The control of elastic waves in metamaterials has predominantly focused on beam and plate structures, with relatively limited research on cylindrical shell structures. However, cylindrical shell structures are used in various applications where elastic wave modulation plays a crucial role in vibration noise control and vibration energy research. Consequently, this paper achieves frequency conversion of elastic waves in cylindrical shell structures using piezoelectric metamaterials. The study demonstrates that elastic wave frequency conversion can be accomplished through a “single-sensor-dual-actuator” approach, conventional physical law of frequency is not variable can be break by frequency conversion. This work begins with theoretical derivation of the kinetic equation for cylindrical shell structures, along with design of piezoelectric metamaterial cylindrical shells and the development of time-dependent transfer functions. Then, elastic waves frequency conversion is thoroughly analyzed by simulation on axial and circumferential cylindrical shells, these analysis results are investigated and discussed. Finally, frequency conversion function is verified through experiments which are collecting elastic wave parameters in frequency domain. The experimental results align closely with the simulation outcomes, demonstrating that frequency conversion of incident elastic waves can be successfully achieved in the range of 7 kHz to 9 kHz. Moreover, frequency conversion with different values can be realized by modifying key parameters in the transfer function. This work provides a solid experimental foundation and methodology for achieving elastic waves frequency conversion in curved shell structure, contributing to the broader understanding and application of elastic wave metamaterials.
Shell-Beam micromechanical models to improve the efficiency of simulations of composites under longitudinal compression
D. Bikos, F. Poh, R.S. Trask, P. Robinson, S. Pimenta
doi:10.1016/j.compstruct.2024.118830
采用壳梁细观力学模型提高复合材料纵向压缩模拟效率
The variability of fibre paths in composite microstructures is a key parameter influencing their compressive behaviour; however, despite numerous developments, no micromechanical finite element simulation has represented enough fibres to be statistically representative of this variability. This paper proposes and develops a methodology which replaces the computationally-expensive continuum 3D finite elements with shells and beams (SB) to simulate explicitly the matrix and the fibres in real microstructures of composites under longitudinal compression. The SB methodology is illustrated in simulations using fibre paths from micro-computed tomography of real microstructures. The SB methodology shows a reduction in simulation time over 99.9% compared to the conventional continuum approach; the accuracy of the compressive strength and kinking direction predicted by the SB methodology were at least 94% and 97% respectively (compared to the continuum approach). This new proposed micromechanical simulation methodology can advance the state of the art by efficiently capturing the effect of microstructural imperfections on the performance of composites under longitudinal compression.
Enhanced sound absorption properties of a semi-open underwater periodic acoustic metamaterial
Zihan Feng, Xiaoliang Xu, Shurui Wen, Zhijing Wu, Fengming Li
doi:10.1016/j.compstruct.2024.118831
半开放式水下周期性声学超材料的增强吸声性能
In order to enhance the underwater low-frequency sound absorption performance, a semi-open underwater periodic acoustic metamaterial (SUPAM) is proposed combining the slit and the rubber shear deformation mechanisms of the acoustic energy dissipation. According to the slit absorber theory and the complex viscosity model of viscoelastic material, the theoretical model for predicting the sound absorption performance of the SUPAM is established using the transfer matrix method, the correctness of which is validated by the well agreement of its result with that of the finite element method and experiment, respectively. The influence of the sound incidence angle, slit width, air cavity height and rubber thickness on the sound absorption property of the SUPAM is discussed. It is found that the introduction of the slit enables acoustic waves to effectively enter the SUPAM and increases the amount of sound energy dissipated by the shear deformation of the rubber damping layer. A sound absorption coefficient above 0.8 can be achieved almost across an ultra-wide frequency range of 176–5000 Hz for the SUPAM composed of metacells based on the stepped design, which shows its extraordinary low-frequency sound absorption performance.
Composites Part A: Applied Science and Manufacturing
Protection concept for foamed radar-absorbing sandwich composites with high-conductive film against lightning strike impacts
Woo-Hyeok Jang, Dongjun Hong, Shanigaram Mallesh, Juhyeong Lee, Chanyeop Park, Chun-Gon Kim, Won-Ho Choi, Youngwoo Nam
doi:10.1016/j.compositesa.2024.108660
具有高导电性薄膜的泡沫雷达吸收夹层复合材料对雷击冲击的防护概念
This paper presents a foamed radar-absorbing sandwich composite using Ni-plated glass fiber, serving as a dielectric loss material and a high-conductive film for lightning strike protection (LSP). Image processing found that surface damage area was reduced by 38.7 % in high-conductive films compared to those without. Furthermore, micro-X-ray CT revealed no critical damage, such as fiber breakage, deeper than the film. Moreover, specimens without high-conductive film experienced a 37.8 % decrease in −10 dB bandwidth after the lightning strike (LS) test, while high-conductive film specimens maintained a −10 dB bandwidth. The proposed structure offers high radar-absorbing performance, effectively protecting the structure from lightning.
BiVO4/MoO3 composites for ultra high performance energy-storing photocathodic protective coatings
Siyi Li, Bin Liu, Huayang Tian, Yujie Ning, Shuo Wu, Yihan Song, Qi Wang
doi:10.1016/j.compositesa.2024.108691
用于超高性能储能光电阴极保护涂层的BiVO4/MoO3复合材料
The practical application of photocathodic protection (PCP) technology has been hindered by its failure in darkness. In this work, The BiVO4/MoO3 composites were synthesized through a simple hydrothermal method, which were used as functional fillers, and then added to polyurethane resins to prepare energy-storing PCP coatings. This achievement enabled efficient PCP even in darkness. The 304 stainless steel coated with PCP coating (PB10M1) exhibited excellent photoelectrochemical properties as photocurrent density of 394 μA/cm2, and the corrosion potential decreased by about 350 mV. Furthermore, the cathodic protection effect of PB10M1 could last for 15 h in the dark, showing exceptional stability, superior energy-storage ability and potential application. The superior PCP performance of BiVO4/MoO3 should be attributed to the cooperative effect in heterojunction structure and electronic regulation revealed by electrochemical characterizations and DFT calculation.
Structure and performance evolutions with temperature, stress, and thermal-force coupling of the silica aerogel composite for suppressing thermal runaway propagation of LIBs
Ming Liu, Yong Kong, Jin Tang, Bangqin Zhang, Xiaodong Shen
doi:10.1016/j.compositesa.2024.108692
抑制lib热失控传播的二氧化硅气凝胶复合材料的结构和性能随温度、应力和热力耦合的演变
Silica aerogel composite (SAC) with high thermal stability up to 1200 °C for suppressing thermal runaway (TR) propagation of Li-ion batteries (LIBs) was developed via a facile base-catalyzed single-step sol–gel-impregnation process. Structure and thermal performance evolutions of the silica aerogel composite with temperature, stress, and thermal-force coupling condition were investigated firstly. Thermal conductivity of the SAC with SiC as opacifier (SAC-SiC) is 0.021–0.045 W/(m·K) at 600–1200 °C, which are lower than those of its state-of-art counterparts at 600–1200 °C or even lower temperatures. The structure and thermal insulation performance of the SAC-SiC are hardly affected by stress (0.01–0.9 MPa) under thermal-force coupling conditions. The use of SAC with a thickness of 2.35 mm suppressed the TR propagation of a commercial cell (NCM 811) in a module successfully. The resulting SAC is exceptional in thermal insulation under high temperature and thermal-force coupling conditions.
A semipermanently stable, photocrosslinkable graphene colloid: A fresh strategy for fabricating polymer nanocomposites
Seung Koo Park, Bong Je Park, Won Bae Cho, Eun Jin Shin, Suntak Park, Hyung Cheol Shin
doi:10.1016/j.compositesa.2024.108693
半永久稳定、可光交联的石墨烯胶体:制造聚合物纳米复合材料的新策略
It is challenging to choose a polymer matrix suitable for preparing a homogenous graphene/polymer nanocomposite due to their incompatibility. This study introduces a highly stable, photocrosslinkable graphene colloid prepared by calculating the three-dimensional (3D) distance (Δδ¯) of solubility parameters for the polymer nanocomposites with well-distributed graphene. Δδ¯between tetra(ethylene glycol)diacrylate (TEGDA) and graphene was calculated to be low, 4.29. The black ink-like graphene colloid solutions in TEGDA were formulated and stable for nearly one year. After UV irradiation, the colloid layers could be converted to transparent, robust, and thermostable polymer composite films with several tens-nano-sized graphene. Without light scattering loss, the transparency of the films with ca. 50 µm thickness showed 92 ∼ 47 % depending on the graphene content. They exhibited nonlinear optical properties. A conversion of reverse saturable into saturable absorption was unexpectedly observed in relatively high graphene concentrations. We proved that the colloids are fit for preparing graphene-well-dispersed polymer nanocomposites.
High-performance automotive adhesives with urethane-modified and nanophase-separated epoxy systems
Kyeng-Bo Sim, Jong-Ho Back, Gi-Yeon Han, Hyun-Joong Kim
doi:10.1016/j.compositesa.2024.108652
高性能汽车胶粘剂与聚氨酯改性和纳米相分离环氧系统
Epoxy resins are extensively used across various industries due to their exceptional adhesive strength, mechanical properties, and chemical resistance. However, their inherent brittleness, low crack resistance, and limited elongation and fracture toughness restrict their standalone applications. Although numerous toughening strategies have been explored, challenges such as increased viscosity, difficulties in achieving uniform dispersion, opacity, and limited improvement in elongation remain unresolved. To address these limitations, aliphatic diols with urethane linkages were synthesized with varying diamine chain lengths (230, 400) and used as additives in epoxy systems, resulting in the formation of nano-sized domains that promote phase separation. This phase-separated structure facilitated uniform stress distribution and enhanced energy absorption, leading to an elongation of 11.5 % at 50 % A-D230. A-D400 formed larger domains, exhibiting superior performance under high impact, with an Izod impact strength of 72 J/m. Furthermore, aliphatic-modified epoxy synthesized through the thermal reaction of aliphatic diol with epichlorohydrin, when used as a reactant, acted as a flexible segment in the epoxy matrix, enhancing stress absorption and toughness. This approach also demonstrated improved thermal stability and shear strength. The toughening strategies utilizing additives and reactants in epoxy can be tailored to meet the specific performance requirements, such as adhesive strength, impact resistance, durability, and fatigue life, making these epoxy systems highly applicable for automotive adhesive formulations.
Finite element simulation of novel Polybenzoxazine-Carbon fibre composites prior to Low Earth Orbit: A comparative analysis of mechanical properties
H.Lucas Lu, Kyungil Kong, George Worden, Joseph F. Gargiuli, James Thomas, Katharine Robson Brown, Ian Hamerton
doi:10.1016/j.compositesa.2024.108670
近地轨道前新型聚苯并恶嗪-碳纤维复合材料的有限元模拟:力学性能对比分析
High-fidelity finite element (FE) models have been applied to simulate the mechanical properties of carbon fibre-reinforced polymer composites, which include a novel polybenzoxazine matrix resin designed for space applications. FE analysis was used to construct a digital model that replicates the geometry of the plain-woven fabric composite structure, employing X-ray computed tomography data to detail the quality of the composite laminate (manufactured with a thickness of 3.00 mm and fibre volume fraction of 53.0 %). The simulation results are in agreement with experimental data: the simulated tensile modulus (69.2 GPa) closely matches the experimental result (68.8 GPa), and this comparative analysis is also agreeable for the tensile strength (493 MPa simulated, 485 MPa experimental), flexural modulus (48.8 GPa simulated, 48.7 GPa experimental), flexural strength (554 MPa simulated, 526 MPa experimental), compressive modulus (4.20 GPa simulated, 4.00 GPa experimental), and compressive strength (328 MPa simulated, 335 MPa experimental).
Fabrication, progress and future perspective of MXene/polymeric nano composites for electromagnetic shielding application – A review
Mayank Pandey, C. Anju, B.V.S. Praveen, Ali Dashan, Raj Kumar Verma, Bahram Ramezanzadeh
doi:10.1016/j.compositesa.2024.108682
电磁屏蔽用MXene/聚合物纳米复合材料的制备、研究进展及展望
MXene is the fastest-growing 2D material with remarkable qualities including surface tunability, high conductivity, easy processibility, thermal stability, and water dispersibility. MXene also represents effective electromagnetic interference (EMI) shielding properties, which can be further enhanced by adopting it with other materials such as polymers, carbon derivatives, fibers, and metal–organic frameworks (MOF). MXene/polymer nanocomposites harness the advantageous traits of both MXenes and polymers, combining the inherent strength of MXenes with the flexibility and ease of processing of polymers. These composite materials exhibit remarkable attributes, including exceptional electromagnetic interference shielding and impressive charge storage capabilities, surpassing those of alternative nanocomposites. This comprehensive review examines the fundamental theory and mechanism of EMI shielding followed by various fabrication processes of MXene-based Polymeric nanocomposites. This paper summarizes the current state of the art, as well as the potential future developments, in the manufacturing of MXene materials for electromagnetic interference (EMI) shielding.
Simulation of thermal degradation in a composite material using phase field method
M. Abdoussalam, A. Nait-Ali, B. Batiot, M. Calvat, D. Halm
doi:10.1016/j.compscitech.2024.111015
用相场法模拟复合材料的热降解
Carbon fibers/epoxy resin composite laminates decompose by pyrolysis when submitted to high heat fluxes under inert atmosphere. A rigorous thermodynamic approach with internal variables has been adopted to better capture the phenomenon under study. In the literature, the models used to describe this degradation generally do not take into account the influence of microstructural heterogeneity on the decomposition rate, on the degradation kinetics and, consequently, on the propagation of the thermal front decomposition. To consider the variability of the composite microstructure, simulations at the microscale were conducted, involving a strong coupling between the evolution of the thermal degradation rate (which follows an Arrhenius law) and the temperature evolution using the phase-field method. An experimental approach with cone calorimeter has been undertaken to achieve two major objectives: first, to calibrate model parameters, and then to compare the numerical results with experimental data for the purpose of model validation. This comparison will focus on the analysis of degradation kinetics as well as the evolution of mass loss.