This paper presents a feasibility assessment of eliminating the protector of an electric submersi... more This paper presents a feasibility assessment of eliminating the protector of an electric submersible pump (ESP) by transferring the torque from the motor to the pump using a magnetic coupling, thereby allowing the motor to be hermetically sealed from the wellbore fluids in the operating environment. The paper also briefly discusses means of handling the motor oil expansion as well as the pump axial thrust. The industry seeks to enhance ESP reliability by designing protectorless ESPs. This requires new techniques to handle torque transfer, motor oil volume change and pump axial thrust, critical functions that a typical protector section performs. Magnetic coupling is a potential method to handle motor/pump torque transfer. For ESP applications, a radial magnetic flux type of coupling is considered. Finite Element software is used to identify the appropriate magnet materials, estimate the coupling dimensions, and predict the coupling performance under transient loads. A sensitivity st...
International Journal of Structural Stability and Dynamics
The vibration analysis of composite pipes with internal wall defects due to erosion-induced surfa... more The vibration analysis of composite pipes with internal wall defects due to erosion-induced surface degradation is investigated. The surface defects are treated as discontinuities. The geometry of the discontinuity is permitted to vary within the cross-section both in the angular and radial directions, and to occupy any length of the pipe span. A B-spline wavelet-based finite element method (BWFEM) that takes advantage of the localization properties of wavelets is invoked; thus utilizing its effectiveness in modeling of crack problems and local damages. The composite pipe was treated as beam elements that obey the Euler–Bernoulli beam theory. Unlike the conventional finite element method (FEM), the developed BWFEM uses fewer elements without compromising the accuracy. Numerical simulations are performed to demonstrate the accuracy and efficiency of the developed element through comparison with available results in the literature, as well as results obtained using ANSYS. Some benchma...
Journal of Pipeline Systems Engineering and Practice, 2012
ABSTRACT Acoustic leak-detection techniques are proven to be effective and have been widely used ... more ABSTRACT Acoustic leak-detection techniques are proven to be effective and have been widely used in water-distribution systems for several decades. Most of the existing acoustic leak-detection techniques rely on external measurements of sound emitted from the turbulent jet of water escaping the pipe. Direct acoustic measurements through hydrophones, which travel inside the pipe with the flow, have been recently addressed as an efficient complementary leak-detection technique. This paper presents an experimental investigation that addresses the feasibility and potential of in-pipe acoustic measurements for leak detection. An experimental test rig was constructed to simulate a water transmission pipeline and permits different leak sizes, flow rates, and pressures. The acquired acoustic signals were analyzed; the feasibility and limitations of invoking in-pipe measurements for leak detection were addressed.
A method for the dynamic analysis of multibody systems with impact is developed. The method accou... more A method for the dynamic analysis of multibody systems with impact is developed. The method accounts for oblique impacts and the effects of friction at the impacting surfaces provided that the two impacting bodies are rigid and executing plane motion. Equations of motion are written in the Lagrangian formulation using a mixed set of reference and elastic generalized coordinates. Impulse momentum relations including all bodies in the system are formulated and solved to account for the jump discontinuities in the system velocities and reaction forces due to impact based on estimated values of the coefficient of restitution and coefficient of dynamic friction. The method is applied to a multibody system and numerical results are presented to demonstrate the analysis scheme developed.
The natural frequencies of vibration of a rotating tapered beam with tip mass are investigated. E... more The natural frequencies of vibration of a rotating tapered beam with tip mass are investigated. Explicit expressions for the finite element mass and stiffness matrices are derived by using a consistent mass formulation. The beam is assumed to be linearly tapered in two planes. The generalized eigenvalue problem is defined and numerical solutions are generated for a wide range of rotational speed and tip mass variations. Both fixed and hinged end conditions are considered. Comparisons are made, whenever possible, with exact solutions and numerical results available in the literature. The results display high accuracy when compared with the exact solutions.
Impulsive responses often arise in mechanical systems due to collision, impact, joint clearances,... more Impulsive responses often arise in mechanical systems due to collision, impact, joint clearances, machine tool interaction, and material handling processes. Impulsive events take place during very short-lived intervals, and are normally associated with redistribution of momentum. The redistribution of momentum may take place instantaneously or during a very short interval, thus giving rise to discontinuities in the system's velocities. In this context, two modeling approaches are presented. The first approach adopts a smooth representation over the short-lived interval. In this case, the impulsive event is modeled while taking into consideration the mechanics of the contacting bodies. The second is a discontinuous dynamic model, in which the impulsive event is assumed to take place at an instant of time. The corresponding instantaneous redistribution of momentum results in jump discontinuities in the system's velocities, which are calculated to update the system state vector...
This technical note addresses an issue related to teaching mechanics of machines, specifically ab... more This technical note addresses an issue related to teaching mechanics of machines, specifically about the mobility calculations involving gear trains. In this context, we discuss the different interpretations of the constraints associated with the gear-pair contact or roll-pair contact. The conflicting interpretations of this kinematic pair are clarified and the label "gear joint" is redefined.
Volume 12: Vibration, Acoustics and Wave Propagation, 2012
ABSTRACT Identification and localization of leaks in water pipelines using acoustic methods have ... more ABSTRACT Identification and localization of leaks in water pipelines using acoustic methods have been utilized for many years. Most of the existing acoustic leak detection techniques rely on external measurements of sound emitted from the turbulent jet of water escaping the pipe. Direct acoustic measurements via hydrophones, which travel inside the pipe with the flow, have been recently addressed as a viable complementary leak detection technique. This paper presents an experimental investigation that addresses the feasibility and potential of inpipe acoustic measurements for leak detection. An experimental water pipe circuit was constructed to permit different line pressures, flow rates and leak sizes. The leak acoustic signature was acquired at different proximities from the leak port for variations of the line parameters. The acquired acoustic signals are processed and analyzed to access the feasibility and point out the limitations of invoking in-pipe measurements for leak detection.
Journal of Computational and Nonlinear Dynamics, 2012
This paper appraises the current status of research devoted to the problem of modeling impact in ... more This paper appraises the current status of research devoted to the problem of modeling impact in multibody systems. The paper presents a focused, yet coherent overview of the problem of modeling impulsive motions initiated by impacts in multibody systems in light of the reported literature, while highlighting the key research accomplishments, unresolved problems, and pending challenges. The paper begins with a brief overview of the mechanics of contact in two-body collisions, and then proceeds to review different approaches for modeling the dynamics of impact in rigid multibody mechanical systems and multibody systems of interconnected rigid and flexible bodies. The review concludes by shedding light on some pertinent computational considerations.
International Journal of Modelling and Simulation, 2010
ABSTRACT Impulsive responses often arise in mechanical systems due to col-lision, impact, joint c... more ABSTRACT Impulsive responses often arise in mechanical systems due to col-lision, impact, joint clearances, machine tool interaction, and ma-terial handling processes. Impulsive events take place during very short-lived intervals, and are normally associated with redistribution of momentum. The redistribution of momentum may take place instantaneously or during a very short interval, thus giving rise to discontinuities in the system's velocities. In this context, two mod-elling approaches are presented. The first approach adopts a smooth representation over the short-lived interval. In this case, the impul-sive event is modelled while taking into consideration the mechanics of the contacting bodies. The second is a discontinuous dynamic model, in which the impulsive event is assumed to take place at an instant of time. The corresponding instantaneous redistribution of momentum results in jump discontinuities in the system's velocities, which are calculated to update the system state vector for starting the next interval. The merits of the two modelling approaches are stated in the light of numerical simulations.
Flexible rotor balancing, in general, relies to a great extent on physical insight into the modal... more Flexible rotor balancing, in general, relies to a great extent on physical insight into the modal nature of the unbalance response. The objective of this investigation is to develop a hybrid experimental/analytical technique for balancing high-speed flexible rotors. The developed technique adopts an approach that combines the finite element modeling, experimental modal analysis, vibration measurements, and mathematical identification. The modal imbalances are identified and then transformed to the nodal space, in order to determine a set of physical balancing masses at some selected correction planes. The developed method does not rely on trial runs. In addition, the method does not require operating the supercritical rotor in a high-speed balancing facility, while accounting for the contribution of higher significant modes. The developed scheme is applied to a multidisk, multibearing, high-speed flexible rotor, where the interaction between the rotor-bending operating deflections a...
... AA SHABANA 1985 Computers and Structures 20, 737-744. Substructure synthesis methods for dyna... more ... AA SHABANA 1985 Computers and Structures 20, 737-744. Substructure synthesis methods for dynamic analysis of multi-body systems. 20. Y. KHULIEF and A. SH BANA 1984 American Society of Mechanical Engineers, Journal of Mechanisms, Transmission and Automation ...
This paper presents a feasibility assessment of eliminating the protector of an electric submersi... more This paper presents a feasibility assessment of eliminating the protector of an electric submersible pump (ESP) by transferring the torque from the motor to the pump using a magnetic coupling, thereby allowing the motor to be hermetically sealed from the wellbore fluids in the operating environment. The paper also briefly discusses means of handling the motor oil expansion as well as the pump axial thrust. The industry seeks to enhance ESP reliability by designing protectorless ESPs. This requires new techniques to handle torque transfer, motor oil volume change and pump axial thrust, critical functions that a typical protector section performs. Magnetic coupling is a potential method to handle motor/pump torque transfer. For ESP applications, a radial magnetic flux type of coupling is considered. Finite Element software is used to identify the appropriate magnet materials, estimate the coupling dimensions, and predict the coupling performance under transient loads. A sensitivity st...
International Journal of Structural Stability and Dynamics
The vibration analysis of composite pipes with internal wall defects due to erosion-induced surfa... more The vibration analysis of composite pipes with internal wall defects due to erosion-induced surface degradation is investigated. The surface defects are treated as discontinuities. The geometry of the discontinuity is permitted to vary within the cross-section both in the angular and radial directions, and to occupy any length of the pipe span. A B-spline wavelet-based finite element method (BWFEM) that takes advantage of the localization properties of wavelets is invoked; thus utilizing its effectiveness in modeling of crack problems and local damages. The composite pipe was treated as beam elements that obey the Euler–Bernoulli beam theory. Unlike the conventional finite element method (FEM), the developed BWFEM uses fewer elements without compromising the accuracy. Numerical simulations are performed to demonstrate the accuracy and efficiency of the developed element through comparison with available results in the literature, as well as results obtained using ANSYS. Some benchma...
Journal of Pipeline Systems Engineering and Practice, 2012
ABSTRACT Acoustic leak-detection techniques are proven to be effective and have been widely used ... more ABSTRACT Acoustic leak-detection techniques are proven to be effective and have been widely used in water-distribution systems for several decades. Most of the existing acoustic leak-detection techniques rely on external measurements of sound emitted from the turbulent jet of water escaping the pipe. Direct acoustic measurements through hydrophones, which travel inside the pipe with the flow, have been recently addressed as an efficient complementary leak-detection technique. This paper presents an experimental investigation that addresses the feasibility and potential of in-pipe acoustic measurements for leak detection. An experimental test rig was constructed to simulate a water transmission pipeline and permits different leak sizes, flow rates, and pressures. The acquired acoustic signals were analyzed; the feasibility and limitations of invoking in-pipe measurements for leak detection were addressed.
A method for the dynamic analysis of multibody systems with impact is developed. The method accou... more A method for the dynamic analysis of multibody systems with impact is developed. The method accounts for oblique impacts and the effects of friction at the impacting surfaces provided that the two impacting bodies are rigid and executing plane motion. Equations of motion are written in the Lagrangian formulation using a mixed set of reference and elastic generalized coordinates. Impulse momentum relations including all bodies in the system are formulated and solved to account for the jump discontinuities in the system velocities and reaction forces due to impact based on estimated values of the coefficient of restitution and coefficient of dynamic friction. The method is applied to a multibody system and numerical results are presented to demonstrate the analysis scheme developed.
The natural frequencies of vibration of a rotating tapered beam with tip mass are investigated. E... more The natural frequencies of vibration of a rotating tapered beam with tip mass are investigated. Explicit expressions for the finite element mass and stiffness matrices are derived by using a consistent mass formulation. The beam is assumed to be linearly tapered in two planes. The generalized eigenvalue problem is defined and numerical solutions are generated for a wide range of rotational speed and tip mass variations. Both fixed and hinged end conditions are considered. Comparisons are made, whenever possible, with exact solutions and numerical results available in the literature. The results display high accuracy when compared with the exact solutions.
Impulsive responses often arise in mechanical systems due to collision, impact, joint clearances,... more Impulsive responses often arise in mechanical systems due to collision, impact, joint clearances, machine tool interaction, and material handling processes. Impulsive events take place during very short-lived intervals, and are normally associated with redistribution of momentum. The redistribution of momentum may take place instantaneously or during a very short interval, thus giving rise to discontinuities in the system's velocities. In this context, two modeling approaches are presented. The first approach adopts a smooth representation over the short-lived interval. In this case, the impulsive event is modeled while taking into consideration the mechanics of the contacting bodies. The second is a discontinuous dynamic model, in which the impulsive event is assumed to take place at an instant of time. The corresponding instantaneous redistribution of momentum results in jump discontinuities in the system's velocities, which are calculated to update the system state vector...
This technical note addresses an issue related to teaching mechanics of machines, specifically ab... more This technical note addresses an issue related to teaching mechanics of machines, specifically about the mobility calculations involving gear trains. In this context, we discuss the different interpretations of the constraints associated with the gear-pair contact or roll-pair contact. The conflicting interpretations of this kinematic pair are clarified and the label "gear joint" is redefined.
Volume 12: Vibration, Acoustics and Wave Propagation, 2012
ABSTRACT Identification and localization of leaks in water pipelines using acoustic methods have ... more ABSTRACT Identification and localization of leaks in water pipelines using acoustic methods have been utilized for many years. Most of the existing acoustic leak detection techniques rely on external measurements of sound emitted from the turbulent jet of water escaping the pipe. Direct acoustic measurements via hydrophones, which travel inside the pipe with the flow, have been recently addressed as a viable complementary leak detection technique. This paper presents an experimental investigation that addresses the feasibility and potential of inpipe acoustic measurements for leak detection. An experimental water pipe circuit was constructed to permit different line pressures, flow rates and leak sizes. The leak acoustic signature was acquired at different proximities from the leak port for variations of the line parameters. The acquired acoustic signals are processed and analyzed to access the feasibility and point out the limitations of invoking in-pipe measurements for leak detection.
Journal of Computational and Nonlinear Dynamics, 2012
This paper appraises the current status of research devoted to the problem of modeling impact in ... more This paper appraises the current status of research devoted to the problem of modeling impact in multibody systems. The paper presents a focused, yet coherent overview of the problem of modeling impulsive motions initiated by impacts in multibody systems in light of the reported literature, while highlighting the key research accomplishments, unresolved problems, and pending challenges. The paper begins with a brief overview of the mechanics of contact in two-body collisions, and then proceeds to review different approaches for modeling the dynamics of impact in rigid multibody mechanical systems and multibody systems of interconnected rigid and flexible bodies. The review concludes by shedding light on some pertinent computational considerations.
International Journal of Modelling and Simulation, 2010
ABSTRACT Impulsive responses often arise in mechanical systems due to col-lision, impact, joint c... more ABSTRACT Impulsive responses often arise in mechanical systems due to col-lision, impact, joint clearances, machine tool interaction, and ma-terial handling processes. Impulsive events take place during very short-lived intervals, and are normally associated with redistribution of momentum. The redistribution of momentum may take place instantaneously or during a very short interval, thus giving rise to discontinuities in the system's velocities. In this context, two mod-elling approaches are presented. The first approach adopts a smooth representation over the short-lived interval. In this case, the impul-sive event is modelled while taking into consideration the mechanics of the contacting bodies. The second is a discontinuous dynamic model, in which the impulsive event is assumed to take place at an instant of time. The corresponding instantaneous redistribution of momentum results in jump discontinuities in the system's velocities, which are calculated to update the system state vector for starting the next interval. The merits of the two modelling approaches are stated in the light of numerical simulations.
Flexible rotor balancing, in general, relies to a great extent on physical insight into the modal... more Flexible rotor balancing, in general, relies to a great extent on physical insight into the modal nature of the unbalance response. The objective of this investigation is to develop a hybrid experimental/analytical technique for balancing high-speed flexible rotors. The developed technique adopts an approach that combines the finite element modeling, experimental modal analysis, vibration measurements, and mathematical identification. The modal imbalances are identified and then transformed to the nodal space, in order to determine a set of physical balancing masses at some selected correction planes. The developed method does not rely on trial runs. In addition, the method does not require operating the supercritical rotor in a high-speed balancing facility, while accounting for the contribution of higher significant modes. The developed scheme is applied to a multidisk, multibearing, high-speed flexible rotor, where the interaction between the rotor-bending operating deflections a...
... AA SHABANA 1985 Computers and Structures 20, 737-744. Substructure synthesis methods for dyna... more ... AA SHABANA 1985 Computers and Structures 20, 737-744. Substructure synthesis methods for dynamic analysis of multi-body systems. 20. Y. KHULIEF and A. SH BANA 1984 American Society of Mechanical Engineers, Journal of Mechanisms, Transmission and Automation ...
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