
    Co-Authors: Bipul Chandra Mondal
    Abstract:

    Pipelines are extensively used as the most economic means of transporting oil and gas. The steel pipelines have been widely used for these applications due to the high strength to weight ratio of the material, resulting in lower material cost. These pipelines are subjected to corrosions during the service life, resulting in the reduction of wall thicknesses. The prediction of the remaining strength of a corroded pipeline is required for fitness-for-purpose assessment. For the prediction of the remaining strength, different models were developed based on simplified results of analysis and/or empirical fits to limited experimental data which are expressed in terms of burst pressure. The established design codes adopt simplified design equations for the burst pressure prediction for corroded pipelines. However, the burst pressures predicted using the simplified equations are not consistent with the burst test results and results obtained from rigorous finite element (FE) analyses. Besides, the pipelines are often subjected to axial force and bending moment. The effects of the axial force and bending moment on the burst pressure are not rationally accounted. In this research, the axial forces and bending moments experience by energy pipelines are first examined considering a case of offshore pipelines. The improved burst pressure models are then developed for pipelines with and without the axial forces and bending moments. The existing models of burst pressures for deteriorated-steel pipelines are investigated to determine the contributing parameters to the burst pressures. The Folias Factor and flow stress are identified as the major parameters contributing to the burst pressures of the corroded pipelines. A detailed study, based on FE analysis using Abaqus, has been carried out to develop a new method of defining the Folias Factor and to develop an improved model for burst pressure prediction for a corroded pipeline. The finite element analysis is then extended to develop the new interaction rules for the pipelines subjected to multiple patches of the corrosion defects. The FE analysis is used to develop failure loci for burst pressure prediction for pipelines subjected to axial forces and bending moments. Corroded pipelines often suffer from the stress corrosion cracking (SCC) when the pipelines in corrosive environments are subjected to high tensile stresses. The SCC occurs at a stress intensity Factor well below the fracture toughness of the material. The effects of the SCC and the crack propagation in the deteriorating pipelines cannot be captured using standard FE modeling techniques. It is proposed to employ fracture mechanics to determine the remaining strengths of pipelines containing corrosion defects or crack-like defects or corrosion with crack-like defects.

  • Improved Folias Factor and Burst Pressure Models for Corroded Pipelines
    Journal of Pressure Vessel Technology-transactions of The Asme, 2017
    Co-Authors: Bipul Chandra Mondal, Ashutosh Sutra Dhar
    Abstract:

    Burst pressure models are used for the fitness-for-purpose assessment of energy pipelines. Existing burst pressure models for corroded pipelines are unable to predict the pipe capacity correctly. In this paper, an improved burst pressure model is developed for corroded pipelines considering the burst pressure of flawless pipes and a reduction Factor due to corrosion separately. The equation for the burst pressure of flawless pipe is revised based on the theory of the thick wall cylinder. A new model for the Folias Factor is proposed for calculating the reduction Factor. The new model for the Folias Factor incorporates the depth of corrosion defect, whereas the existing models do not account for the effect of the defect depth. The authors' earlier work revealed that the Folias Factor depends on the depth of defect. The proposed burst model reasonably predicts the burst pressures obtained from finite element (FE) analysis conducted in this study and the burst test results available in the published literature.

  • Finite-Element Evaluation of Burst Pressure Models for Corroded Pipelines
    Journal of Pressure Vessel Technology-transactions of The Asme, 2016
    Co-Authors: Bipul Chandra Mondal, Ashutosh Sutra Dhar
    Abstract:

    Codes/standards have been developed to calculate accurately the burst pressure for corroded pipelines. Five burst pressure models are evaluated in this paper using three-dimensional finite-element (FE) analysis. The finite-element models are validated using burst test results available in the literature. The design codes/standards are found to calculate variable burst pressures with respect to the finite-element calculations and the laboratory test results. The variability in the calculated burst pressures is attributed to the use of different flow stresses for the material and different burst pressure reduction Factors for the corroded geometry. The Folias Factor is considered as the major parameter contributing to the burst pressure reduction Factor. Three different equations are currently used to calculate the Folias Factor in the design codes that are expressed in terms of l2/(Dt). However, the finite-element evaluation presented here reveals that the Folias Factor also depends on other parameters such as the defect depth.

Ashutosh Sutra Dhar - One of the best experts on this subject based on the ideXlab platform.

  • Improved Folias Factor and Burst Pressure Models for Corroded Pipelines
    Journal of Pressure Vessel Technology-transactions of The Asme, 2017
    Co-Authors: Bipul Chandra Mondal, Ashutosh Sutra Dhar
    Abstract:

    Burst pressure models are used for the fitness-for-purpose assessment of energy pipelines. Existing burst pressure models for corroded pipelines are unable to predict the pipe capacity correctly. In this paper, an improved burst pressure model is developed for corroded pipelines considering the burst pressure of flawless pipes and a reduction Factor due to corrosion separately. The equation for the burst pressure of flawless pipe is revised based on the theory of the thick wall cylinder. A new model for the Folias Factor is proposed for calculating the reduction Factor. The new model for the Folias Factor incorporates the depth of corrosion defect, whereas the existing models do not account for the effect of the defect depth. The authors' earlier work revealed that the Folias Factor depends on the depth of defect. The proposed burst model reasonably predicts the burst pressures obtained from finite element (FE) analysis conducted in this study and the burst test results available in the published literature.

  • Finite-Element Evaluation of Burst Pressure Models for Corroded Pipelines
    Journal of Pressure Vessel Technology-transactions of The Asme, 2016
    Co-Authors: Bipul Chandra Mondal, Ashutosh Sutra Dhar
    Abstract:

    Codes/standards have been developed to calculate accurately the burst pressure for corroded pipelines. Five burst pressure models are evaluated in this paper using three-dimensional finite-element (FE) analysis. The finite-element models are validated using burst test results available in the literature. The design codes/standards are found to calculate variable burst pressures with respect to the finite-element calculations and the laboratory test results. The variability in the calculated burst pressures is attributed to the use of different flow stresses for the material and different burst pressure reduction Factors for the corroded geometry. The Folias Factor is considered as the major parameter contributing to the burst pressure reduction Factor. Three different equations are currently used to calculate the Folias Factor in the design codes that are expressed in terms of l2/(Dt). However, the finite-element evaluation presented here reveals that the Folias Factor also depends on other parameters such as the defect depth.

Xin Li - One of the best experts on this subject based on the ideXlab platform.

  • Determination of Folias Factor for Failure Pressure of Corroded Pipeline
    Journal of Pressure Vessel Technology-transactions of The Asme, 2020
    Co-Authors: Xin Li
    Abstract:

    Abstract Corrosion assessment and burst pressure prediction of line pipes with corrosion defects are essential for the integrity assessment of steel transmission pipelines. The failure assessment methods proposed in codes or handbooks may be overly conservative or exhibit significant scatter in their predictions. In this paper, the effects of two key parameters—the flow stress and Folias bulging Factor, on predicting the failure pressure of pipelines with defects are studied. The Folias bulging Factor is suggested by fitting the results from finite element (FE) analysis. Then, a new prediction method for the failure pressure of pipelines with defects is proposed. The failure pressures predicted by the proposed method are in better agreement with the experimental results than the results by the other methods such as B31G, MB31G, Det Norske Veritas (DNV), and rectangular parabolic area (RPA).

Liu Wu - One of the best experts on this subject based on the ideXlab platform.

  • Study of Burst Strength Assessment Method of the Gouge Defect on Pipeline
    Oil Field Equipment, 2020
    Co-Authors: Liu Wu
    Abstract:

    In the pipeline's construction phase and long-term operation time,there will be inevitable mechanical damage in the pipeline.The burst of mechanical damage in the pipeline is the main form of pipeline failure.Gouge is the main form of mechanical damage.Commonly use NG-18 formula for assessment of pipe gouge defects in international.Comparing various forms of NG-18 formula with the experimental results,it was educed that the flow stress was a main Factor of affecting the failure stress that NG-18 formula predict,and the combination of the Folias Factor in the revised ASME B31G standard and the mean flow stress was proximal to the actual situation,so it is a more ideal combination.

W. Stadtmüller - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of ductile vessel rupture by R-curve analysis using CT specimens and wide plate tests
    International Journal of Pressure Vessels and Piping, 2003
    Co-Authors: P. Julisch, W. Stadtmüller
    Abstract:

    Abstract A large volume, thin-walled vessel was weakened by the introduction of a longitudinal slit sealed from the inside. With the help of compact-tension specimens and wide plates, attempts were made to analyse the failure by means of elastic-plastic fracture mechanics, taking into account the bulging of the vessel by the use of the so-called ‘Folias Factor’. With J R curves obtained from wide plate tensile tests, the crack driving force curves provide stresses at crack initiation and instability which are approximately 20–30% below the corresponding values of the internal pressure test. With regard to stable crack growth, very good agreement was achieved.