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Deric John Oehlers - One of the best experts on this subject based on the ideXlab platform.
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Plate end debonding in the constant Bending Moment zone of plated beams
Composites Part B-engineering, 2012Co-Authors: Vigneswaran Narayanamurthy, Jian Fei Chen, J. Cairns, Deric John OehlersAbstract:Abstract Reinforced concrete (RC) beams strengthened in flexure by externally bonding fibre reinforced polymer (FRP) or steel plate on their tension face are susceptible to premature plate end debonding failures. Safe design of such a strengthened RC beam demands a reliable and predictive debonding strength model. There are two special cases of plate end debonding failures: flexural debonding for cases when the plate terminates within a constant Bending Moment region (CMR), and shear debonding for the case when the plate terminates where the shear force is large but the Bending Moment is minimal. A general plate end debonding case is usually considered as an interaction between these two special cases. This paper is concerned with flexural debonding. A brief review of existing models is presented before the plate end interfacial stresses are examined. Three new models with different levels of accuracy are then developed: a closed-form theoretical model based on a simplified interfacial fracture mechanics analysis; a semi-empirical model; and a wholly empirical model. These three models together with two existing models are assessed against a carefully constructed test database containing 67 test data from an extensive literature survey.
Vahraz Nikzad - One of the best experts on this subject based on the ideXlab platform.
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plastic Bending Moment capacity of pipelines strain hardened elastic plastic approach
Journal of Pipeline Engineering, 2016Co-Authors: Vahraz NikzadAbstract:Offshore pipeline systems are designed to tolerate Bending Moment and axial tension / compression. New methodologies allow such systems to withstand controlled plasticity to some extent. It is important to refine the theoretical approaches when dealing with limit state design methodologies. This paper addresses the plastic Bending Moment capacity of pipes assuming pipe elastic-plastic behavior. In this regard, the governing equations of pipe Bending phenomena are derived and presented. Unlike the conventional elastic-perfect plastic approach, the stress-strain behavior of pipe is based on more accurate elastic-plastic relationship. It includes the strain hardening which has been neglected in conventional methodologies. The results of the analytical formulation are also compared with FE to support this methodology. Furthermore, a method to discretize the equations are presented that can be easily utilized based on project specific data in calculation spreadsheets. Results prove that there will be underestimation in plastic Bending Moment capacity of some large diameter stiff pipes when adopting conventional formulas. This can potentially affect the decisions which should be made in early stages of projects selection phase, thus, it is recommended to use more accurate methodology which is described in this paper.
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plastic Bending Moment capacity of pipelines strain hardened elastic plastic approach
Journal of Pipeline Engineering, 2016Co-Authors: Vahraz NikzadAbstract:Offshore pipeline systems are designed to tolerate Bending Moment and axial tension / compression. New methodologies allow such systems to withstand controlled plasticity to some extent. It is important to refine the theoretical approaches when dealing with limit state design methodologies. This paper addresses the plastic Bending Moment capacity of pipes assuming pipe elastic-plastic behavior. In this regard, the governing equations of pipe Bending phenomena are derived and presented. Unlike the conventional elastic-perfect plastic approach, the stress-strain behavior of pipe is based on more accurate elastic-plastic relationship. It includes the strain hardening which has been neglected in conventional methodologies. The results of the analytical formulation are also compared with FE to support this methodology. Furthermore, a method to discretize the equations are presented that can be easily utilized based on project specific data in calculation spreadsheets. Results prove that there will be underestimation in plastic Bending Moment capacity of some large diameter stiff pipes when adopting conventional formulas. This can potentially affect the decisions which should be made in early stages of projects selection phase, thus, it is recommended to use more accurate methodology which is described in this paper.
Vigneswaran Narayanamurthy - One of the best experts on this subject based on the ideXlab platform.
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Plate end debonding in the constant Bending Moment zone of plated beams
Composites Part B-engineering, 2012Co-Authors: Vigneswaran Narayanamurthy, Jian Fei Chen, J. Cairns, Deric John OehlersAbstract:Abstract Reinforced concrete (RC) beams strengthened in flexure by externally bonding fibre reinforced polymer (FRP) or steel plate on their tension face are susceptible to premature plate end debonding failures. Safe design of such a strengthened RC beam demands a reliable and predictive debonding strength model. There are two special cases of plate end debonding failures: flexural debonding for cases when the plate terminates within a constant Bending Moment region (CMR), and shear debonding for the case when the plate terminates where the shear force is large but the Bending Moment is minimal. A general plate end debonding case is usually considered as an interaction between these two special cases. This paper is concerned with flexural debonding. A brief review of existing models is presented before the plate end interfacial stresses are examined. Three new models with different levels of accuracy are then developed: a closed-form theoretical model based on a simplified interfacial fracture mechanics analysis; a semi-empirical model; and a wholly empirical model. These three models together with two existing models are assessed against a carefully constructed test database containing 67 test data from an extensive literature survey.
Guedes C Soares - One of the best experts on this subject based on the ideXlab platform.
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analysis of vertical Bending Moment on an ultra large containership induced by extreme head seas
ASME 2014 33rd International Conference on Ocean Offshore and Arctic Engineering, 2014Co-Authors: Suresh Rajendran, Nuno Fonseca, Guedes C SoaresAbstract:This paper discusses the numerical analysis of an ultra large containership model in severe head seas. A body nonlinear time domain code based on the strip theory is used for the calculation of the rigid body response of the vessel. The radiation, diffraction, Froude-krylov and hydrostatic forces are calculated for the exact wetted surface area of the ship at each time step. A practical engineering approach is followed to calculate the body nonlinear radiation and diffraction forces. The numerical vertical Bending Moment is compared with the experimental results. The experiment was conducted on a flexible model in both regular and irregular waves. The model comprised six segments that were joined with an aluminum backbone of variable stiffness characteristics in order to replicate the hydroelastic behavior of the real ship. The model was tested for two ship speeds, 15 and 22 knots. For the first three harmonic values of the vertical Bending Moment, a good agreement between the numerical and the experimental results are found. However, higher harmonics significantly contributed to the total experimental vertical Bending Moment, in regular waves with 8m wave height and a ship speed of 15 knots. Similarly, the value of the fourth harmonic was 32% of the first harmonic values when the ship encountered a 5m regular wave with 22 knots speed. On comparison of the rigid body response in irregular seas, the hydroelastic loads resulted in 49% increase in the maximum value of the vertical Bending Moment.© 2014 ASME
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strength assessment of a severely corroded box girder subjected to Bending Moment
Journal of Constructional Steel Research, 2014Co-Authors: S Saadeldeen, Yordan Garbatov, Guedes C SoaresAbstract:Abstract This work deals with the evaluation of the ultimate Bending Moment of a severely corroded box girder subjected to uniform vertical Bending Moment through a series of nonlinear finite element analysis. Two models of corrosion degradation have been adopted, one is an average general corrosion thickness reduction, and the other is the real thickness of the corroded plates. New stress–strain relations have been developed to account for the effect of corrosion on the flexural rigidity. To validate the new developed stress–strain relationships, a comparison between the finite element analysis results using the existing stress–strain models, the newly developed ones and the experimental test results of a severely corroded box girder have been conducted. The comparison showed a good agreement and supported the choice of the newly developed stress–strain relationships of corroded structures.
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experimental evaluation of the behaviour of a mild steel box girder under Bending Moment
Ships and Offshore Structures, 2008Co-Authors: J M Gordo, Guedes C SoaresAbstract:An experimental evaluation of a mild steel box girder subjected to a pure Bending Moment is presented. The Moment–curvature curves are presented allowing for the analysis of elastic–plastic behaviour until collapse, the evaluation of the ultimate Bending Moment and post-collapse behaviour. The residual stress relief during loading and unloading path is also analysed. The results are compared with a test on a similar box girder made of high-tensile steel. The effects of residual stresses on the behaviour of the box girder are analysed using a progressive collapse method for structures under longitudinal Bending Moment.
Jian Fei Chen - One of the best experts on this subject based on the ideXlab platform.
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Plate end debonding in the constant Bending Moment zone of plated beams
Composites Part B-engineering, 2012Co-Authors: Vigneswaran Narayanamurthy, Jian Fei Chen, J. Cairns, Deric John OehlersAbstract:Abstract Reinforced concrete (RC) beams strengthened in flexure by externally bonding fibre reinforced polymer (FRP) or steel plate on their tension face are susceptible to premature plate end debonding failures. Safe design of such a strengthened RC beam demands a reliable and predictive debonding strength model. There are two special cases of plate end debonding failures: flexural debonding for cases when the plate terminates within a constant Bending Moment region (CMR), and shear debonding for the case when the plate terminates where the shear force is large but the Bending Moment is minimal. A general plate end debonding case is usually considered as an interaction between these two special cases. This paper is concerned with flexural debonding. A brief review of existing models is presented before the plate end interfacial stresses are examined. Three new models with different levels of accuracy are then developed: a closed-form theoretical model based on a simplified interfacial fracture mechanics analysis; a semi-empirical model; and a wholly empirical model. These three models together with two existing models are assessed against a carefully constructed test database containing 67 test data from an extensive literature survey.