Generally cylindrical orthotropic constitutive modeling of matrix-filled carbon nanotubes: Transverse mechanical properties and responses

Critical velocities and middle-surface displacements of anisotropic axisymmetric cylindrical shells (tubes) under a uniform internal pressure moving at a constant velocity are derived in closed-form expressions by using the Love–Kirchhoff thin shell theory incorporating the rotary inertia and material anisotropy. The formulation is based on the general three-dimensional constitutive relations for orthotropic elastic materials and provides a unified treatment of orthotropic, transversely isotropic, cubic and isotropic tubes, which can represent various composite and metallic tubes. Closed-form formulas are first obtained for the general case with both the rotary inertia and radial stress effects, which are then reduced to the special cases without the rotary inertia effect and/or radial stress effect. It is shown that when the rotary inertia effect is suppressed and the radial normal stress is neglected, the newly derived formulas for the critical velocities of orthotropic and isotropic tubes recover the two existing ones for thin tubes as special cases. An example for an isotropic tube is provided to illustrate the new formulas, which give the values of the critical velocity and dynamic amplification factor that agree well with those obtained experimentally and computationally by others.

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“…For orthotropic materials subjected to axisymmetric loading, the stress-strain relations are given by [21,41]…”

Section: Orthotropic Tubesmentioning

confidence: 99%

Critical velocities and displacements of anisotropic tubes under a moving pressure

Gao

Littlefield

2022

Mathematics and Mechanics of Solids

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“…Thakur [10] investigates the behavior of orthotropic cylinders under the combined influence of axial load and internal pressure, with a specific focus on creep deformation. Askari et al [11] introduce analytical closed-form solutions for predicting the transverse mechanical properties of matrix-filled carbon nanotubes, achieving remarkable agreement with finite element analysis results. Meanwhile, Sahni et al [12] embark on an exploration into creep analysis within a rotating cylinder, incorporating linear, quadratic volume reinforcement, and exponential factors.…”

Section: Introductionmentioning

confidence: 86%

Exploring the effective stress behavior of internally pressurized cylinders with varying density

Singh,

Gulial,

Thakur

2024

Z Angew Math Mech

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This research article presents a comprehensive examination of effective stress behavior in internally pressurized cylinders with varying density, utilizing Norton's law as the analytical framework. Our thorough numerical computations encompass a wide array of steels and steel alloys commonly employed in cylinder fabrication, covering five distinct types of anisotropy. The investigation meticulously analyzes the profound impact of anisotropy and the exponent “n” within the creep law. A key insight emerges as the effective stress values for anisotropic materials, particularly in Type‐I and Type‐II, showcase a notable reduction compared to their isotropic counterparts in Type‐III. Moreover, we highlight the active role played by an increasing density parameter in elevating the values of radial, circumferential, axial stress, and effective stress within the rotating cylinder composed of anisotropic materials.

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“…A lot of theoretical and analytical work has been performed on CNTs to predict their properties. [35][36][37][38] From theoretical studies, the tensile strength of single-walled straight CNTs is approximately 100 GPa and the young modulus can reach up to 1 TPa. 39 However, the experimental results to find the tensile strength of individual CNTs have shown some varying results with one reporting a tensile strength of 63 GPa for single-walled CNTs.…”

Section: Introductionmentioning

confidence: 99%

“…CNTs are found to have higher mechanical strength than that of iron and lower density than aluminum 34 ; hence it has a wide range of applications. A lot of theoretical and analytical work has been performed on CNTs to predict their properties 35–38 . From theoretical studies, the tensile strength of single‐walled straight CNTs is approximately 100 GPa and the young modulus can reach up to 1 TPa 39 .…”

Section: Introductionmentioning

confidence: 99%

Improvement of the tensile properties of laminated composites reinforced with Heli‐Coil forms of carbon nanotubes

Sritharan,

Askari

2023

Polymer Composites

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The traditional composite laminated structures suffer from the absence of reinforcements in the thickness direction between the laminae and microfibers, which will result in poor interaction between the laminae, individual microfiber filaments, and the resin. In addition, out‐of‐the‐plane properties are generally dominated and controlled by poor matrix properties (e.g., mechanical, electrical, and thermal). Most prior investigations were focused on the use of straight carbon nanotubes (CNTs), graphene, or nanomaterials in particle forms to improve the resin properties. Our previous research has shown that CNTs with helical (Heli‐Coil) geometries (HCNTs) are more effective as a nanoscale reinforcement to improve the properties of polymeric resins. Because of their inertness, the interfacial bonding between CNTs and the resin is generally weak, and they can be easily pulled out of the resin (inefficient load transfer) if the CNTs are in their straight forms. However, the helical geometries of HCNTs can provide unique mechanical‐interlocking mechanisms between the constituents that can substantially improve their effectiveness as a nanoscale reinforcement, leading to improvements in composite performance, properties, and multifunctionality. In this research, HCNTs at low concentrations below 0.1 wt% were processed and then used to fabricate nanocomposite laminates. Tensile test specimens were carefully prepared following the ASTM D3039/D3039M standard and then tested, analyzed, and evaluated. Additionally, the fractured test specimens were inspected and analyzed using optical and 3D scanning laser‐confocal‐microscopy imaging. The test results showed improvements of 12.3%, 11.3%, and 17.5% for the tensile strength, modulus, and strain‐to‐failure, respectively. In conclusion, traditional fiber‐reinforced composites can considerably benefit from the helical forms of HCNTs.Highlights The helical geometry of CNTs (HCNTs) is more effective for composite reinforcement. HCNTs provide unique interlocking mechanisms between the composite constituents. HCNTs can considerably improve the multifunctional characteristics of the composites. HCNTs can considerably improve the tensile properties of composite laminates. Traditional composites can substantially benefit from the helical forms of HCNTs.

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Generally cylindrical orthotropic constitutive modeling of matrix-filled carbon nanotubes: Transverse mechanical properties and responses

Cited by 5 publications

References 60 publications

Critical velocities and displacements of anisotropic tubes under a moving pressure

Critical velocities and displacements of anisotropic tubes under a moving pressure

Exploring the effective stress behavior of internally pressurized cylinders with varying density

Improvement of the tensile properties of laminated composites reinforced with Heli‐Coil forms of carbon nanotubes

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