Multilayered Cylindrical Structures Research Articles

Tensile modulus measurement of composite materials based on distributed optical fiber strain monitoring technology

In this paper, a method was proposed to measure the elastic modulus of each layer-material in multi-layer cylindrical structures by OFDR in a large temperature range. Distributed measurement technology was used to carry out accurate measurements of strain distribution and numerical value on specimens. The accurate force-strain relationship can be obtained if the specimen is small or there is inevitable non-uniformity on the specimen. In this paper, a tensile test platform was built, and the tensile tests of optical fiber (−51.6 °C to 82.15 °C), polymer double-layer specimen (−54 °C to 63 °C), and composite three-layer specimen (−46 °C to 62 °C) were carried out. The elastic modulus of the three kinds of material and their relationships with temperature were obtained. By comparing with the standard test results, the accuracy and reliability of the test were verified.

Arbitrary target frequency cloaking for flexural waves using deep learning

Differing from electromagnetic and acoustic waves, the governing equation for elastic waves in flexural plates is not form invariant, hindering straightforward cloak design based on coordinate transformation theory. In this work, we propose a novel idea instead of the approximately equivalent transformation method, and employ scattering cancellation techniques to design a multi-layer cylindrical structure for achieving flexural wave cloaking at desired target frequencies. Moreover, we use deep learning to effectively address the time consuming issue dealing with fine-tuning design parameters for the desired response. More importantly, we adopt a method based on a tandem neural network to tackle the one-to-many mapping challenge in inverse design. It not only accurately predicts the scattering spectra of multi-layer structures in advance but also efficiently performs inverse design to obtain the required design parameters for arbitrary target frequency cloaking.

Investigation of a 2-DOF GER fluid damper in cut mode

Dampers incorporating smart materials have attracted significant interest for their application in vibration and shock isolation. Traditionally, these dampers work through shear, flow, and squeeze modes, each unique in its strengths and limitations. However, this study introduces a working mode, termed cut mode, which integrates the strengths of these existing modes. Structurally resembling the flow mode, operationally akin to the shear mode, and behaving similarly to the squeeze mode, the cut mode promises a novel approach to damping. Consequently, extensive research has been conducted at the particle level to develop a mathematical model for the cut mode, grounded in chain formation and breaking mechanisms. Thereafter, a verification prototype damper was designed to demonstrate this concept’s practicality, with the Giant Electrorheological (GER) fluid—a rheological fluid with exceptional yield strength—being employed. This damper features a multilayer cylindrical structure tailored for the cut mode, providing 2-degree of freedom (DOF) damping capabilities. This dual-DOF design is ideal for robotic arm joint applications, as it can offer damping for both axial translation and circumferential rotation simultaneously. In addition, four orifice boards were designed, fabricated, and tested to optimize and enhance the effectiveness of the cut mode further. The results are impressive, the proposed cut mode damper exhibits superior performance characteristics, indicating its great potential for engineering applications.

Partially nonlocal ring-like spatiotemporal superimposed second-order breathers under a harmonic potential

By means of reduction expression with solutions of constant-coefficient nonlinear Schrödinger system, analytical partially nonlocal ring-like spatiotemporal superimposed second-order Akhmediev and Ma breather solution is derived from the Darboux approach. In xyt or xyz coordinate, the cylindrical multilayer structure of Akhmediev and Ma breathers is embedded in the center, and rings of Akhmediev breather and plane of Ma breather extend out. Moreover, the influence of the radius and thickness parameters is studied. The Hermite parameter has impact on the layer structure of ring-like superimposed second-order breather in the z direction.

Dynamic response and vibration modes of multi-layer wound cylindrical shell for hydrogen storage under external blast loading

Multi-layer wound cylindrical shells are the preferred structures for storage vessels working in high pressure and hydrogen atmosphere. However, they are susceptible to external blast loads from accidental hydrogen explosions. In order to study the response of such structures under external blast loading, a numerical model was developed, which combined a thermo-viscoplastic constitutive model and a fluid-structure coupling approach, and was subjected to external blast loads of different TNT equivalency weights. The strain responses and initial velocity fields of the structure were analyzed. A rigid-plastic theoretical model was also developed to calculate the maximum displacement of the inner shell and was compared with the simulation results. Moreover, the axial velocity vibration histories and dominant frequencies at different locations of the steel belts were numerically obtained. In addition, four vibration modes of the steel belts were presented in this paper. Furthermore, strain growth was observed in the high-frequency vibration area, and the possible reasons for the strain growth were analyzed and discussed in detail. The results will be useful for predicting the deformation modes of such multi-layer wound cylindrical shell structures under the risk of external hydrogen explosions.

A convergence criterion for sound transmission of single-, double-, and triple-walled cylindrical shell based on Love's, Donnell's, and Flügge's shell theories

Different sound transmission loss (STL) analytical methods based on Love's, Donnell's and Flügge's cylindrical thin-shell theories have been widely used. However, there are no available convergence criterion and formulas of sound transmission losses for multi-layer cylindrical shell structures. The current convergence determination approach is to select several typical frequencies (low, middle, and high frequencies) for convergence analysis, and then estimate the convergence of all other frequencies. This typically results in sound transmission loss jumps, leading to inaccurate sound transmission loss results in the high-frequency region. In this study, a novel convergence criterion and formulas are developed for calculating sound transmission loss mode numbers in the complete convergence zones of single-, double-, and triple-walled cylindrical shells based on Love's, Donnell's, and Flügge's thin shell theories, which can be used to directly determine the truncation iterations for sound transmission losses in all frequency ranges.

Deformation and Dynamic Response of Steel Belt Staggered Multilayer Cylindrical Shell Under External Blast Loading

Abstract The deformation and dynamic response of a multilayer cylindrical shell composed of an inner shell and fourteen outer layers under external blast loads of different trinitro-toluene equivalency weights were studied. A numerical model using the thermo-viscoplastic constitutive model and considering fluid–structure coupling between explosion wave and structure was developed. The displacement in axial direction and cross section, as well as the effective strain responses, were analyzed to demonstrate the potential deformation of the shell structure. Results demonstrate that different materials cause inconsistent displacement and separation to develop in the inner and outer shells. In order to address the problem that the displacement of the inner shell is hard to measure due to the shielding and covering of the outer shell, a theoretical formula for calculating the maximum displacement of the inner shell was developed. The deflection process and stress triaxiality histories of the inner shell were investigated, and the results showed that compressive stress is the primary cause of plastic deformation. Additionally, the delamination that appeared in the outer shell was discussed, and it was revealed that there are two factors of delamination: (1) Stress waves spread across adjacent layers in the opposite direction because steel belts were wound in the opposite direction between the two adjacent layers; (2) Outer layers experienced uneven compressive loads. The results will be helpful to provide a reference for the intrinsic safety design of such multilayer cylindrical structures for hydrogen storage, etc.

Localized manipulation of spoof surface acoustic skyrmions with deep-subwavelength gradient structures

Skyrmions with stable vector field configurations have produced various derivatives with various topological textures, such as the Néel type, Bloch type, anti-type, and higher-order Néel type. Here, we theoretically and experimentally demonstrate that the vector field configuration of Néel-type skyrmionic modes can be locally manipulated using gradient grooves in a deep-subwavelength three-dimensional multilayer cylindrical structure. We experimentally observe that the skyrmionic modes can be contracted or expanded to manipulate the distribution of the velocity vectors by tuning the groove depth gradient along the structural radius, which is robust against structural deformations and defects. This type of controllable acoustic skyrmion provides new dimensions for advanced sound information processing, transportation, and data storage in compact structures.

Generalized differential quadrature element solution, swarm, and GA optimization technique to obtain the optimum frequency of the laminated rotary nanostructure

Optimization of the fiber angle in the laminated composite material to achieve the highest strength or stability has great importance in structural design. In the present study, we aim to utilize genetic algorithm (GA) and particle swarm optimization (PSO) together to find the best angle of composite layers in a multilayer cylindrical shell structure. To this aim, a detailed formulation of the composite cylindrical structure is presented using nonlocal strain gradient theory (NSGT), zigzag theory, and Hamilton's principle for a shear deformable shell displacement field. The modal equations of motion are further solved using the general differential quadrature element method (GDQEM). Having the route of obtaining the resonance frequency of the cylindrical composite structure, GA-PSO is engaged to obtain the optimal angle of the laminate composite to achieve the highest frequency. It is revealed that angle θ = 37.5° provides the highest frequency for a single-layer cylindrical shell. Using this angle, stacking sequences for 3, 5, and 7 layers’ composite are optimized to have the highest frequency. In the end, a detailed parametric study is presented using optimum condition shell composite. The results show that after 30 composite layers, changing the number of layers seems to be not effective on the resonance frequency of the cylinder for both simply supported and clamped boundary conditions.

Fast and Numerically Stable Analytical Computations for the Power Induced in Cylindrical Multilayered Conductors Under External Magnetic Fields

Despite the spectacular development of numerical methods, the use of analytical formulas to solve electromagnetism problems in multilayered complex structures still remains attractive due to their much shorter computation time. One of the most essential computations is a calculation on the proximity effects observed in a wire that is immersed in an external harmonic electromagnetic field. The mathematical model of this problem is known and contains Bessel functions, which are numerically unstable for very low and high arguments. In this article, a novel numerically stable algorithm for the computation of proximity effects and power induced in a multilayered cylindrical structure is presented.

Extended Method of Lines to Model Cylindrical Graphene-Based Multilayer Structures

In this article, the method of lines (MoL) is extended to analyze 2-D multilayer structures loaded with graphene plates in cylindrical coordinates. Accordingly, the admittance transformation matrices through a 2-D interface are derived taking into account the tensor-form conductivity of the magnetized graphene plate. The transformations determine the admittance matrices on all the planes of the multilayer structure. Furthermore, a technique to obtain the characteristic equation and hence the propagation constant of the structure is proposed by matching the fields at the interfaces loaded with graphene. As a result, the proposed method is able to analyze a generic graphene-loaded multilayer structure in cylindrical coordinates. As a proof of concept, the MoL is exploited to analyze 2-D cylindrical graphene microstrip and stripline transmission lines. The proposed method is validated by comparing the results with COMSOL simulations exhibiting a good agreement. Tuning the chemical potential of the graphene plate has potential applications in tunable microwave attenuators and phase shifters.

Superscattering of Underwater Sound via Deep Learning Approach

We design a multilayer cylindrical structure to realize superscattering of underwater sound. Because of the near degeneracy of resonances in multiple channels of the structure, the scattering contributions from these resonances can overlap to break the single-channel limit of subwavelength objects. However, tuning the design parameters to achieve the target response is an optimization process that is tedious and time-consuming. Here, we demonstrate that a well-trained tandem neural network can deal with this problem efficiently, which can not only forwardly predict the scattering spectra of the multilayer structure with high precision, but also inversely design the required structural parameters efficiently.

Superscattering of underwater sound via deep learning approach

Abstract We design a multilayer cylindrical structure to realize superscattering of underwater sound. Because of the near degeneracy of resonances in multiple channels of the structure, the scattering contributions from these resonances can overlap to break the single-channel limit of subwavelength objects. However, tuning the design parameters to achieve the target response is an optimization process which is tedious and time-consuming. Here, we demonstrate that a well-trained tandem neural network can deal with this problem efficiently, which can not only forwardly predict the scattering spectra of the multilayer structure with high precision, but also inversely design the required structural parameters efficiently.

Experimental evaluation of fire hazard of lithium-ion battery during its mechanical damage

Purpose. To experimentally determine the combustion temperature of a lithium-ion battery (LIB) due to mechanical damage to its case by a sharp object. At the same time, to determine the cooling-down time of the lithium-ion battery after combustion and the further mathematical description of this process. Methodology. To achieve the set goal, a laboratory bench with the appropriate measuring equipment was prepared. For mathematical modelling of the cooling process, experimental values and methods for studying heat transfer processes in solid multilayer cylindrical structures were applied. Findings. Experimental studies showed that the maximum temperature on the lithium-ion battery case reached 715 C. In turn, the average values showed a temperature of 665 . The average cooling time to a temperature of 50 C was at least 17 minutes. Mass loss studies showed that after combustion are complete, all elements lose about 53% of their original mass. Originality. The combustion temperature and cooling-down time of Panasonic NCR18650B (LiNi0.8Co0.15Al0.05O2) LIB specifically have been determined for the first time. In parallel with experimental studies, mathematical modelling of the cooling process of the LIB was carried out using the theory of heat transfer. It was found that the results of the mathematical modelling correlate well with the experimental values. This approach allows, in the future, carrying out analytical studies on LIB without the need (where possible) to conduct experiments. Practical value. Further implementation and application of the obtained mathematical model will make it possible to determine the cooling time, the possibility of heating other (adjacent) LIB to a critical temperature, the possibility of ignition from overload, various LIB using only geometric parameters without the need for experimental research. Determining the cooling time of the LIB after combustion is a valuable indicator since it allows one to practically estimate the time during the LIB remains a potential source of danger.

Construction and performance analysis of a solar thermophotovoltaic system targeting on the efficient utilization of AM0 space solar radiation

Solar thermophotovoltaic (STPV) has great potential as efficient power supply source for spacecraft to meet the demand of spacecraft miniaturization. In this work, a novel space STPV system is proposed to achieve the efficient utilization of the AM0 space solar radiation. Metamaterial structures were designed and FDTD method is used to analyze their radiation regulation mechanism. A multi-layer cylindrical periodic structure is used as the absorber which realizes a total absorptance of 0.9283 to AM0 radiation. A cylindrical periodic structure is used as the emitter to reshape the broadband thermal radiation as narrowband to match with the Si/InGaAsSb tandem cell, which realizes a highest TPV efficiency of 51.36%. System performance analysis is conducted and the system presents a highest STPV efficiency of 40.86% and good adaptability under wide range of operating parameters, which reveals its great potential to realize the efficient utilization of AM0 solar radiation for space power supply.

Multilayer acoustic invisibility cloak based on composite lattice

A concentric cylindrical cloak is showed here to achieve the acoustic cloaking phenomenon. The introduced structure consists of MNE layers and water in MNE substrate in the MHz frequency range. Due to avoiding the incoming acoustic waves by the shell, the object can be hidden inside the cylindrical area of any shape. In order to improve the quality of cloaking, we have optimized the desired shell by considering the manufacturing technology. We show that an optimized, acoustic cloak based on composite lattice structure can reduce the scattering of an object more than a 20-layer realization of acoustic cloak based on multilayer cylindrical structure. This design approach can substantially simplify the fabrication of cloaking shells. In this research, to study the acoustic distribution of the desired structure, finite element method (FEM) has been used to analyze the structure in two dimensions and a cloak of natural materials with isotropic properties has been designed using effective medium theory.

Response characteristics of drill-string guided wave in downhole acoustic telemetry

Modeling of a drill-string acoustic channel has been an important topic in downhole telemetry for a long time. The propagation of drill-string guided waves in the borehole contains excitation, attenuation, and mode conversion issues that have not been considered by existing modeling methods. In this article, we formulate a hybrid modeling method to investigate the response characteristics of a fundamental-mode drill-string wave in various borehole environments. This hybrid method provides channel functions, including transmitting and receiving deployments, periodicity of the structure, and formation property changes. The essential physics of the drill-string wave propagation is captured with a one-dimensional model. The analytical solutions of the wavefield in multilayered cylindrical structures are introduced into a propagation matrix to express drill-string-wave interactions with the borehole environments. The effectiveness of the proposed method is confirmed through comparison with the finite-difference method. In addition, by designing numerical models, we investigate the conversion effect of the drill-string wave at the tool joint. We demonstrate that the conversion intensity of the drill-string wave is positively correlated not only with the cross-sectional area of the tool joint but also with the wave impedance of the outer formation. Hard formation outside the borehole reduces the energy leakage while intensifying the conversion of drill-string waves to Stoneley waves, and the opposite is true for the drill string in an infinite fluid. The converted Stoneley waves interfere with the drill-string waves, resulting in variations of bandgap distribution, which challenges the reliability of the data transmission.

Transmission and absorption spectra of light waves on graphene-embedded Cylindrical Photonic Quasicrystals

We present a study for the transmission and absorption spectra of light propagating radially in multilayered cylindrical structures where there are concentric layers of dielectric materials with graphene sheets interposed between the layers. The aims are to explore the role of quasiperiodicity in these so-called Cylindrical Photonic Quasicrystals as well as how this property can be modified due to the presence of conducting graphene sheets. Specifically, we employ TiO2 and SiO2 as the two components of the multilayers, and an analysis of the optical properties is made for four distinct aperiodic arrangements of the layers: Fibonacci, Thue–Morse, Double–Period, and Octonacci. The calculations involve solving Maxwell's equations within the layers, subject to modified boundary conditions due to the graphene interfaces. Then a transfer matrix formalism is utilized to deduce the transmission and absorption spectra, which are highly structured and fragmented (with the appearance of frequency bands and gaps) because of the quasiperiodicity. The numerical examples illustrate the influence on the spectra of varying the doping of the graphene sheets. In all generations of the four sequences, it is found that the transmission spectra for the transverse-electric and transverse-magnetic waves tend to develop an increase of asymmetry with respect to frequency variations when the graphene doping is increased.

Thermo-mechanical analysis of a multilayer hollow cylindrical thermal protection structure with functionally graded ultrahigh-temperature ceramic to be heat resistant layer

In this study, a multilayer thermal protection system (TPS) of hollow cylindrical structure for hypersonic flight vehicles (HFVs) is modeled and its thermo-mechanical responses are investigated. The multilayer structure has an ultrahigh-temperature ceramic (UHTC) or a functionally graded ultrahigh-temperature ceramic (FG-UHTC) outer layer for heat resistance, a SiC aerogel middle layer for thermal insulation, and a TC4 inner layer for load bearing. Temperature dependent material properties as well as time dependent boundary conditions are considered. Governing equations of the temperature and displacement fields are carried out and thermo-mechanical responses of the structure, especially of the heat resistance outer layer, are calculated by the differential quadrature method (DQM) and Newmark method. Influences of component volume fraction, porosity, gradient distribution and the thickness of FG-UHTC layer on the thermo-mechanical responses are discussed by numerical examples. The main aim of this paper is to introduce the design and mechanical analysis methods of FG materials into heat resistant composites for TPSs, as well as to propose an effective numerical process to solve the complete nonlinear governing equations.

Application of low field magnetic resonance for defect detection in multi-layered cylindrical composite structures

ABSTRACT Polymer-based Glass composite cylindrical structures consisting of multi-layered configuration for special applications were tested with low magnetic field nuclear magnetic resonance (NMR) technique. Relaxation times of chemical species at the interface of adhesive bond were investigated. Studies indicated that the single-sided NMR inspection of such composite structures is a feasible non-destructive evaluation technique to study the adhesive bond interface properties. Results of single-sided inspection over cylindrical surface using low field NMR having magnetic field strength of 0.3 T (12.88 MHz RF frequency) indicated distinct signal intensity values for different constituent materials. Interfacial defects such as de-bond and voids were detectable through the multi-layers of the structure. Overlapping defects at multiple interfaces have no bearing on the signal as well as relaxation times of constituent materials.