In this work, we investigate the appearance of postresonance backward whirl (Po-BW) using the mod... more In this work, we investigate the appearance of postresonance backward whirl (Po-BW) using the model of a rotor with a breathing crack. This phenomenon could be employed as an indicator of crack and bearing damage in rotor systems that undergo recurrent passage through critical forward whirl rotational speed during startup and coast down operations. The finite element (FE) model is used to develop the linear-time-varying equations of motion of the considered accelerating cracked rotor. The whirl response is obtained by direct numerical integration. In addition, the effect of bearing anisotropy on Po-BW excitation is investigated. It is found that the appearance of Po-BW zones is significantly affected by the depth of the crack, angular acceleration rate, anisotropy of bearings, and the orientation of the unbalance force vector with respect to the crack opening direction. The full spectrum analysis (FSA) is also employed and found to be an efficient tool for identifying the Po-BW zone...
Low-carbon steel is widely used in industrial pipelines, and corrosion studies are focused mostly... more Low-carbon steel is widely used in industrial pipelines, and corrosion studies are focused mostly on erosion-corrosion, its prediction and control. In this paper, the corrosion rate in pipelines is modeled using a flow loop and measured by linear polarization resistance method (LPR) using a 3-electrode corrosion setup for API-5L-X65 QT steel. Optical microscopy and SEM studies are conducted to examine the surface of the sample and the corrosion products. The effect of NaCl concentration on the corrosion rate is studied at different pH, temperature range, and flow velocities with dissolved oxygen content in the solution maintained at 6 mg/L (6ppm). The corrosion rate is found to be varying from 1 mil per year (0.0254 mmyr−1) to 10 mils per year (0.254 mmyr−1), and the corrosion rate increases with the flow velocity and reaches a maximum at Reynolds Number above 10,000. Further increase in fluid velocity shows corrosion is flow insensitive, and uniform corrosion is predominant in the ...
Oil flowlines, the first “pipeline” system connected to the wellhead, are pipelines that are 5 to... more Oil flowlines, the first “pipeline” system connected to the wellhead, are pipelines that are 5 to 30.5 cm (two to twelve inches) in diameter, most susceptible to corrosion, and very difficult to inspect. Herein, an external corrosion detection sensor for oil and gas pipelines, consisting of a semicircular plastic strip, a flat dog-bone-shaped sacrificial metal plate made out of the same pipeline material, and an optical fiber with Fiber Bragg Grating (FBG) sensors, is described. In the actual application, multiple FBG optical fibers are attached to an oil and gas pipeline using straps or strips or very large hose clamps, and, every few meters, our proposed corrosion detection sensor will be glued to the FBG sensors. When the plastic parts are attached to the sacrificial metals, the plastic parts will be deformed and stressed; thus, placing the FBG sensors in tension. When corrosion is severe at any given pipeline location, the sacrificial metal at that location will corrode till fai...
This paper proposes an innovative solution to suppress torsional vibrations in any rotating machi... more This paper proposes an innovative solution to suppress torsional vibrations in any rotating machinery with a variable frequency of excitation, or a variable natural frequency. The adaptive torsional tuned vibration absorber (ATTVA) was designed using an integrated electromagnetic circuit, which can adapt its natural frequency to match the varying natural frequency of any Multi Degree of Freedom (MDOF) rotating system. A two degree of freedom rotating system was modeled along with the integrated ATTVA using the bond graph modeling technique. Simulation results showed that torsional vibrations can be easily attenuated by controlling the capacitance shunted to the voice coil circuit. The ATTVA was designed, fabricated and evaluated on a test rig in the laboratory. Test results revealed good matching between the mathematical model and the experimental data. Experiments were performed with different configurations of the ATTVA, and the experimental results showed reasonable suppression i...
Metastructures are viewed as a promising means for suppressing elastic waves and unwanted vibrati... more Metastructures are viewed as a promising means for suppressing elastic waves and unwanted vibrations. Metastructures comprise of elementary cells with embedded resonators, which act as vibration absorbers. Design and frequency tuning of individual resonators inside the metastructure allows to achieve effective suppression of vibrations over a relatively wide frequency bandwidth, which makes metastructures superior compared to conventional passive vibration absorbers. This paper describes numerical and experimental validation of a modeling tool for design of planar resonators with elastic elements arranged in a zigzag configuration for suppression of longitudinal vibrations. Zigzag topology is advantageous due to its ability to provide higher compliance within a limited space, so as to achieve low resonant frequencies. Natural frequencies predicted by the proposed model agree well with predictions provided by detailed finite element models and experimental measurements.
A monitoring solution was developed for detection of material loss in metals such as carbon steel... more A monitoring solution was developed for detection of material loss in metals such as carbon steel using the force generated by permanent magnets in addition to the optical strain sensing technology. The working principle of the sensing system is related to the change in thickness of a steel plate, which typically occurs due to corrosion. As thickness decreases, the magnetostatic force between the magnet and the steel structure also decreases. This, in turn, affects the strain measured using the optical fiber. The sensor prototype was designed and built after verifying its sensitivity using a numerical model. The prototype was tested on steel plates of different thicknesses to establish the relationship between the metal thickness and measured strain. The results of experiments and numerical models demonstrate a strong relationship between the metal thickness and the measured strain values.
External corrosion was identified as one of the main causes of pipeline failures worldwide. A sol... more External corrosion was identified as one of the main causes of pipeline failures worldwide. A solution that addresses the issue of detecting and quantifying corrosivity of environment for application to existing exposed pipelines has been developed. It consists of a sensing array made of an assembly of thin strips of pipeline steel and a circuit that provides a visual sensor reading to the operator. The proposed sensor is passive and does not require a constant power supply. Circuit design was validated through simulations and lab experiments. Accelerated corrosion experiment was conducted to confirm the feasibility of the proposed corrosivity sensor design.
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2016, 2016
In the oil and gas industry, pipeline integrity is a serious concern due to the consequences of p... more In the oil and gas industry, pipeline integrity is a serious concern due to the consequences of pipeline failure. External corrosion was identified as one of the main causes of pipeline failures worldwide. A solution that addresses the issue of detecting and quantifying corrosivity of environment for application to existing exposed pipelines has been developed. The proposed sensor consists of an electric circuit and a sensing array connected to the circuit. The sensing array is an assembly of strips made of a metal identical to that of the pipe, having the same length and width, but different thicknesses. The sensing array is exposed to the same environment as the pipe. As corrosion propagates in the metal strips of the array, it corrodes the metal until it finally breaks the metal strip apart resulting in a discontinuity in the circuit. The sensor circuit is energized using electromagnetic field, and its function is to indicate which strips in the array are fully corroded. Visual indication is provided to the operator via LEDs. The proposed sensor can be installed on existing pipelines without altering the pipe structure or disturbing the production process. It is passive and has low maintenance requirements. Circuit design was validated through lab experiments. Results obtained from experiments were consistent with simulation results.
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2016, 2016
Pipeline Inspection Gauges (PIGs) are used for internal corrosion inspection of oil pipelines eve... more Pipeline Inspection Gauges (PIGs) are used for internal corrosion inspection of oil pipelines every 3-5 years. However, between inspection intervals, rapid corrosion may occur, potentially resulting in major accidents. The motivation behind this research project was to develop a safe distributed corrosion sensor placed inside oil pipelines continuously monitoring corrosion. The intrinsically safe nature of light provided motivation for researching fiber optic sensors as a solution. The sensing fiber's cladding features polymer plastic that is chemically sensitive to hydrocarbons within crude oil mixtures. A layer of metal, used in the oil pipeline's construction, is deposited on the polymer cladding, which upon corrosion, exposes the cladding to surrounding hydrocarbons. The hydrocarbon's interaction with the cladding locally increases the cladding's refractive index in the radial direction. Light intensity of a traveling pulse is reduced due to local reduction in the modal capacity which is interrogated by Optical Time Domain Reflectometery. Backscattered light is captured in real-time while using time delay to resolve location, allowing real-time spatial monitoring of environmental internal corrosion within pipelines spanning large distances. Step index theoretical solutions were used to calculate the power loss due changes in the intensity profile. The power loss is translated into an attenuation coefficient characterizing the expected OTDR trace which was verified against similar experimental results from the literature. A laboratory scale experiment is being developed to assess the validity of the model and the practicality of the solution.
A strain based corrosion sensor for the detection of environmental corrosion of pre-stressed stru... more A strain based corrosion sensor for the detection of environmental corrosion of pre-stressed structures was developed and tested on mild steel specimens readily available. Theoretically, a beam shaped specimen under a displacement load exhibits a linear relationship between the strain observed at any point through the thickness of the beam cross-section. This property was exploited to detect thickness changes in pre-stressed mild steel specimens in a double bending configuration under an electrochemically excited corrosion reaction. The reaction was accelerated by supplying a DC current to the cell where the specimens act as anodes of the system, while graphite rods serve as cathodes. The strain was logged using fiber optic Bragg grating technology and conventional electrical strain gages simultaneously. Results show a strong relationship between the corrosion rate observed by back-calculation from supplied current and the time derivative of the measured strain values. Application of this sensor can therefore be extended to a variety of structures under mechanical loading, proving valuable for both its ability to measure corrosion rate in real-time, while maintaining an intrinsically safe nature appropriate by industrial standards.
In this work, we investigate the appearance of postresonance backward whirl (Po-BW) using the mod... more In this work, we investigate the appearance of postresonance backward whirl (Po-BW) using the model of a rotor with a breathing crack. This phenomenon could be employed as an indicator of crack and bearing damage in rotor systems that undergo recurrent passage through critical forward whirl rotational speed during startup and coast down operations. The finite element (FE) model is used to develop the linear-time-varying equations of motion of the considered accelerating cracked rotor. The whirl response is obtained by direct numerical integration. In addition, the effect of bearing anisotropy on Po-BW excitation is investigated. It is found that the appearance of Po-BW zones is significantly affected by the depth of the crack, angular acceleration rate, anisotropy of bearings, and the orientation of the unbalance force vector with respect to the crack opening direction. The full spectrum analysis (FSA) is also employed and found to be an efficient tool for identifying the Po-BW zone...
Low-carbon steel is widely used in industrial pipelines, and corrosion studies are focused mostly... more Low-carbon steel is widely used in industrial pipelines, and corrosion studies are focused mostly on erosion-corrosion, its prediction and control. In this paper, the corrosion rate in pipelines is modeled using a flow loop and measured by linear polarization resistance method (LPR) using a 3-electrode corrosion setup for API-5L-X65 QT steel. Optical microscopy and SEM studies are conducted to examine the surface of the sample and the corrosion products. The effect of NaCl concentration on the corrosion rate is studied at different pH, temperature range, and flow velocities with dissolved oxygen content in the solution maintained at 6 mg/L (6ppm). The corrosion rate is found to be varying from 1 mil per year (0.0254 mmyr−1) to 10 mils per year (0.254 mmyr−1), and the corrosion rate increases with the flow velocity and reaches a maximum at Reynolds Number above 10,000. Further increase in fluid velocity shows corrosion is flow insensitive, and uniform corrosion is predominant in the ...
Oil flowlines, the first “pipeline” system connected to the wellhead, are pipelines that are 5 to... more Oil flowlines, the first “pipeline” system connected to the wellhead, are pipelines that are 5 to 30.5 cm (two to twelve inches) in diameter, most susceptible to corrosion, and very difficult to inspect. Herein, an external corrosion detection sensor for oil and gas pipelines, consisting of a semicircular plastic strip, a flat dog-bone-shaped sacrificial metal plate made out of the same pipeline material, and an optical fiber with Fiber Bragg Grating (FBG) sensors, is described. In the actual application, multiple FBG optical fibers are attached to an oil and gas pipeline using straps or strips or very large hose clamps, and, every few meters, our proposed corrosion detection sensor will be glued to the FBG sensors. When the plastic parts are attached to the sacrificial metals, the plastic parts will be deformed and stressed; thus, placing the FBG sensors in tension. When corrosion is severe at any given pipeline location, the sacrificial metal at that location will corrode till fai...
This paper proposes an innovative solution to suppress torsional vibrations in any rotating machi... more This paper proposes an innovative solution to suppress torsional vibrations in any rotating machinery with a variable frequency of excitation, or a variable natural frequency. The adaptive torsional tuned vibration absorber (ATTVA) was designed using an integrated electromagnetic circuit, which can adapt its natural frequency to match the varying natural frequency of any Multi Degree of Freedom (MDOF) rotating system. A two degree of freedom rotating system was modeled along with the integrated ATTVA using the bond graph modeling technique. Simulation results showed that torsional vibrations can be easily attenuated by controlling the capacitance shunted to the voice coil circuit. The ATTVA was designed, fabricated and evaluated on a test rig in the laboratory. Test results revealed good matching between the mathematical model and the experimental data. Experiments were performed with different configurations of the ATTVA, and the experimental results showed reasonable suppression i...
Metastructures are viewed as a promising means for suppressing elastic waves and unwanted vibrati... more Metastructures are viewed as a promising means for suppressing elastic waves and unwanted vibrations. Metastructures comprise of elementary cells with embedded resonators, which act as vibration absorbers. Design and frequency tuning of individual resonators inside the metastructure allows to achieve effective suppression of vibrations over a relatively wide frequency bandwidth, which makes metastructures superior compared to conventional passive vibration absorbers. This paper describes numerical and experimental validation of a modeling tool for design of planar resonators with elastic elements arranged in a zigzag configuration for suppression of longitudinal vibrations. Zigzag topology is advantageous due to its ability to provide higher compliance within a limited space, so as to achieve low resonant frequencies. Natural frequencies predicted by the proposed model agree well with predictions provided by detailed finite element models and experimental measurements.
A monitoring solution was developed for detection of material loss in metals such as carbon steel... more A monitoring solution was developed for detection of material loss in metals such as carbon steel using the force generated by permanent magnets in addition to the optical strain sensing technology. The working principle of the sensing system is related to the change in thickness of a steel plate, which typically occurs due to corrosion. As thickness decreases, the magnetostatic force between the magnet and the steel structure also decreases. This, in turn, affects the strain measured using the optical fiber. The sensor prototype was designed and built after verifying its sensitivity using a numerical model. The prototype was tested on steel plates of different thicknesses to establish the relationship between the metal thickness and measured strain. The results of experiments and numerical models demonstrate a strong relationship between the metal thickness and the measured strain values.
External corrosion was identified as one of the main causes of pipeline failures worldwide. A sol... more External corrosion was identified as one of the main causes of pipeline failures worldwide. A solution that addresses the issue of detecting and quantifying corrosivity of environment for application to existing exposed pipelines has been developed. It consists of a sensing array made of an assembly of thin strips of pipeline steel and a circuit that provides a visual sensor reading to the operator. The proposed sensor is passive and does not require a constant power supply. Circuit design was validated through simulations and lab experiments. Accelerated corrosion experiment was conducted to confirm the feasibility of the proposed corrosivity sensor design.
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2016, 2016
In the oil and gas industry, pipeline integrity is a serious concern due to the consequences of p... more In the oil and gas industry, pipeline integrity is a serious concern due to the consequences of pipeline failure. External corrosion was identified as one of the main causes of pipeline failures worldwide. A solution that addresses the issue of detecting and quantifying corrosivity of environment for application to existing exposed pipelines has been developed. The proposed sensor consists of an electric circuit and a sensing array connected to the circuit. The sensing array is an assembly of strips made of a metal identical to that of the pipe, having the same length and width, but different thicknesses. The sensing array is exposed to the same environment as the pipe. As corrosion propagates in the metal strips of the array, it corrodes the metal until it finally breaks the metal strip apart resulting in a discontinuity in the circuit. The sensor circuit is energized using electromagnetic field, and its function is to indicate which strips in the array are fully corroded. Visual indication is provided to the operator via LEDs. The proposed sensor can be installed on existing pipelines without altering the pipe structure or disturbing the production process. It is passive and has low maintenance requirements. Circuit design was validated through lab experiments. Results obtained from experiments were consistent with simulation results.
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2016, 2016
Pipeline Inspection Gauges (PIGs) are used for internal corrosion inspection of oil pipelines eve... more Pipeline Inspection Gauges (PIGs) are used for internal corrosion inspection of oil pipelines every 3-5 years. However, between inspection intervals, rapid corrosion may occur, potentially resulting in major accidents. The motivation behind this research project was to develop a safe distributed corrosion sensor placed inside oil pipelines continuously monitoring corrosion. The intrinsically safe nature of light provided motivation for researching fiber optic sensors as a solution. The sensing fiber's cladding features polymer plastic that is chemically sensitive to hydrocarbons within crude oil mixtures. A layer of metal, used in the oil pipeline's construction, is deposited on the polymer cladding, which upon corrosion, exposes the cladding to surrounding hydrocarbons. The hydrocarbon's interaction with the cladding locally increases the cladding's refractive index in the radial direction. Light intensity of a traveling pulse is reduced due to local reduction in the modal capacity which is interrogated by Optical Time Domain Reflectometery. Backscattered light is captured in real-time while using time delay to resolve location, allowing real-time spatial monitoring of environmental internal corrosion within pipelines spanning large distances. Step index theoretical solutions were used to calculate the power loss due changes in the intensity profile. The power loss is translated into an attenuation coefficient characterizing the expected OTDR trace which was verified against similar experimental results from the literature. A laboratory scale experiment is being developed to assess the validity of the model and the practicality of the solution.
A strain based corrosion sensor for the detection of environmental corrosion of pre-stressed stru... more A strain based corrosion sensor for the detection of environmental corrosion of pre-stressed structures was developed and tested on mild steel specimens readily available. Theoretically, a beam shaped specimen under a displacement load exhibits a linear relationship between the strain observed at any point through the thickness of the beam cross-section. This property was exploited to detect thickness changes in pre-stressed mild steel specimens in a double bending configuration under an electrochemically excited corrosion reaction. The reaction was accelerated by supplying a DC current to the cell where the specimens act as anodes of the system, while graphite rods serve as cathodes. The strain was logged using fiber optic Bragg grating technology and conventional electrical strain gages simultaneously. Results show a strong relationship between the corrosion rate observed by back-calculation from supplied current and the time derivative of the measured strain values. Application of this sensor can therefore be extended to a variety of structures under mechanical loading, proving valuable for both its ability to measure corrosion rate in real-time, while maintaining an intrinsically safe nature appropriate by industrial standards.
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Papers by Oleg Shiryayev