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Tarek M. A. A. El-bagory - One of the best experts on this subject based on the ideXlab platform.
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Failure Analysis of Ring Hoop Tension Test (RHTT) Specimen Under Different Loading Conditions
Volume 3A: Design and Analysis, 2018Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Ibrahim M. AlarifiAbstract:The thermo-mechanical history during manufacturing of plastic pipes affects their resulting material mechanical behavior. Therefore, it is necessary to demonstrate a study of the mechanical behavior of ring tensile test specimens cut from pipe to obtain proper design data during evaluations of the final product from the polymeric pipe material. Ring hoop tension test (RHTT) is one of the most important methods that can be used to measure transverse tensile properties accurately for pressure pipes. Two types of tensile ring specimens are tested; single ring hoop tensile test specimen with one configuration of Dumb-bell-shaped (DBS) specimen in the transverse direction of the pipe ring specimen and double ring hoop tensile test with two configurations of DBS cut in the collinear direction from the pipe ring specimen. RHTT specimens are cut from the pipe in circumferential (transverse) directions with similar dimensions. The material of the investigated pipe is high-density polyethylene (HDPE), which is commonly used in natural Gas Piping Systems. The pipe has internal rated pressure Pi = 1.6 MPa, standard dimension ratio, SDR = 11 and external diameter, Do = 90±0.5mm. All the dimensions RHTT specimens are taken according to ASTM D 2290-12 and ASTM D 638-10 standards. The ring hoop tensile tests are conducted on specimens cut out from the pipe with thickness 9.5±0.2 mm at different crosshead speeds (VC.H = 10–1000 mm/min), and loading angle, θ equal 0° at ambient environmental temperature, Ta = 20 °C to investigate the mechanical properties of RHTT specimens. The results are compared with those obtained for DBS specimens taken along the axial pipe direction [1]. This shows the effect of DBS specimen orientation (longitudinal and circumferential) on the mechanical properties of HDPE pipe material at different crosshead speeds. The tensile testing fixture is designed specially on specified design criteria in order to test the RHTT specimen in the transverse direction. The main purpose of the design of test fixture is that it prevents the bending effect and stress concentration due to rotation of half disks during the tensile test. In order to avoid this rotation, the half disks are fixed, and their sharp ends are smoothed (rounded). The present experimental work reveals that the crosshead speeds, specimen orientation of DBS and configuration of DBS for RHTT specimens have a significant effect on the resulting mechanical behavior of HDPE pipe material.
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Evaluation of Fracture Toughness Behavior of Polyethylene Pipe Materials
Journal of Pressure Vessel Technology-transactions of The Asme, 2015Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to investigate the effect of crosshead speed, specimen thickness, and welding on the fracture toughness. The material of the investigated pipe is a high density polyethylene (HDPE), which is commonly used in natural Gas Piping Systems. The welding technique used in this study is butt-fusion (BF) welding technique. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45 mm for both welded and unwelded specimens at room temperature, Ta = 20 °C. Curved three point bend (CTPB) specimens were used to determine KQ. Furthermore, the results of fracture toughness, KQ, will be compared with the plane–strain fracture toughness, JIC, for welded and unwelded specimens. The experimental results revealed that KQ increases with increasing the crosshead speed, while KQ decreases as the specimen thickness increases. The investigation reveals that the apparent fracture toughness, KQ, for HDPE pipe of unwelded specimen is greater than that of corresponding value for welded specimen. The same trend was observed for the plane-strain fracture toughness, JIC. At lower crosshead speeds there is a minimum deviation in KQ between welded and unwelded specimens, while the deviation becomes larger with increasing crosshead speed.
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Validation of Linear Elastic Fracture Mechanics in Predicting the Fracture Toughness of Polyethylene Pipe Materials
Volume 3: Design and Analysis, 2015Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to compare between the fracture toughness based on linear elastic fracture mechanics (GIC), and that based on nonlinear fracture mechanics (JIC). The material of the investigated pipe is a high-density polyethylene (HDPE), which is commonly used in natural Gas Piping Systems. The welds at the pipe junction are produced by butt-fusion (BF), welding. Curved three-point bend (CTPB), fracture specimens are used. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45mm for both welded and unwelded specimens at room temperature Ta, equal 23°C. The study reveals that the crosshead speed has a significant effect on the fracture toughness of both welded and unwelded specimens. The results of GIC for different specimen thickness and crosshead speed found previously by the authors [1] have been compared with JIC under the same operating conditions [2]. The comparison between welded and unwelded specimens revealed that in the welded specimens there is a marginal difference between fracture toughness measured using linear elastic fracture mechanics LEFM and elastic plastic fracture mechanics EPFM, for both crosshead speeds.Copyright © 2015 by ASME
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Evaluation of Fracture Toughness Behavior of Polyethylene Pipe Materials
Volume 3: Design and Analysis, 2014Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to investigate the effect of strain rate, specimen thickness and welding on the fracture toughness. The material of the investigated pipe is a high-density polyethylene, (HDPE) which is commonly used in natural Gas Piping Systems. The welding technique used in this study is butt fusion (BF) welding technique. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45mm for both welded and unwelded specimens at room temperature, Ta equal 20 °C. Curved three point bend (CTPB) specimens were used to determine KQ. Furthermore, the results of fracture toughness, KQ, will be compared with the plane strain fracture toughness, JIC, for welded and unwelded specimens. The experimental results revealed that KQ increases with increasing the crosshead speed, while KQ decreases as the specimen thickness increases. The investigation reveals that the apparent fracture toughness, KQ, for HDPE pipe of unwelded specimen is greater than that of corresponding value for welded specimen. The same trend was observed for the plane strain fracture toughness, JIc. At lower crosshead speeds there is a minimum deviation in KQ between welded and unwelded specimens, while the deviation becomes larger with increasing crosshead speed.Copyright © 2014 by ASME
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Limit Load Determination and Material Characterization of Cracked Polyethylene Miter Pipe Bends
Journal of Pressure Vessel Technology-transactions of The Asme, 2014Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The quality of Natural Gas Piping Systems (NGPS), must be ensured against manufacturing defects. The main purpose of the present paper is to investigate the effect of loading mode and load angle (30 deg, 45 deg, and 60 deg) on the limit load of miter pipe bends (MPB), under different crack depths a/W = 0–0.4 at a crosshead speed 500 mm/min. The geometry of cracked and uncracked multi-miter pipe bends are pipe bend angle, α = 90 deg, pipe bend factor, h = 0.844, standard dimension ratio, SDR = 11, and three junctions, m = 3. The material of the investigated pipe is a high-density polyethylene (HDPE), which is commonly used in NGPS. The welds at the miter pipe junction are produced by butt-fusion welding. For all loading modes the limit load is obtained by the tangent intersection (TI) method from the load–deflection curves produced by the specially designed and constructed testing machine at the laboratory5. Tensile tests are conducted on specimens longitudinally extruded from the pipe with thickness, T = 10, 30 mm, at different crosshead speeds (5–500 mm/min), and different gauge lengths (G = 20, 25, and 50 mm) to determine the mechanical properties of welded and unwelded specimens. The fracture toughness is determined on the basis of elastic plastic fracture mechanics (EPFM). Curved three-point bend specimens (CTPB), are used. All specimens are provided with artificial precrack at the crack tip, a/W = 0.5. The effect of specimen thickness variation (B = 10, 15, 22.5, 30, 37.5, and 45 mm) for welded and unwelded specimens is studied at room temperature (Ta = 23 °C) and at different crosshead speeds, VC.H, ranging from 5 to 500 mm/min. The study reveals that increasing the crack depth leads to a decrease in the stiffness and limit load of MPB for both in-plane, and out-of-plane bending moment. In case of combined load (out-of-plane and in-plane opening; mode), higher load angles lead to an increase in the limit load. The highest limit load value occurs at a loading angle, ϕ = 60 deg. In case of combined load (out-of-plane and in-plane closing; mode), the limit load decreases with increasing load angles. At a load angle ϕ = 30 deg, the higher limit load value occurred in both cases. For combined load opening case, higher values of limit load are obtained. The crosshead speed has a significant effect on the mechanical behavior of both welded and unwelded specimens. The fracture toughness, JIC, is greater for unwelded than welded specimen.
Maher Y. A. Younan - One of the best experts on this subject based on the ideXlab platform.
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Failure Analysis of Ring Hoop Tension Test (RHTT) Specimen Under Different Loading Conditions
Volume 3A: Design and Analysis, 2018Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Ibrahim M. AlarifiAbstract:The thermo-mechanical history during manufacturing of plastic pipes affects their resulting material mechanical behavior. Therefore, it is necessary to demonstrate a study of the mechanical behavior of ring tensile test specimens cut from pipe to obtain proper design data during evaluations of the final product from the polymeric pipe material. Ring hoop tension test (RHTT) is one of the most important methods that can be used to measure transverse tensile properties accurately for pressure pipes. Two types of tensile ring specimens are tested; single ring hoop tensile test specimen with one configuration of Dumb-bell-shaped (DBS) specimen in the transverse direction of the pipe ring specimen and double ring hoop tensile test with two configurations of DBS cut in the collinear direction from the pipe ring specimen. RHTT specimens are cut from the pipe in circumferential (transverse) directions with similar dimensions. The material of the investigated pipe is high-density polyethylene (HDPE), which is commonly used in natural Gas Piping Systems. The pipe has internal rated pressure Pi = 1.6 MPa, standard dimension ratio, SDR = 11 and external diameter, Do = 90±0.5mm. All the dimensions RHTT specimens are taken according to ASTM D 2290-12 and ASTM D 638-10 standards. The ring hoop tensile tests are conducted on specimens cut out from the pipe with thickness 9.5±0.2 mm at different crosshead speeds (VC.H = 10–1000 mm/min), and loading angle, θ equal 0° at ambient environmental temperature, Ta = 20 °C to investigate the mechanical properties of RHTT specimens. The results are compared with those obtained for DBS specimens taken along the axial pipe direction [1]. This shows the effect of DBS specimen orientation (longitudinal and circumferential) on the mechanical properties of HDPE pipe material at different crosshead speeds. The tensile testing fixture is designed specially on specified design criteria in order to test the RHTT specimen in the transverse direction. The main purpose of the design of test fixture is that it prevents the bending effect and stress concentration due to rotation of half disks during the tensile test. In order to avoid this rotation, the half disks are fixed, and their sharp ends are smoothed (rounded). The present experimental work reveals that the crosshead speeds, specimen orientation of DBS and configuration of DBS for RHTT specimens have a significant effect on the resulting mechanical behavior of HDPE pipe material.
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Evaluation of Fracture Toughness Behavior of Polyethylene Pipe Materials
Journal of Pressure Vessel Technology-transactions of The Asme, 2015Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to investigate the effect of crosshead speed, specimen thickness, and welding on the fracture toughness. The material of the investigated pipe is a high density polyethylene (HDPE), which is commonly used in natural Gas Piping Systems. The welding technique used in this study is butt-fusion (BF) welding technique. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45 mm for both welded and unwelded specimens at room temperature, Ta = 20 °C. Curved three point bend (CTPB) specimens were used to determine KQ. Furthermore, the results of fracture toughness, KQ, will be compared with the plane–strain fracture toughness, JIC, for welded and unwelded specimens. The experimental results revealed that KQ increases with increasing the crosshead speed, while KQ decreases as the specimen thickness increases. The investigation reveals that the apparent fracture toughness, KQ, for HDPE pipe of unwelded specimen is greater than that of corresponding value for welded specimen. The same trend was observed for the plane-strain fracture toughness, JIC. At lower crosshead speeds there is a minimum deviation in KQ between welded and unwelded specimens, while the deviation becomes larger with increasing crosshead speed.
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Validation of Linear Elastic Fracture Mechanics in Predicting the Fracture Toughness of Polyethylene Pipe Materials
Volume 3: Design and Analysis, 2015Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to compare between the fracture toughness based on linear elastic fracture mechanics (GIC), and that based on nonlinear fracture mechanics (JIC). The material of the investigated pipe is a high-density polyethylene (HDPE), which is commonly used in natural Gas Piping Systems. The welds at the pipe junction are produced by butt-fusion (BF), welding. Curved three-point bend (CTPB), fracture specimens are used. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45mm for both welded and unwelded specimens at room temperature Ta, equal 23°C. The study reveals that the crosshead speed has a significant effect on the fracture toughness of both welded and unwelded specimens. The results of GIC for different specimen thickness and crosshead speed found previously by the authors [1] have been compared with JIC under the same operating conditions [2]. The comparison between welded and unwelded specimens revealed that in the welded specimens there is a marginal difference between fracture toughness measured using linear elastic fracture mechanics LEFM and elastic plastic fracture mechanics EPFM, for both crosshead speeds.Copyright © 2015 by ASME
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Evaluation of Fracture Toughness Behavior of Polyethylene Pipe Materials
Volume 3: Design and Analysis, 2014Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to investigate the effect of strain rate, specimen thickness and welding on the fracture toughness. The material of the investigated pipe is a high-density polyethylene, (HDPE) which is commonly used in natural Gas Piping Systems. The welding technique used in this study is butt fusion (BF) welding technique. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45mm for both welded and unwelded specimens at room temperature, Ta equal 20 °C. Curved three point bend (CTPB) specimens were used to determine KQ. Furthermore, the results of fracture toughness, KQ, will be compared with the plane strain fracture toughness, JIC, for welded and unwelded specimens. The experimental results revealed that KQ increases with increasing the crosshead speed, while KQ decreases as the specimen thickness increases. The investigation reveals that the apparent fracture toughness, KQ, for HDPE pipe of unwelded specimen is greater than that of corresponding value for welded specimen. The same trend was observed for the plane strain fracture toughness, JIc. At lower crosshead speeds there is a minimum deviation in KQ between welded and unwelded specimens, while the deviation becomes larger with increasing crosshead speed.Copyright © 2014 by ASME
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Limit Load Determination and Material Characterization of Cracked Polyethylene Miter Pipe Bends
Journal of Pressure Vessel Technology-transactions of The Asme, 2014Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The quality of Natural Gas Piping Systems (NGPS), must be ensured against manufacturing defects. The main purpose of the present paper is to investigate the effect of loading mode and load angle (30 deg, 45 deg, and 60 deg) on the limit load of miter pipe bends (MPB), under different crack depths a/W = 0–0.4 at a crosshead speed 500 mm/min. The geometry of cracked and uncracked multi-miter pipe bends are pipe bend angle, α = 90 deg, pipe bend factor, h = 0.844, standard dimension ratio, SDR = 11, and three junctions, m = 3. The material of the investigated pipe is a high-density polyethylene (HDPE), which is commonly used in NGPS. The welds at the miter pipe junction are produced by butt-fusion welding. For all loading modes the limit load is obtained by the tangent intersection (TI) method from the load–deflection curves produced by the specially designed and constructed testing machine at the laboratory5. Tensile tests are conducted on specimens longitudinally extruded from the pipe with thickness, T = 10, 30 mm, at different crosshead speeds (5–500 mm/min), and different gauge lengths (G = 20, 25, and 50 mm) to determine the mechanical properties of welded and unwelded specimens. The fracture toughness is determined on the basis of elastic plastic fracture mechanics (EPFM). Curved three-point bend specimens (CTPB), are used. All specimens are provided with artificial precrack at the crack tip, a/W = 0.5. The effect of specimen thickness variation (B = 10, 15, 22.5, 30, 37.5, and 45 mm) for welded and unwelded specimens is studied at room temperature (Ta = 23 °C) and at different crosshead speeds, VC.H, ranging from 5 to 500 mm/min. The study reveals that increasing the crack depth leads to a decrease in the stiffness and limit load of MPB for both in-plane, and out-of-plane bending moment. In case of combined load (out-of-plane and in-plane opening; mode), higher load angles lead to an increase in the limit load. The highest limit load value occurs at a loading angle, ϕ = 60 deg. In case of combined load (out-of-plane and in-plane closing; mode), the limit load decreases with increasing load angles. At a load angle ϕ = 30 deg, the higher limit load value occurred in both cases. For combined load opening case, higher values of limit load are obtained. The crosshead speed has a significant effect on the mechanical behavior of both welded and unwelded specimens. The fracture toughness, JIC, is greater for unwelded than welded specimen.
Lotfi A. Abdel-latif - One of the best experts on this subject based on the ideXlab platform.
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Limit Load Determination and Material Characterization of Cracked Polyethylene Miter Pipe Bends
Journal of Pressure Vessel Technology-transactions of The Asme, 2014Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The quality of Natural Gas Piping Systems (NGPS), must be ensured against manufacturing defects. The main purpose of the present paper is to investigate the effect of loading mode and load angle (30 deg, 45 deg, and 60 deg) on the limit load of miter pipe bends (MPB), under different crack depths a/W = 0–0.4 at a crosshead speed 500 mm/min. The geometry of cracked and uncracked multi-miter pipe bends are pipe bend angle, α = 90 deg, pipe bend factor, h = 0.844, standard dimension ratio, SDR = 11, and three junctions, m = 3. The material of the investigated pipe is a high-density polyethylene (HDPE), which is commonly used in NGPS. The welds at the miter pipe junction are produced by butt-fusion welding. For all loading modes the limit load is obtained by the tangent intersection (TI) method from the load–deflection curves produced by the specially designed and constructed testing machine at the laboratory5. Tensile tests are conducted on specimens longitudinally extruded from the pipe with thickness, T = 10, 30 mm, at different crosshead speeds (5–500 mm/min), and different gauge lengths (G = 20, 25, and 50 mm) to determine the mechanical properties of welded and unwelded specimens. The fracture toughness is determined on the basis of elastic plastic fracture mechanics (EPFM). Curved three-point bend specimens (CTPB), are used. All specimens are provided with artificial precrack at the crack tip, a/W = 0.5. The effect of specimen thickness variation (B = 10, 15, 22.5, 30, 37.5, and 45 mm) for welded and unwelded specimens is studied at room temperature (Ta = 23 °C) and at different crosshead speeds, VC.H, ranging from 5 to 500 mm/min. The study reveals that increasing the crack depth leads to a decrease in the stiffness and limit load of MPB for both in-plane, and out-of-plane bending moment. In case of combined load (out-of-plane and in-plane opening; mode), higher load angles lead to an increase in the limit load. The highest limit load value occurs at a loading angle, ϕ = 60 deg. In case of combined load (out-of-plane and in-plane closing; mode), the limit load decreases with increasing load angles. At a load angle ϕ = 30 deg, the higher limit load value occurred in both cases. For combined load opening case, higher values of limit load are obtained. The crosshead speed has a significant effect on the mechanical behavior of both welded and unwelded specimens. The fracture toughness, JIC, is greater for unwelded than welded specimen.
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Effect of Load Angle on Limit Load of Polyethylene Miter Pipe Bends
Journal of Pressure Vessel Technology-transactions of The Asme, 2014Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The aim of this paper is to investigate the effect of crack depth a/W = 0–0.4 and load angle (30 deg, 45 deg, and 60 deg) on the limit load of miter pipe bends (MPB) under out-of-plane bending moment with a crosshead speed 500 mm/min. The geometry of cracked and un-cracked multi miter pipe bends are: bend angle, α = 90 deg, pipe bend factor, h = 0.844, standard dimension ratio, SDR = 11, and three junctions, m = 3. The material of the investigated pipe is a high-density polyethylene (HDPE), which is applied in natural Gas Piping Systems. Butt-fusion welding is used to produce the welds in the miter pipe bends. An artificial crack is produced by a special cracking device. The crack is located at the crown side of the miter pipe bend, such that the crack is collinear with the direction of the applied load. The crack depth ratio, a/W = 0, 0.1, 0.2, 0.3, and 0.4 for out-of-plane bending moment “i.e., loading angle ϕ = 0 deg”. For each out-of-plane bending moment and all closing and opening load angles the limit load is obtained by the tangent intersection method (TI) from the load deflection curves produced by the specially designed and constructed testing machine at the laboratory (Mechanical Design Department, Faculty of Engineering, Mataria, Helwan University, Cairo/Egypt). For each out-of-plane bending moment case, the experimental results reveals that increasing crack depth leads to a decrease in the stiffness and limit load of MPB. In case of combined load (out-of-plane and in-plane opening; mode) higher load angles lead to an increase in the limit load. The highest limit load value appears at a loading angle equal, ϕ = 60 deg. In case of combined load (out-of-plane and in-plane closing; mode) the limit load decreases upon increasing the load angle. On the other hand, higher limit load values appear at a specific loading angle equal ϕ = 30 deg. For combined load opening case; higher values of limit load are obtained. Contrarily, lower values are obtained in the closing case.
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Plastic Load of Precracked Polyethylene Miter Pipe Bends Subjected to In-Plane Bending Moment
Journal of Pressure Vessel Technology-transactions of The Asme, 2013Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The main purpose of the present paper is to investigate the effect of crack depth on the limit load of miter pipe bends (MPB) under in-plane bending moment. The experimental work is conducted to investigate multi miter pipe bends, with a bend angle 90 o , pipe bend factor h=0.844, standard dimension ratio SDR=11,and three junctions under a crosshead speed 500 mm/min. The material of the investigated pipe is a high-density polyethylene (HDPE), which is used in natural Gas Piping Systems. The welds in the miter pipe bends are produced by butt-fusion method. The crack depth varies from intrados to extrados location according to the in-plane opening/closing bending moment respectively. For each in-plane bending moment the limit load is obtained by the tangent intersection (TI) method from the load deflection curves produced by the testing machine specially designed and constructed in the laboratory 1 . The study reveals that increasing the crack depth leads to a decrease in the stiffness and limit load of (MPB) for both inplane closing and opening bending moment. Higher values of the limit load are reached in case of opening bending moment. This behavior is true for all investigated crack depths.
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Limit Load of Pre-Cracked Polyethylene Miter Pipe Bends Subjected to In-Plane Bending Moment
ASME 2010 Pressure Vessels and Piping Conference: Volume 3, 2010Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The main purpose of the present paper is to investigate the effect of crack depth on the limit load of miter pipe bends (MPB) under in-plane bending moment. The experimental work is conducted to investigate multi miter pipe bends, with a bend angle 90°, pipe bend factor h = 0.844, standard dimension ratio SDR = 11, and three junctions under a crosshead speed 500 mm/min. The material of the investigated pipe is a high-density polyethylene (HDPE), which is used in natural Gas Piping Systems. The welds in the miter pipe bends are produced by butt-fusion method. The crack depth varies from intrados to extrados location according to the in-plane opening/closing bending moment respectively. For each in-plane bending moment the limit load is obtained by the tangent intersection (TI) method from the load deflection curves produced by the testing machine specially designed and constructed in the laboratory. The study reveals that increasing the crack depth leads to a decrease in the stiffness and limit load of (MPB) for both inplane closing and opening bending moment. Higher values of the limit load are reached in case of opening bending moment. This behavior is true for all investigated crack depths.
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Effect of Load Angle on Limit Load of Polyethylene Miter Pipe Bends
ASME 2010 Pressure Vessels and Piping Conference: Volume 3, 2010Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The aim of this paper is to investigate the effect crack depth a/W = 0 to 0.4 and load angle (30°,45°,and 60°) on the limit load of miter pipe bends (MPB) under out-of-plane bending moment with a crosshead speed 500 mm/min. The geometry of cracked and uncracked multi miter pipe bends are: bend angle, α = 90°, pipe bend factor, h = 0.844, standard dimension ratio, SDR = 11, and three junctions, m = 3. The material of the investigated pipe is a high-density polyethylene (HDPE), which is applied in natural Gas Piping Systems. Butt-fusion welding is used to produce the welds in the miter pipe bends. An artificial crack is produced by a special cracking device. The crack is located at the crown side of the miter pipe bend, such that the crack is collinear with the direction of the applied load. The crack depth ratio, a/W = 0, 0.1, 0.2, 0.3 and 0.4 for out-of-plane bending moment “i.e. loading angle φ = 0°”. For each out-of-plane bending moment and all closing and opening load angles the limit load is obtained by the tangent intersection method (TI) from the load deflection curves produced by the specially designed and constructed testing machine at the laboratory. For each out-of-plane bending moment case, the experimental results reveals that increasing crack depth leads to a decrease in the stiffness and limit load of MPB. In case of combined load (out-of-plane and in-plane opening; mode) higher load angles lead to an increase in the limit load. The highest limit load value appears at a loading angle equal, φ = 60°. In case of combined load (out-of-plane and in-plane closing; mode) the limit load decreases upon increasing the load angle. On the other hand, higher limit load values take place at a specific loading angle equal φ = 30°. For combined load opening case; higher values of limit load are obtained. Contrarily, lower values are obtained in the closing case.Copyright © 2010 by ASME
Hossam El-din M. Sallam - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Fracture Toughness Behavior of Polyethylene Pipe Materials
Journal of Pressure Vessel Technology-transactions of The Asme, 2015Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to investigate the effect of crosshead speed, specimen thickness, and welding on the fracture toughness. The material of the investigated pipe is a high density polyethylene (HDPE), which is commonly used in natural Gas Piping Systems. The welding technique used in this study is butt-fusion (BF) welding technique. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45 mm for both welded and unwelded specimens at room temperature, Ta = 20 °C. Curved three point bend (CTPB) specimens were used to determine KQ. Furthermore, the results of fracture toughness, KQ, will be compared with the plane–strain fracture toughness, JIC, for welded and unwelded specimens. The experimental results revealed that KQ increases with increasing the crosshead speed, while KQ decreases as the specimen thickness increases. The investigation reveals that the apparent fracture toughness, KQ, for HDPE pipe of unwelded specimen is greater than that of corresponding value for welded specimen. The same trend was observed for the plane-strain fracture toughness, JIC. At lower crosshead speeds there is a minimum deviation in KQ between welded and unwelded specimens, while the deviation becomes larger with increasing crosshead speed.
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Validation of Linear Elastic Fracture Mechanics in Predicting the Fracture Toughness of Polyethylene Pipe Materials
Volume 3: Design and Analysis, 2015Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to compare between the fracture toughness based on linear elastic fracture mechanics (GIC), and that based on nonlinear fracture mechanics (JIC). The material of the investigated pipe is a high-density polyethylene (HDPE), which is commonly used in natural Gas Piping Systems. The welds at the pipe junction are produced by butt-fusion (BF), welding. Curved three-point bend (CTPB), fracture specimens are used. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45mm for both welded and unwelded specimens at room temperature Ta, equal 23°C. The study reveals that the crosshead speed has a significant effect on the fracture toughness of both welded and unwelded specimens. The results of GIC for different specimen thickness and crosshead speed found previously by the authors [1] have been compared with JIC under the same operating conditions [2]. The comparison between welded and unwelded specimens revealed that in the welded specimens there is a marginal difference between fracture toughness measured using linear elastic fracture mechanics LEFM and elastic plastic fracture mechanics EPFM, for both crosshead speeds.Copyright © 2015 by ASME
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Evaluation of Fracture Toughness Behavior of Polyethylene Pipe Materials
Volume 3: Design and Analysis, 2014Co-Authors: Tarek M. A. A. El-bagory, Hossam El-din M. Sallam, Maher Y. A. YounanAbstract:The main purpose of the present paper is to investigate the effect of strain rate, specimen thickness and welding on the fracture toughness. The material of the investigated pipe is a high-density polyethylene, (HDPE) which is commonly used in natural Gas Piping Systems. The welding technique used in this study is butt fusion (BF) welding technique. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45mm for both welded and unwelded specimens at room temperature, Ta equal 20 °C. Curved three point bend (CTPB) specimens were used to determine KQ. Furthermore, the results of fracture toughness, KQ, will be compared with the plane strain fracture toughness, JIC, for welded and unwelded specimens. The experimental results revealed that KQ increases with increasing the crosshead speed, while KQ decreases as the specimen thickness increases. The investigation reveals that the apparent fracture toughness, KQ, for HDPE pipe of unwelded specimen is greater than that of corresponding value for welded specimen. The same trend was observed for the plane strain fracture toughness, JIc. At lower crosshead speeds there is a minimum deviation in KQ between welded and unwelded specimens, while the deviation becomes larger with increasing crosshead speed.Copyright © 2014 by ASME
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Limit Load Determination and Material Characterization of Cracked Polyethylene Miter Pipe Bends
Journal of Pressure Vessel Technology-transactions of The Asme, 2014Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The quality of Natural Gas Piping Systems (NGPS), must be ensured against manufacturing defects. The main purpose of the present paper is to investigate the effect of loading mode and load angle (30 deg, 45 deg, and 60 deg) on the limit load of miter pipe bends (MPB), under different crack depths a/W = 0–0.4 at a crosshead speed 500 mm/min. The geometry of cracked and uncracked multi-miter pipe bends are pipe bend angle, α = 90 deg, pipe bend factor, h = 0.844, standard dimension ratio, SDR = 11, and three junctions, m = 3. The material of the investigated pipe is a high-density polyethylene (HDPE), which is commonly used in NGPS. The welds at the miter pipe junction are produced by butt-fusion welding. For all loading modes the limit load is obtained by the tangent intersection (TI) method from the load–deflection curves produced by the specially designed and constructed testing machine at the laboratory5. Tensile tests are conducted on specimens longitudinally extruded from the pipe with thickness, T = 10, 30 mm, at different crosshead speeds (5–500 mm/min), and different gauge lengths (G = 20, 25, and 50 mm) to determine the mechanical properties of welded and unwelded specimens. The fracture toughness is determined on the basis of elastic plastic fracture mechanics (EPFM). Curved three-point bend specimens (CTPB), are used. All specimens are provided with artificial precrack at the crack tip, a/W = 0.5. The effect of specimen thickness variation (B = 10, 15, 22.5, 30, 37.5, and 45 mm) for welded and unwelded specimens is studied at room temperature (Ta = 23 °C) and at different crosshead speeds, VC.H, ranging from 5 to 500 mm/min. The study reveals that increasing the crack depth leads to a decrease in the stiffness and limit load of MPB for both in-plane, and out-of-plane bending moment. In case of combined load (out-of-plane and in-plane opening; mode), higher load angles lead to an increase in the limit load. The highest limit load value occurs at a loading angle, ϕ = 60 deg. In case of combined load (out-of-plane and in-plane closing; mode), the limit load decreases with increasing load angles. At a load angle ϕ = 30 deg, the higher limit load value occurred in both cases. For combined load opening case, higher values of limit load are obtained. The crosshead speed has a significant effect on the mechanical behavior of both welded and unwelded specimens. The fracture toughness, JIC, is greater for unwelded than welded specimen.
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Effect of Load Angle on Limit Load of Polyethylene Miter Pipe Bends
Journal of Pressure Vessel Technology-transactions of The Asme, 2014Co-Authors: Tarek M. A. A. El-bagory, Maher Y. A. Younan, Hossam El-din M. Sallam, Lotfi A. Abdel-latifAbstract:The aim of this paper is to investigate the effect of crack depth a/W = 0–0.4 and load angle (30 deg, 45 deg, and 60 deg) on the limit load of miter pipe bends (MPB) under out-of-plane bending moment with a crosshead speed 500 mm/min. The geometry of cracked and un-cracked multi miter pipe bends are: bend angle, α = 90 deg, pipe bend factor, h = 0.844, standard dimension ratio, SDR = 11, and three junctions, m = 3. The material of the investigated pipe is a high-density polyethylene (HDPE), which is applied in natural Gas Piping Systems. Butt-fusion welding is used to produce the welds in the miter pipe bends. An artificial crack is produced by a special cracking device. The crack is located at the crown side of the miter pipe bend, such that the crack is collinear with the direction of the applied load. The crack depth ratio, a/W = 0, 0.1, 0.2, 0.3, and 0.4 for out-of-plane bending moment “i.e., loading angle ϕ = 0 deg”. For each out-of-plane bending moment and all closing and opening load angles the limit load is obtained by the tangent intersection method (TI) from the load deflection curves produced by the specially designed and constructed testing machine at the laboratory (Mechanical Design Department, Faculty of Engineering, Mataria, Helwan University, Cairo/Egypt). For each out-of-plane bending moment case, the experimental results reveals that increasing crack depth leads to a decrease in the stiffness and limit load of MPB. In case of combined load (out-of-plane and in-plane opening; mode) higher load angles lead to an increase in the limit load. The highest limit load value appears at a loading angle equal, ϕ = 60 deg. In case of combined load (out-of-plane and in-plane closing; mode) the limit load decreases upon increasing the load angle. On the other hand, higher limit load values appear at a specific loading angle equal ϕ = 30 deg. For combined load opening case; higher values of limit load are obtained. Contrarily, lower values are obtained in the closing case.
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analysis of the electrofusion joining process in polyethylene Gas Piping Systems
Computers & Structures, 1997Co-Authors: M Fujikake, M Fukumura, K KitaoAbstract:Abstract Electrofusion (EF) is a semi-automated technology for joining polyethylene Gas distribution pipes. To design reliable EF joints, a computational model for the EF joining process needs to be established. In the present work, a simulation method for the EF joining process, in which the thermomechanical coupling behavior is taken into account, has been developed employing ADINA and ADINA-T. The method can be used to simulate the closure process of the clearance between the joint and the pipe. In addition, the histories of the interface pressure and the temperature distributions, the parameters which have a critical importance on the quality of the joint, can be obtained. First, the computed results were compared with the experimental data from a small scale EF joint and good agreement was obtained. Next, the method was applied to design a large scale EF joint and the design optimization was carried out, resulting in the successful development of a reliable joint.
