Multilayered Cylinder Research Articles

The spectral methods for the propagation of thermoelastic waves in multilayer cylinders based on nonlocal strain gradient elasticity

The spectral methods for the propagation of thermoelastic waves in multilayer cylinders based on nonlocal strain gradient elasticity

Investigation on the electro-magneto-thermoviscoelastic response of multilayer rotating hollow cylinder based on two-temperature theory and fractional-order viscoelastic systems

Hollow cylinder structures play a crucial role in scientific experiment and industrial production, and are widely used in various fields, including pipeline transportation of gases and liquids, high-speed engines, porous combustors, and other engineering equipments. As a result, they have garnered considerable academic interest over the years. However, as science and technology progress, studying hollow cylinders under a single physical field is no longer sufficient for real-world applications. Additionally, the classical viscoelastic model has become inadequate in accurately describing complex materials with properties that fall between elasticity and viscosity. Therefore, this article investigates the electro-magneto-thermoviscoelastic coupling behavior of an infinitely long rotating multilayer homogeneous hollow cylindrical conductor. In this study, based on the fractional-order three-phase lag thermoelasticity theory, the fractional-order viscoelastic system and the two-temperature theory are introduced to further increase the accuracy of the model. To solve the corresponding equations, the Laplace transform technique is employed, resulting in solutions with dimensionless physical quantities. Graphs and tables are used to make relevant comparisons and assess the effects of time, material layering properties, different thermoelastic theoretical models, fractional-order parameters and angular velocity on the considered physical quantities. Finally, the numerical results are discussed to reveal the dynamic response of a homogeneous multilayered hollow cylinder under the complex coupling of multiple physical fields.

A study on the small failure probabilities of cylindrical composite hydrogen storage tanks using subset simulation

Although composite hydrogen tanks are becoming increasingly intriguing, a detailed structural reliability analysis is still lacking. The current landscape of analysis for pressurised multilayer cylinders, while rich in research, lacks tools to deal with the low probabilities of failure that govern the design of hydrogen tanks. This study presents a computational framework integrating the Subset Simulation method (SS) for assessing the failure probability of composite tanks used for hydrogen storage. To explore how randomness impacts design parameters, this study utilises a limit state equation derived from the thin-walled circumferential model of composite pressure tanks. Five random variables, each with varying coefficients of variation (COVs), are incorporated into the analysis. For comparison and validation purposes, two methods Monte Carlo simulations and FORM have been used. The analysis revealed that SS excels at estimating the low failure probabilities of composite hydrogen tanks, and showed also the feasibility and accuracy of SS in the prediction of burst pressure since good agreement was obtained between the probabilistic approach and the experimental results. Furthermore, the uncertainties related to internal pressure and composite thickness affect significantly the reliability of the structure and can lead to the shrinkage of the safety margin and the failure of the vessel.

Enlargement of the localized resonant band gap by using multi-layer structures

Multi-layer structures possess highly geometrically tunable optical resonances to change the surface plasmon frequencies in the wide range. A simple analytic model is presented to describe the plasmon hybridization of multi-layer metamaterial structures with multipole resonances. We theoretically demonstrate that the number of plasmon modes increases with the number of layers, which results in the enlargement of the localized resonant optical band gap. To explore the interaction between incident fields and multi-layer structures, we derive the closed-form perturbed field in terms of a generalized polarization matrix, whose dimension matches the number of layers. This enables us to obtain the eigenmode frequencies and their corresponding eigenfunctions for three-dimensional multi-layer concentric spheres and two-dimensional multi-layer concentric cylinders in a vacuum setting. These findings offer nanoscientists a general design principle that can be applied to facilitate the proper selection of the metamaterial parameters, thereby inducing the desired resonance and enabling customized applications to be realized.

Modified nonlocal couple stress problem of magneto thermoelasticity in a multilayered cylinder with hall current, higher order time derivatives and two phase lags

Modified nonlocal couple stress problem of magneto thermoelasticity in a multilayered cylinder with hall current, higher order time derivatives and two phase lags

Nonlocal Couple Stress Vibration of Pasted Thermo Elastic Multilayered Cylinder with Hall Current and Multi Dual Phase Lags

Nonlocal Couple Stress Vibration of Pasted Thermo Elastic Multilayered Cylinder with Hall Current and Multi Dual Phase Lags

A simple method for mechanical analysis of pressurized functionally graded material thick-walled cylinder

The complex function method is employed to establish a mechanical model for pressurized thick-wall cylinders made of functionally graded materials (FGM). This model is applicable to all radial varying modes of material properties, including both continuous and discontinuous variations in Young’s modulus and Poisson’s ratio. The main concept behind this mechanical model involves dividing the thick-walled cylinder into concentric thin cylinders, each equipped with a pair of analytical functions representing stress functions. By imposing continuity conditions between adjacent thin cylinders and considering the stress boundary conditions of the entire structure, all unknown forms of analytical functions can be determined. Subsequently, by establishing the correspondence relationship between these analytical functions and stress or displacement, it becomes possible to solve for the stress or displacement at any radial position within the thick-walled cylinder. Through comparison and verification against the numerical simulation results, it can demonstrate that as long as the differential scale is sufficiently small, high accuracy can be achieved in the final result. In other words, solutions obtained for multi-layered hollow cylinder converge toward those obtained for continuously graded thick-walled cylinder. Notably, by starting from the level of stress function and avoiding complex differential and integral equations, a linear equation system can provide information on stress and displacement distributions along the radial direction. Therefore, compared to other solving methods available, this proposed approach offers simplicity and applicability.

Superscattering of electromagnetic waves from subwavelength dielectric structures

Superscattering, corresponding to the scattering cross section of a scatterer being significantly larger than its single-channel limit, has attracted increasing attention due to its huge potential for practical applications. The realization of superscattering relies on the overlapping of multiple resonance modes in a scatterer. Accordingly, superscattering phenomena have been observed primarily in alternating plasmonic/dielectric layered structures which support surface plasmons. However, such systems suffer from high Ohmic loss due to the excitation of surface plasmons, hindering broader application of the plasmonic/dielectric hybrid systems. On the other hand, subwavelength structures based on high permittivity dielectric materials (such as ferroelectric ceramics) offer expansive opportunities to realize electric and magnetic resonances at microwave and THz frequencies. Here, based on optimization methods involving mode analysis, we numerically demonstrate superscattering from individual multilayered dielectric cylinders. The maximum scattering cross section achieved is determined by the collective contributions from several resonance modes excited in a complex cylinder. Our results reveal that a combination of mode analysis and a custom optimization method can enable efficient designs of complex dielectric structures exhibiting exotic scattering responses.

Thermoelastic response of multilayer cylinders: The direct integration and single-solid approach

An approach for solving the plane nonaxisymmetric thermoelasticity problems in multilayer cylinders is suggested from the single-solid standpoint, which implies considering a multilayer structure as a single unity with a step-wise variation of material properties. The direct integration method was used to the advantage of our approach by applying toward the compatibility equation in terms of strains instead of the one in terms of stresses. As a result, the governing equation is derived without involving generalized derivatives by the radial coordinate and then reduced to an integral equation of the second kind. Using the resolvent-kernel for solving the latter equation, the thermal stresses are computed as the Fourier series whose constituents are explicitly determined by the corresponding constituents of the thermal loading.

Advance optimum design of multi-layer compound cylinders

The purpose of this work is to find the optimum design for two-layer compound cylinders of the same material with an open end condition by using the elimination method. The optimization method depends on reducing the number of design variables with a simultaneous yield hypothesis for all layers of the compound cylinder. A combination of von Mises and Tresca criteria is used as a yield criterion, and the superposition principle is used to evaluate the equivalent stresses for each cylinder. By considering the working pressure and the internal diameter of the inner cylinder as the design parameters (constants during optimization) and the total thickness of the compound cylinder as the objective function, the optimization algorithm has been programmed in C# with a user-friendly graphical interface. The optimization results (outer diameter, interference diameter, and shrinkage pressure) are obtained for different working pressures and compared with the optimum design, which is based only on the Tresca criterion. The total mass of the compound cylinder can be reduced by up to 50% by using the von Mises–Tresca combination criterion. The optimized results are validated numerically by using finite element analysis in the ANSYS Workbench. The theoretical result and the FEA result agree with each other with errors of about 2%. The behavior of the optimized parameters for different working pressures is also observed and presented.

A fast convergent solution of wave propagation for multilayer inhomogeneous cylindrical dielectric waveguides using a semianalytical method

Abstract This paper presents an accurate and efficient semianalytical method based on the Galerkin procedure for solving electromagnetic wave propagation problems in multilayer inhomogeneous cylindrical dielectric waveguides. The method represents the field in each inhomogeneous layer by a linear combination of eigenfunctions with unknown coefficients, which are expressed using the inner products of a series of basis functions, following the Galerkin procedure. The continuity of the field and its radial derivative is enforced at the interface between adjacent layers. By applying this procedure to all inhomogeneous layers, the Helmholtz equations are transformed into linear algebraic equations with expanded coefficients in matrix form, allowing the complicated wave propagation problem in a multilayer inhomogeneous waveguide to be solved as a matrix eigenvalue problem. The method is validated by providing detailed propagation characteristics for various multilayer inhomogeneous cylinders with different permittivity profiles. The accuracy and efficiency of the proposed method are demonstrated through comparisons with results obtained using other numerical techniques.

Steady-state thermodynamic process in multilayered heterogeneous cylinder

Steady-state thermodynamic process in multilayered heterogeneous cylinder

Mode-Based Superdirective Optimization Strategy for Multi-layered Dielectric Cylinder

Mode-Based Superdirective Optimization Strategy for Multi-layered Dielectric Cylinder

Coupled modeling circulating multi-layer wellbore temperature and stress field during deepwater high-temperature and high-pressure gas well testing

During the testing of offshore high-temperature and high-pressure (HTHP) gas wells, the heat transferred by the high temperature gas flowing through the tubing frequently leads to the rupture of the wellhead cement sheath, which can directly result in the failure of the wellhead seal and pose a significant safety hazard. In this study, an advanced multi-layer temperature and stress coupling model is introduced, which combines wellbore heat transfer and the multi-layer thick-walled cylinder theory. Subsequently, commercial software and measured data are utilized to verify the validity of the coupling model. The simulation results show that the average error between the model and the commercial software is 0.84%, and the average error between the model and the measured data is 1.65%. There is the optimal gas production in testing process by calculating the temperature and stress distribution during the test of the South China Sea HTHP gas well, and the stress distribution sensitivity of the multi-layer model is analyzed. The sensitive parameters are ranked in descending order of importance as follows: the number of cement sheath layers, gas-oil ratio (GOR), performance parameters of the cement sheath, performance parameters of the formation, and casing wall thickness. Furthermore, in the three-layer model, the circumferential stress at the first interface of the cement sheath is lower compared to the two-layer model. The findings provide a theoretical reference for comprehending the distribution of wellbore temperature and stress during testing, which is crucial for accurately assessing wellbore safety and ensuring optimal operational conditions.

Analysis of Multilayer Cylindrical Thermal Conduction With a Time-Varying Convective Boundary Condition

Abstract Heat transfer in a multilayer body plays a key role in design and optimization of several engineering systems. While the analysis of simple multilayer problems is quite straightforward, realistic scenarios such as time-dependent boundary conditions result in significant complications in analysis. This work presents thermal analysis of a one-dimensional heat-generating multilayer cylinder with time-varying convective heat transfer at the boundary. Such a scenario may occur in applications such as nuclear reactors, jet impingement cooling, turbine blade heat transfer, as well as casting and related manufacturing processes. Analysis is presented for both annular and solid cylinders. A derivation for the temperature distribution is carried out, using a shifting function to split the time-dependent boundary condition into two parts, followed by appropriate mathematical substitution. For particular special cases, the analytical results derived here are shown to reduce exactly to results from past work. Good agreement of the theoretical results with numerical simulations is also demonstrated. Thermal response to various realistic time-dependent boundary conditions is analyzed. This work contributes towards the design of realistic multilayer problems and may facilitate the optimization of engineering systems where multilayer thermal conduction plays a key role.

Selection of Design Scheme for an Ultrahigh-Pressure Hydrostatic Extrusion Cylinder

In this study, the mechanical models of a multilayer combined extrusion cylinder and a steel-wire-winding extrusion cylinder were established and compared using a finite element simulation and existing experimental cases. This work provides theoretical support for the selection of an ultrahigh-pressure extrusion cylinder. Comparative analysis of an ultrahigh-pressure extrusion structure was carried out. The mathematical optimization model is established based on the mechanical model, and the ultimate bearing capacities of the schemes are compared. Additionally, the winding mode and the number of core layers of the extrusion cylinder are compared and analyzed, which provides a theoretical basis for the parameter design of the steel-wire-winding ultrahigh-pressure extrusion cylinder. This work holds good theoretical significance and practical value for the promotion and application of ultrahigh-pressure hydrostatic extrusion technology.

Analytical behavior and bearing capacity research on out-of-code tapered CFDST members under pure torsion and compression-torsion combination

Facing the apparent enhancement of rated power of offshore wind turbines, the increasing rotor diameter and blade length gradually pose severe challenges to its support structure for resisting extreme loads. Due to the remarkable composite effect, the recently developed tapered concrete-filled double skin steel tubular (CFDST) members can provide a high-performance structural type and competitive application prospect compared to traditional steel tower barrels. Therefore, this paper conducted the numerical and theoretical research on out-of-code tapered CFDST members under pure torsion and compression-torsion combination. The finite element (FE) model was established to examine the full-range mechanism including torque versus deformation response (T-θ curve), interaction behavior and component contribution, indicating that four characteristic points can distinguish the T-θ curve under pure torsion, and slight contact pressure between the inner tube and sandwich concrete exists along the height direction. The parametric study was performed to investigate the influences of geometric-physical parameters, e.g., by increasing tapered angle (ψ) 0.2°, the torsional capacity obtains a reduction of 5%; hollow ratios (χ), axial compression ratios, and diameter-to-thickness (D/t) ratios of double-skin tubes obviously affect the torsion resistance; altering steel yield grade influences torsional capacity than concrete grade. Subsequently, a theoretical multilayered cylinder model as the simplified design tool was proposed to simulate full-range T-θ curves of tapered CFDST members. Moreover, a modified design method for calculating N-T correlation curve was developed and validated by introducing the refined equations of pure torsion resistance (Tu), where the design methods in current codes displayed a quite conservative prediction for tapered CFDST members with out-of-code parameters (e.g., hollow ratios or D/t ratios). The above research on out-of-code tapered CFDST members can offer valuable design guidelines for its engineering applications.

Single scattering and effective medium description of multilayer cylinder metamaterials: Application to graphene- and to metasurface-coated cylinders

Single scattering and effective medium description of multilayer cylinder metamaterials: Application to graphene- and to metasurface-coated cylinders

Study on Band Gap Characteristics of Phononic Crystal Double-Layer Beam Structure Attached by Multilayer Cylinder

Intended for the vibration and noise control problems faced by many engineering fields, a fresh variety of phononic crystal beam structure was constructed by attaching a one-dimensional periodic multilayer cylinder to a double-layer beam structure. Utilizing the finite element method and the Bloch theorem, the vibration modes of the band structure, the critical point of the band gap and the associated finite structure’s vibration transmission is estimated, and then the band gap characteristics of the structure are comprehensively studied. The results show that reasonable parameter design can achieve vibration and noise control in a certain frequency range. Based on the modal analysis, the mechanism of band gap opening is revealed. By comparing the single-layer beam and double-layer beam with the same parameters, the advantages of the double-layer beam in vibration reduction and noise reduction are shown. The study’s findings offer a fresh concept for ship engineering disciplines including vibration and noise reduction technology.

A Semianalytical Method for Electromagnetic Scattering by Infinitely Long Arbitrary Shaped Multilayer Cylinders at Oblique Incidence

A simple and fast method for determining the field scattered from an infinite, arbitrary-shaped multilayer cylinder that is obliquely illuminated by a TMz plane wave is presented. The proposed method is a generalization of the meshless method that was previously introduced for the normal incidence case. The main structure of the procedure is similar to the one given for the normal incidence case. However, in the oblique incidence case, the problem cannot be handled as a scalar problem by considering only one field component, namely, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E_{\text {z}}$ </tex-math></inline-formula> for a TMz plane wave. Accordingly, all components of both the electric and magnetic field vectors are involved in the procedure and at each layer, and they are expressed as series of cylindrical functions with unknown coefficients. These coefficients are determined through the solution of a linear system of equations, which is constructed by first enforcing the continuity of the tangential components of the electric and magnetic field vectors on each boundary between the layers, then expressing the cylindrical functions in these continuity relations as Fourier series, and using the orthogonality of complex exponentials. After determining the coefficients, all field components at any point can be easily computed through the series representations.