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Papers by Neda Fazlalipour
Advances in transdisciplinary engineering, Dec 6, 2023
Advances in transdisciplinary engineering, Dec 6, 2023
International Journal of Pressure Vessels and Piping
Lecture notes in civil engineering, 2023
Structural applications of composite materials are used in various structures of the oil and gas ... more Structural applications of composite materials are used in various structures of the oil and gas industry, water supply and sewage systems and a wide range of industries, such as marine, aerospace, and military industries. This paper aims to numerically investigate the influence of local dent caused by an indenter on the buckling behaviour of glass fabric-reinforced polymer cylindrical shells when subjected to external pressure. For this purpose, 24 finite element numerical models with five layers and a stacking sequence [30/-30/30/-30/30] were simulated in ABAQUS. The effect of dent depth (2, 4, 6 and 8 mm) and orientation (0 and 90 degrees) that was created at the mid-height, the 1/3rd and the 2/3rd of the shell height on the buckling behaviour of the composite cylindrical shells were evaluated. The results underscored that whilst the location of the local dent and the depth affected the shells' buckling capacity, the dent's orientation had minimal effect on the buckling capacity of the cylindrical shells.
Advances in Structural Engineering
A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid s... more A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid steel cylinders and one circular cross-section tube equipped with slotted holes, is proposed for seismic resilience of structures. In the proposed damper, a system of bolts was used to connect up various components of the damper, allowing inspection and replacement of the damaged components without any requirement for the replacement of the entire damper. Nonlinear finite element analyses using ABAQUS were carried out to verify the experimental results and to investigate the effect of damper geometric properties on the yield load capacity of the C-TTD dampers. The seismic performance characteristics of 4-storey, 8-storey, and 15-storey steel structures equipped with C-TTD dampers were determined by nonlinear time history analyses using three different earthquake excitations. The results indicated that when the structures were equipped with C-TTD dampers, the inter storey drift decreased i...
Advances in Structural Engineering
A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid s... more A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid steel cylinders and one circular cross-section tube equipped with slotted holes, is proposed for seismic resilience of structures. In the proposed damper, a system of bolts was used to connect up various components of the damper, allowing inspection and replacement of the damaged components without any requirement for the replacement of the entire damper. Nonlinear finite element analyses using ABAQUS were carried out to verify the experimental results and to investigate the effect of damper geometric properties on the yield load capacity of the C-TTD dampers. The seismic performance characteristics of 4-storey, 8-storey, and 15-storey steel structures equipped with C-TTD dampers were determined by nonlinear time history analyses using three different earthquake excitations. The results indicated that when the structures were equipped with C-TTD dampers, the inter storey drift decreased i...
Journal of Constructional Steel Research
This research elaborates the interactive response of thin steel cylindrical shells under axial an... more This research elaborates the interactive response of thin steel cylindrical shells under axial and uniform peripheral pressure. The method of the research was mainly experimental, which was evaluated against theoretical analyses of other studies and design standards. The geometric variable was applied as thickness variation in a stepwise manner whilst designing the specimens; this is seen in cylindrical shells employed as storage structures such as silos. The axial loading was applied as a constant pre-loading to all specimens, which followed by applying uniform pressure that increased until the initial buckling, global buckling (hereafter called buckling in this paper), and collapse of the specimens were observed. The results underscored the significance of the slenderness on the capacity of the shells with varying thicknesses. For shells with lower slenderness values of the bottom strake(s), a more stable post-buckling response was identified. These specimens experienced somewhat symmetric formation of the buckling lobes compared to the specimens with a single strake. The capacity rise was also evaluated against the mass gain, and for some specimens, an insignificant mass gain led to a remarkable capacity gain.
Journal of Constructional Steel Research, 2022
This research elaborates the interactive response of thin steel cylindrical shells under axial an... more This research elaborates the interactive response of thin steel cylindrical shells under axial and uniform peripheral pressure. The method of the research was mainly experimental, which was evaluated against theoretical analyses of other studies and design standards. The geometric variable was applied as thickness variation in a stepwise manner whilst designing the specimens; this is seen in cylindrical shells employed as storage structures such as silos. The axial loading was applied as a constant pre-loading to all specimens, which followed by applying uniform pressure that increased until the initial buckling, global buckling (hereafter called buckling in this paper), and collapse of the specimens were observed.
The results underscored the significance of the slenderness on the capacity of the shells with varying thicknesses. For shells with lower slenderness values of the bottom strake(s), a more stable post-buckling response was identified. These specimens experienced somewhat symmetric formation of the buckling lobes compared to the specimens with a single strake. The capacity rise was also evaluated against the mass gain, and for some specimens, an insignificant mass gain led to a remarkable capacity gain.
Thin-Walled Structures
Abstract An experimental study was conducted to investigate the buckling behaviour of cylindrical... more Abstract An experimental study was conducted to investigate the buckling behaviour of cylindrical shells with a stepwise wall thickness when subjected to a combination of axial compression preloading and external pressure. A significant reduction was observed in the buckling load and the post-buckling capacity of the cylindrical shells with increasing the value of axial compression preloading. The existing analytical models for predicting the buckling load of the cylindrical shells were modified for cylindrical shells with stepwise wall thickness. A numerical model was developed and verified using the experimental results, and interaction graphs for the axial compression and external pressure were derived.
Cylindrical shell, Tank, Stepwise wall thickness, Buckling, Combined loading. An experimental, nu... more Cylindrical shell, Tank, Stepwise wall thickness, Buckling, Combined loading. An experimental, numerical, and theoretical study was conducted to investigate the buckling behaviour of cylindrical shells with stepwise wall thickness when subjected to a combination of axial compression preloading and external pressure. The effect of axial precompression on the buckling load, buckling mode of the cylindrical shell were evaluated. Additionally, numerical modelling was employed to verify the experimental results and relationships available in the design codes for predicting the buckling load of cylindrical shells with a uniform wall thickness were modified to for cylindrical shells with stepwise wall thickness. Comparable predictions between the modified analytical and numerical models and the experiment were observed.
Advances in transdisciplinary engineering, Dec 6, 2023
Advances in transdisciplinary engineering, Dec 6, 2023
International Journal of Pressure Vessels and Piping
Lecture notes in civil engineering, 2023
Structural applications of composite materials are used in various structures of the oil and gas ... more Structural applications of composite materials are used in various structures of the oil and gas industry, water supply and sewage systems and a wide range of industries, such as marine, aerospace, and military industries. This paper aims to numerically investigate the influence of local dent caused by an indenter on the buckling behaviour of glass fabric-reinforced polymer cylindrical shells when subjected to external pressure. For this purpose, 24 finite element numerical models with five layers and a stacking sequence [30/-30/30/-30/30] were simulated in ABAQUS. The effect of dent depth (2, 4, 6 and 8 mm) and orientation (0 and 90 degrees) that was created at the mid-height, the 1/3rd and the 2/3rd of the shell height on the buckling behaviour of the composite cylindrical shells were evaluated. The results underscored that whilst the location of the local dent and the depth affected the shells' buckling capacity, the dent's orientation had minimal effect on the buckling capacity of the cylindrical shells.
Advances in Structural Engineering
A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid s... more A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid steel cylinders and one circular cross-section tube equipped with slotted holes, is proposed for seismic resilience of structures. In the proposed damper, a system of bolts was used to connect up various components of the damper, allowing inspection and replacement of the damaged components without any requirement for the replacement of the entire damper. Nonlinear finite element analyses using ABAQUS were carried out to verify the experimental results and to investigate the effect of damper geometric properties on the yield load capacity of the C-TTD dampers. The seismic performance characteristics of 4-storey, 8-storey, and 15-storey steel structures equipped with C-TTD dampers were determined by nonlinear time history analyses using three different earthquake excitations. The results indicated that when the structures were equipped with C-TTD dampers, the inter storey drift decreased i...
Advances in Structural Engineering
A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid s... more A new brace-type slit damper, called ‘Circular Tube-in-Tube Damper (C-TTD), comprises two solid steel cylinders and one circular cross-section tube equipped with slotted holes, is proposed for seismic resilience of structures. In the proposed damper, a system of bolts was used to connect up various components of the damper, allowing inspection and replacement of the damaged components without any requirement for the replacement of the entire damper. Nonlinear finite element analyses using ABAQUS were carried out to verify the experimental results and to investigate the effect of damper geometric properties on the yield load capacity of the C-TTD dampers. The seismic performance characteristics of 4-storey, 8-storey, and 15-storey steel structures equipped with C-TTD dampers were determined by nonlinear time history analyses using three different earthquake excitations. The results indicated that when the structures were equipped with C-TTD dampers, the inter storey drift decreased i...
Journal of Constructional Steel Research
This research elaborates the interactive response of thin steel cylindrical shells under axial an... more This research elaborates the interactive response of thin steel cylindrical shells under axial and uniform peripheral pressure. The method of the research was mainly experimental, which was evaluated against theoretical analyses of other studies and design standards. The geometric variable was applied as thickness variation in a stepwise manner whilst designing the specimens; this is seen in cylindrical shells employed as storage structures such as silos. The axial loading was applied as a constant pre-loading to all specimens, which followed by applying uniform pressure that increased until the initial buckling, global buckling (hereafter called buckling in this paper), and collapse of the specimens were observed. The results underscored the significance of the slenderness on the capacity of the shells with varying thicknesses. For shells with lower slenderness values of the bottom strake(s), a more stable post-buckling response was identified. These specimens experienced somewhat symmetric formation of the buckling lobes compared to the specimens with a single strake. The capacity rise was also evaluated against the mass gain, and for some specimens, an insignificant mass gain led to a remarkable capacity gain.
Journal of Constructional Steel Research, 2022
This research elaborates the interactive response of thin steel cylindrical shells under axial an... more This research elaborates the interactive response of thin steel cylindrical shells under axial and uniform peripheral pressure. The method of the research was mainly experimental, which was evaluated against theoretical analyses of other studies and design standards. The geometric variable was applied as thickness variation in a stepwise manner whilst designing the specimens; this is seen in cylindrical shells employed as storage structures such as silos. The axial loading was applied as a constant pre-loading to all specimens, which followed by applying uniform pressure that increased until the initial buckling, global buckling (hereafter called buckling in this paper), and collapse of the specimens were observed.
The results underscored the significance of the slenderness on the capacity of the shells with varying thicknesses. For shells with lower slenderness values of the bottom strake(s), a more stable post-buckling response was identified. These specimens experienced somewhat symmetric formation of the buckling lobes compared to the specimens with a single strake. The capacity rise was also evaluated against the mass gain, and for some specimens, an insignificant mass gain led to a remarkable capacity gain.
Thin-Walled Structures
Abstract An experimental study was conducted to investigate the buckling behaviour of cylindrical... more Abstract An experimental study was conducted to investigate the buckling behaviour of cylindrical shells with a stepwise wall thickness when subjected to a combination of axial compression preloading and external pressure. A significant reduction was observed in the buckling load and the post-buckling capacity of the cylindrical shells with increasing the value of axial compression preloading. The existing analytical models for predicting the buckling load of the cylindrical shells were modified for cylindrical shells with stepwise wall thickness. A numerical model was developed and verified using the experimental results, and interaction graphs for the axial compression and external pressure were derived.
Cylindrical shell, Tank, Stepwise wall thickness, Buckling, Combined loading. An experimental, nu... more Cylindrical shell, Tank, Stepwise wall thickness, Buckling, Combined loading. An experimental, numerical, and theoretical study was conducted to investigate the buckling behaviour of cylindrical shells with stepwise wall thickness when subjected to a combination of axial compression preloading and external pressure. The effect of axial precompression on the buckling load, buckling mode of the cylindrical shell were evaluated. Additionally, numerical modelling was employed to verify the experimental results and relationships available in the design codes for predicting the buckling load of cylindrical shells with a uniform wall thickness were modified to for cylindrical shells with stepwise wall thickness. Comparable predictions between the modified analytical and numerical models and the experiment were observed.