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【新文速递】2023年11月6日复合材料SCI期刊最新文章

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今日更新:Composite Structures 12 篇,Composites Part A: Applied Science and Manufacturing 1 篇

Composite Structures

Torsional mechanical properties and damage mechanism of glass fiber-ramie hybrid circular tube

Ke Jun, Liu Li-jie, Wu Zhen-yu, Le Zhong-ping, Bao Luo, Luo Dong-wei

doi:10.1016/j.compstruct.2023.117680

玻璃纤维-拉米混合圆管的扭转力学性能和损伤机理

Compared with other green natural fibers, ramie has higher mechanical properties and lower cost. In this study, ramie and glass fiber are made into composite circular tubes by two-dimensional braiding, and their torsional mechanical properties and damage mechanisms are investigated. The results show that under the unit wall thickness, compared with the pure glass fiber circular tube, the maximum torsion angle of the hybrid circular tube with ramie and glass fiber spindle ratio of 1:3 increases by 78%, the weight is reduced by 22%, the cost is reduced by 14%, the maximum torque is increased by 10% and the torsional stiffness is reduced by 18.75%. When the loading direction is the same as the implantation direction with more glass fiber content, the failure is caused by buckling. When the loading direction is the same as the implantation direction with more ramie content, the failure is caused by matrix fracture or fiber fracture. The numerical simulation results of the damage model are consistent with the experimental data and the damage morphology, which verifies the effectiveness of the finite element model. These conclusions provide a reference for the engineering application of composite circular tubes with environmental protection, lightweight and anti-torsion failure ability.

与其他绿色天然纤维相比,苎麻具有更高的机械性能和更低的成本。本研究将苎麻和玻璃纤维通过二维编织制成复合圆管,并对其扭转力学性能和损伤机理进行了研究。结果表明,在单位壁厚条件下,与纯玻璃纤维圆管相比,苎麻与玻璃纤维主轴比为 1:3 的混合圆管的最大扭转角增加了 78%,重量减轻了 22%,成本降低了 14%,最大扭矩增加了 10%,扭转刚度降低了 18.75%。当加载方向与玻璃纤维含量较多的植入方向相同时,破坏是由屈曲引起的。当加载方向与植入方向相同且苎麻含量较多时,破坏是由基体断裂或纤维断裂引起的。损伤模型的数值模拟结果与实验数据和损伤形态一致,验证了有限元模型的有效性。这些结论为具有环保、轻质和抗扭转破坏能力的复合材料圆管的工程应用提供了参考。


Free vibration characteristics of integrated fluted-core composite sandwich cylinders

Li Xinyu, Zhang Hao, Yang Haiyang, Luo Junrong, Xiao Zhongmin, Lei Hongshuai

doi:10.1016/j.compstruct.2023.117691

 

集成凹槽夹芯复合材料圆柱体的自由振动特性

Due to their excellent mechanical properties and inherent design versatility, fluted-core composite sandwich structures have gained substantial attention in aerospace and rail transit applications. This study investigated the free-vibration characteristics of composite fluted-core sandwich cylinders. Theoretical models were established following the Rayleigh-Ritz method to predict the natural frequencies of sandwich cylinders under free vibration. The representative cylindrical specimens were prepared using carbon fiber-reinforced plastics (CFRP) and integrated forming co-cured method. To analyze the additional effects of cutouts on vibration performance, specimens with circular cutouts were also fabricated. The vibration tests were performed to determine the natural frequencies and modal shapes under free-free boundary conditions. Validated finite element simulations were employed to assess the accuracy of theoretical results and investigate the influences of geometric parameters on the structural vibration behavior. The results indicated that circumferential lobar modes characterized the first five mode shapes. Significant enhancements were attained by increasing the structural stiffness through adjustments in the circumferential cell number, core-ribs thickness, or size of cutouts. However, when the structural stiffness increases beyond a certain threshold, it has limited effect on the vibration frequencies. The findings provided a comprehensive understanding of the vibration characteristics and optimized design of fluted-core sandwich cylinders.

由于具有优异的机械性能和固有的设计多功能性,凹槽芯复合材料夹层结构在航空航天和轨道交通应用中得到了广泛关注。本研究调查了复合材料凹槽夹芯圆柱体的自由振动特性。采用雷利-里兹法建立了理论模型,以预测夹层圆柱体在自由振动下的固有频率。使用碳纤维增强塑料(CFRP)和集成成型共固化方法制备了具有代表性的圆柱形试样。为了分析切口对振动性能的额外影响,还制作了带有圆形切口的试样。振动测试用于确定自由边界条件下的固有频率和模态振型。为了评估理论结果的准确性,并研究几何参数对结构振动行为的影响,采用了经过验证的有限元模拟。结果表明,圆周叶状模态是前五种模态振型的特征。通过调整圆周单元数、芯肋厚度或切口尺寸来增加结构刚度,可以显著提高振动性能。然而,当结构刚度增加超过一定临界值时,对振动频率的影响有限。研究结果为凹槽夹芯圆柱体的振动特性和优化设计提供了全面的理解。


Optimal thickness distribution design for blending composite laminates using buckling factor prediction

Huynh Thanh N., Lee Jaehong

doi:10.1016/j.compstruct.2023.117693

利用屈曲因子预测混合复合材料层压板的最佳厚度分布设计

This article introduces a two-stage optimization approach for finding optimal blended composite laminate designs where the optimal thickness distribution is predicted based on determined stacking sequences. At each iteration, the stacking sequences are first optimized and then utilized as inputs to predict the optimal regional thicknesses through CNN-based regional buckling factor prediction. By predicting the optimal thicknesses, the proposed process simplifies the highly constrained mixed-variable blending optimization problem, expands its option space, and reduces the number of design variables, all of which improve the combinatorial optimization efficiency. An integration of the proposed approach with a design guideline-based Genetic Algorithm is presented. The approach is applied to solve an 18-panel benchmark blending problem, the acquired solutions are compared with those of previous studies in the literature. The obtained result highlights the significant enhancement in performance of the integrated method.

本文介绍了一种用于寻找最佳混合复合材料层压板设计的两阶段优化方法,根据确定的堆叠顺序预测最佳厚度分布。在每次迭代中,首先优化堆叠序列,然后将其作为输入,通过基于 CNN 的区域屈曲因子预测来预测最佳区域厚度。通过预测最佳厚度,所提出的流程简化了高度受限的混合变量混合优化问题,扩大了其选项空间,并减少了设计变量的数量,所有这些都提高了组合优化效率。本文介绍了建议方法与基于设计准则的遗传算法的整合。该方法被应用于解决一个 18 面板基准混合问题,所获得的解决方案与之前文献中的研究进行了比较。结果表明,集成方法的性能显著提高。


Strength and manufacturability enhancement of a composite automotive component via an integrated finite element / artificial neural network multi-objective optimization approach

Henrique Fonseca João, Jang Woojung, Han Dosuck, Kim Naksoo, Lee Hyungyil

doi:10.1016/j.compstruct.2023.117694

通过综合有限元/人工神经网络多目标优化方法提高汽车复合材料部件的强度和可制造性

This study addresses the enhancement of an injection-molded fiber-reinforced plastic / metal hybrid automotive structure and its plastic injection molding process through the integration of the finite element method, artificial intelligence and evolutionary search methods. Experiments are conducted to validate the finite element models. The orthogonal array and Latin hypercube methods are employed to generate a database via finite element analysis. The database is then used to train artificial neural networks that accurately evaluate component distortion, manufacturing time, and structural strength. A genetic optimization algorithm is applied to identify optimal process parameters. The procedure was demonstrated to simultaneously reduce product warpage and manufacturing time by 10 and 62 %, respectively, when compared with the reference manufacturing process while strength is kept above the required levels with a reduced number of required data points. A more in-depth investigation into the causes of strength variation and deformation is also provided. The results contribute to the advance of robust composite automotive structures with superior quality, manufactured through efficient processes.

本研究通过整合有限元方法、人工智能和进化搜索方法,对注塑成型的纤维增强塑料/金属混合汽车结构及其注塑成型工艺进行改进。实验验证了有限元模型。采用正交阵列法和拉丁超立方法通过有限元分析生成数据库。然后利用该数据库训练人工神经网络,以准确评估部件变形、制造时间和结构强度。遗传优化算法用于确定最佳工艺参数。结果表明,与参考制造流程相比,该流程可同时将产品翘曲和制造时间分别减少 10% 和 62%,同时在减少所需数据点数量的情况下将强度保持在所需水平之上。此外,还对强度变化和变形的原因进行了更深入的研究。这些结果有助于推动通过高效工艺制造出质量上乘的坚固复合材料汽车结构。


Formation of non-uniform fibre distribution and its effect on the flexural performance of pultruded GFRP box beams

Qi Songming, Alajarmeh Omar, Alhawamdeh Mohammad, Shelley Tristan, Schubel Peter, Rendle-Short Kendric, Zeng Xuesen

doi:10.1016/j.compstruct.2023.117695

 

非均匀纤维分布的形成及其对拉挤 GFRP 箱形梁弯曲性能的影响

This study investigates the effect of non-uniform fibre distribution (NUFD) as a defect in the pull-winding manufacturing process on the mechanical properties of pultruded glass fibre-reinforced polymer (GFRP) box section profiles. These profiles exhibit balanced mechanical properties but are susceptible to NUFD during production, negatively affecting local buckling capacity. Experimental and numerical analyses were conducted on pultruded GFRP profiles manufactured under three winding tension configurations, resulting in a 5% variance in load capacity during bending. Results show that corner NUFD influences local buckling capacity more than flange NUFD. Specifically, corner NUFD decreases load capacity by up to 20%, while flange NUFD increases it by up to 3%. Conversely, the effect of NUFD location is insignificant to the failure determined by the material strength without buckling instability. Moreover, a linear relationship between the rotational restraint coefficient and corner fibre volume fraction provides insight into the impact of material imperfections on load capacity.

本研究调查了非均匀纤维分布(NUFD)这一拉卷制造过程中的缺陷对拉挤玻璃纤维增强聚合物(GFRP)箱型材机械性能的影响。这些型材具有均衡的机械性能,但在生产过程中容易出现 NUFD,对局部屈曲能力产生负面影响。我们对在三种缠绕张力配置下生产的拉挤 GFRP 型材进行了实验和数值分析,结果显示弯曲时的负载能力差异为 5%。结果表明,转角 NUFD 比凸缘 NUFD 对局部屈曲能力的影响更大。具体来说,角部无损探伤最多会降低 20% 的承载能力,而凸缘无损探伤最多会提高 3%。相反,NUFD 位置的影响对于由材料强度决定的无屈曲不稳定性的失效并不明显。此外,旋转约束系数与边角纤维体积分数之间的线性关系有助于深入了解材料缺陷对承载能力的影响。


Manufacturing and characterization of an interpenetrating metal matrix composite reinforced with a 3D-printed metallic glass lattice structure (Ni60Nb20Ta20)

Dittmann Kerstin, Trauth Anna, André Weidenmann Kay

doi:10.1016/j.compstruct.2023.117697

用 3D 打印金属玻璃晶格结构(Ni60Nb20Ta20)增强的互穿金属基复合材料的制造与表征

Metallic glasses (MG) exhibit remarkable properties, like high strength, hardness, and elastic strain limit due their amorphous structure. But they also exhibit low ductility and brittle behavior, making them less suitable for monolithic components. Therefore, MG offer high potential for use as a reinforcing phase in a ductile matrix. Especially interpenetrating metal matrix composites (MMCs) are suitable, since good interfacial adhesion can be achieved due to the metallic character of the MG and mechanical properties can be further enhanced by the interpenetrating structure. Temperature during manufacturing process must be below crystallization temperature of the MG. Until now, interpenetrating MMCs have been manufactured by infiltrating the metal matrix foam with MG, requiring a high melting temperature of the matrix and thus excludes lightweight metals. In this work it was possible to infiltrate an open porous lattice structure of MG (Ni60Nb20Ta20) due to its high crystallization temperature with AlSi12 by gas pressure infiltration resulting in a novel MMC. X-ray diffraction measurements confirm that no crystallization occurred during infiltration. Micrographs show a good infiltration quality and interfacial bonding between both phases. An increase in Young's modulus of 28% and compressive strength in the MMC can be achieved compared to the AlSi12-matrix.

金属玻璃(MG)因其无定形结构而具有高强度、硬度和弹性应变极限等显著特性。但它们也表现出低延展性和脆性,因此不太适合用于整体元件。因此,MG 作为韧性基体中的增强相具有很大的应用潜力。特别是互穿金属基复合材料(MMC),因为 MG 的金属特性可以实现良好的界面粘附性,互穿结构可以进一步提高机械性能。制造过程中的温度必须低于 MG 的结晶温度。迄今为止,互穿式 MMC 都是通过在金属基泡沫塑料中渗入 MG 来制造的,这要求基体具有较高的熔化温度,因此不包括轻质金属。在这项工作中,由于 MG(Ni60Nb20Ta20)的结晶温度较高,因此可以通过气压渗透将其与 AlSi12 一起渗透到开放多孔晶格结构中,从而制造出新型 MMC。X 射线衍射测量证实,在浸润过程中没有发生结晶。显微照片显示,两相之间的浸润质量和界面结合良好。与 AlSi12 基质相比,MMC 的杨氏模量和抗压强度提高了 28%。


Concurrent stacking sequence and layout optimization of stiffened composite plates using a spectral element method and an index-based optimization technique

Alan Salih, Shaban Nefize, Sendur Gullu Kiziltas, Bediz Bekir

doi:10.1016/j.compstruct.2023.117698

使用谱元法和基于指数的优化技术同时优化加劲复合板的堆叠顺序和布局

Stiffened composite panels are increasingly used in aerospace, marine, and automotive industries due to their lightweight and high-strength properties. However, determining the optimal stacking sequence and/or layout of stiffeners concurrently while adhering to manufacturing guidelines and empirical rules is challenging. To address this issue, we propose a novel one-step optimization framework that couples a highly accurate and computationally efficient spectral element modeling technique with an index-based optimization approach that inherently satisfies the manufacturing guideline and empirical rules. Spectral element modeling (SEM) combines the high accuracy of spectral (meshless) methods with the geometric flexibility of finite element methods. To determine the optimal design, an index-based optimization is proposed to decrease the number of design variables and remove the constraints. We demonstrated the accuracy and computational performance of SEM with results obtained by finite element analysis on composite laminates with and without a cutout. Finally, we applied the proposed optimization framework to various stiffened composite (balanced and symmetric) laminates of up to 200 plies to demonstrate its capability and efficiency.

由于具有轻质高强的特性,加劲复合板越来越多地应用于航空航天、船舶和汽车行业。然而,在遵守制造准则和经验规则的同时,确定加劲件的最佳堆叠顺序和/或布局极具挑战性。为解决这一问题,我们提出了一种新颖的一步优化框架,该框架将高精度、高计算效率的谱元建模技术与基于索引的优化方法结合起来,从本质上满足了制造准则和经验规则。谱元建模(SEM)结合了谱(无网格)方法的高精度和有限元方法的几何灵活性。为了确定最佳设计,我们提出了一种基于指数的优化方法,以减少设计变量的数量并消除约束。我们通过对有切口和无切口的复合材料层压板进行有限元分析所获得的结果,证明了 SEM 的准确性和计算性能。最后,我们将提出的优化框架应用于多达 200 层的各种加劲复合材料(平衡和对称)层压板,以证明其能力和效率。


Post-Buckling Behavior and Collapse of Double-Double Composite Single Stringer Specimens

Vescovini A., Li C.X., Paz J., Jin B., Manes A., Bisagni C.

doi:10.1016/j.compstruct.2023.117699

双层复合单弦杆试件的屈曲后行为和坍塌

This paper presents the work on six single-stringer specimens manufactured using the card-sliding technique with non-crimp fabrics and adopting a Double-Double (DD) stacking sequence. These specimens, representative of sub-structure level components, are used to investigate post-buckling and failure in aerospace structures. Two specimens maintain a constant thickness cross-section, while four are tapered, two of which incorporate a Teflon insert in the stringer flange. All specimens are tested under compression loading conditions, inducing skin buckling, skin-stringer separation, and eventual collapse. Numerical simulations are validated by experimental results and serve to analyze the specimens behavior and the failure mode. The load versus displacement curves of both experimental tests and Finite Element Method (FEM) analyses are compared, along with the out-of-plane displacement field. Subsequently, the observed failure modes are discussed, focusing on the various mechanisms that occurred and considering the impact of flanges and stiffener tapering. Both the FEM simulations and experimental tests demonstrate good agreement, with the flanges tapering revealing notable results. This offers promising evidence of a viable solution to optimize aeronautical structures and enhance resistance to skin-stringer separation.

本文介绍了采用无皱织物的卡片滑动技术和双倍(DD)堆叠顺序制造的六个单弦试样。这些试样代表子结构级部件,用于研究航空航天结构的后屈曲和失效。两个试样保持恒定厚度的横截面,四个试样为锥形,其中两个试样在支撑翼缘中加入了特氟龙插入物。所有试样均在压缩加载条件下进行测试,以诱发蒙皮屈曲、蒙皮-弦杆分离和最终坍塌。实验结果对数值模拟进行了验证,并对试样的行为和破坏模式进行了分析。比较了实验测试和有限元法(FEM)分析的载荷与位移曲线以及平面外位移场。随后,对观察到的失效模式进行了讨论,重点是发生失效的各种机理,并考虑了法兰和加劲件锥度的影响。有限元模拟和实验测试均显示出良好的一致性,其中法兰锥度的结果尤为显著。这为优化航空结构和提高抗蒙皮弦杆分离能力提供了可行的解决方案。


A Dovetail Core Design for Joints in Composite Sandwich Structures

Aqel Rawan, Severson Patrick, Elhajjar Rani

doi:10.1016/j.compstruct.2023.117700

复合材料夹层结构接缝的燕尾芯设计

The increase in the size of composite sandwich structures requires the introduction of core splices to join various segments. In this study, a novel core splice joint configuration is studied and proposed for composite sandwich structures of thick aluminum-based honeycomb core and facesheets made from carbon fibers and epoxy matrix. Experimental and numerical efforts investigate the impact of dovetail joints with different tenon angles on the auxiliary behavior of composite sandwich structures. The results are compared to conventional or straight-core splices without dovetail features. The core-splice interaction with the complete mechanical behavior of the system was assessed by subjecting the fabricated specimens to combinations of bending and shear forces. Additionally, 3D-finite element models compared normal and shear stresses in the splice material and the core/splice interface among the dovetail configurations considered. The study shows that depending on the dovetail joint detail, an ultimate strength increase between 13 to 51% is achieved compared to the strength from currently used straight joints. In terms of toughness, the dovetail specimens show a 2% to 35% higher toughness compared to the standard straight joints.

随着复合材料夹层结构尺寸的增大,需要采用芯材拼接来连接各个部分。本研究针对由厚铝基蜂窝芯材和由碳纤维及环氧基质制成的面材组成的复合材料夹层结构,研究并提出了一种新型芯材拼接接头结构。实验和数值研究了不同榫角的燕尾接头对复合材料夹层结构辅助行为的影响。实验结果与传统或无燕尾槽的直芯拼接进行了比较。通过对制作的试样施加弯曲力和剪切力组合,评估了芯材拼接与系统整体机械行为的相互作用。此外,三维有限元模型还比较了所考虑的燕尾槽配置中拼接材料和芯材/拼接界面的法向应力和剪切应力。研究结果表明,根据燕尾接头细节的不同,与目前使用的直接头相比,其极限强度可提高 13% 至 51%。在韧性方面,与标准直接头相比,燕尾槽试样的韧性提高了 2% 至 35%。


Form-finding of elastic gridshell based on spatial elastica model

WANG Xianheng, CHEN Cong, ZHANG Jinsong, QIU Xinming

doi:10.1016/j.compstruct.2023.117653

基于空间弹性模型的弹性网格壳的形状确定

In engineering design, elastic gridshells, which are composed of a number of elastic rods, are advantageous because they are lightweight, easy to construct, and low-cost as well as have a long-span space. However, the form-finding of a gridshell is challenging owing to the large deformation and strong geometric-nonlinearity of the structure. In this paper, a new form-finding method based on spatial elastica model (FMSE) is proposed. The deformations of elastic rods, obtained via the elliptic integral solution of spatial elastica, is integrated into the overall deformation of the gridshell. A set of transcendental equations is solved using the quasi-Newton method to ensure that the deformation of the gridshell satisfies the given boundary conditions. To validate the proposed FMSE method, desktop experiments (designed using the theory of Chebyshev nets) are performed on gridshells made of glass fiber reinforced polymer rods. The predictions of the FMSE method agree well with the experimental results. Accordingly, the proposed FMSE method is expected to have potential applications in elastic gridshells, on the investigations of form-finding, load-bearing capability, non-local deformation behavior, and also stability of structures.

在工程设计中,由许多弹性杆组成的弹性栅壳具有重量轻、易于建造、成本低以及跨度空间大等优点。然而,由于网格壳结构的大变形和强几何非线性,网格壳的形状搜索具有挑战性。本文提出了一种基于空间弹性模型(FMSE)的全新找形方法。通过空间弹性椭圆积分求解得到的弹性杆的变形被整合到网格壳的整体变形中。使用准牛顿法求解一组超越方程,以确保网格壳的变形满足给定的边界条件。为了验证所提出的 FMSE 方法,在玻璃纤维增强聚合物棒制成的网格壳上进行了桌面实验(利用切比雪夫网理论设计)。FMSE 方法的预测结果与实验结果非常吻合。因此,所提出的 FMSE 方法有望应用于弹性网格壳,研究结构的寻形、承载能力、非局部变形行为以及稳定性。


Design and optimization of the dual-functional lattice-origami metamaterials

Jiang Tengjiao, Han Sihao, Han Qiang, Li Chunlei

doi:10.1016/j.compstruct.2023.117670

双功能晶格原形超材料的设计与优化

This study proposes a multi-scale composite lattice-origami metamaterial (MCLOM) to achieve excellent bandgap characteristics and energy absorption capacities. The MCLOMs are constructed by considering the high impedance mismatch of lattice structures, the spatial deformability of origami structures, and the tunability of the components in multi-scale composite materials. Firstly, elastic wave propagation characteristics are analyzed in the Bloch wave framework, revealing the realization of complete bandgaps and their generation mechanism by mode shape analysis and transmission spectrum. Subsequently, an optimization framework integrating the particle swarm optimization (PSO) algorithm is developed to maximize the first bandgap’s bandwidth by adjusting various component parameters. Under optimal distribution, the proposed metamaterials achieve remarkable improvements of 289% and 271% in the design objectives of two lattice-origami metamaterials with 90° dihedral angle compared to the initial distribution. It can be demonstrated that non-uniform distributions of multi-scale composite materials are dramatically effective for broadband wave attenuation. Additionally, while striving to widen the bandgap, the energy absorption capacities of structures are also crucial. The effect of the distribution of multi-scale composite materials with the optimal bandgap on the energy absorption performance is investigated. The results reveal that the optimal distribution of the lattice-origami metamaterials yields notable improvements of 48.26% and 34.86% under low-velocity impact, and 37.41% and 25.19% under medium-velocity impact. This work presents innovative concepts and approaches for devising and implementing novel dual-functional metamaterials, undoubtedly propelling the continual progress of material science and engineering technology in the times ahead.

本研究提出了一种多尺度复合晶格-折纸超材料(MCLOM),以实现优异的带隙特性和能量吸收能力。考虑到晶格结构的高阻抗失配性、折纸结构的空间变形性以及多尺度复合材料中各成分的可调谐性,构建了 MCLOM。首先,在布洛赫波框架下分析了弹性波的传播特性,通过模形分析和透射谱揭示了完整带隙的实现及其产生机制。随后,结合粒子群优化(PSO)算法建立了一个优化框架,通过调整各种组件参数来最大化第一带隙的带宽。在最佳分布条件下,与初始分布相比,所提出的超材料在两个具有 90° 二面角的晶格原形超材料的设计目标上分别实现了 289% 和 271% 的显著改进。这表明,多尺度复合材料的非均匀分布对宽带波衰减具有显著效果。此外,在努力拓宽带隙的同时,结构的能量吸收能力也至关重要。本文研究了具有最佳带隙的多尺度复合材料的分布对能量吸收性能的影响。结果表明,晶格原形超材料的最佳分布在低速撞击下分别产生了 48.26% 和 34.86% 的显著改善,在中速撞击下分别产生了 37.41% 和 25.19% 的显著改善。这项研究提出了设计和实现新型双功能超材料的创新理念和方法,无疑将推动材料科学和工程技术在未来时代的不断进步。


Multi-phase metamaterials containing framework structures to program thermal expansion and mechanical performances

Wang Kaiyu, Chen Jiaxin, Wei Kai, Wang Rong, Yang Xujing

doi:10.1016/j.compstruct.2023.117671

包含框架结构的多相超材料可实现热膨胀和机械性能编程

Due to suffering the thermal and mechanical loadings simultaneously, metamaterials integrating with the customizable coefficient of thermal expansion (CTE) and high mechanical performances are desirable to ensure the thermal and structural stabilities in engineering devices. Hence, various multi-phase metamaterials with programmable CTEs and mechanical performances were developed. Specifically, inspired by the mixture of multiple phases in composites and the rigid rotations of framework structures in materials with negative CTE, a typical pyramid unit was introduced. Additionally, two series of metamaterials were systematically designed, which were constructed in batches from different units through the matrix transformation method. The CTEs of the metamaterials were theoretically established and analyzed. Besides, mechanical performances, including relative density, stiffness and strength were also calculated and discussed. The results suggest that the directionality and magnitude of CTEs are determined by the constructing principle of multi-fold rotations. In addition, the large ranges of programmable CTEs and high load-bearing capacity are available in the devised metamaterials by reasonably modulating the geometrical parameters. The thermal expansion and mechanical performances of the metamaterials could be synchronously programmed. The diversity of the phase configurations and geometrical architectures in the metamaterials offers the opportunity to satisfy manifold requirements in different applications.

由于要同时承受热负荷和机械负荷,具有可定制热膨胀系数(CTE)和高机械性能的超材料是确保工程设备热稳定性和结构稳定性的理想选择。因此,各种具有可编程热膨胀系数和机械性能的多相超材料应运而生。具体来说,受复合材料中多相混合以及负 CTE 材料中框架结构刚性旋转的启发,引入了典型的金字塔单元。此外,还系统地设计了两个系列的超材料,通过矩阵变换方法由不同单元分批构建而成。理论上确定并分析了超材料的 CTE。此外,还计算并讨论了超材料的力学性能,包括相对密度、刚度和强度。结果表明,CTE 的方向性和大小由多倍旋转的构造原理决定。此外,通过合理调节几何参数,设计出的超材料还具有大范围的可编程 CTE 和高承载能力。超材料的热膨胀和机械性能可同步编程。超材料相位配置和几何结构的多样性为满足不同应用的多方面要求提供了机会。


Composites Part A: Applied Science and Manufacturing

Observations of Wrinkling in Non-Crimp Fabrics during Multi-Ply Stack Forming using In situ XCT Scanning

Jimenez-Martin Claudia, Maes Vincent, Rosini Sebastian, Smith Ronan, Sinclair Ian, Mavrogordato Mark, McMahon Turlough, Kratz James

doi:10.1016/j.compositesa.2023.107880

使用原位 XCT 扫描观察多层堆叠成形过程中非起皱织物的起皱情况

This paper shows the internal evolution of wrinkles occurring in a single diaphragm forming process using time-resolved in situ XCT scanning. Forming trials were carried out over a curved C-spar geometry using Non-Crimp Fabric (NCF) plies of 45°/135°, 0°/90° and 0°/45° orientations arranged in single-orientation and mixed-orientation stacks. Results show most of the diaphragm movement and change in wrinkle size, shape, and location occurs in the early application (<0.1 bar) of vacuum. The further application of vacuum shows consolidation, with wrinkle size decreasing but shape and location remaining largely unchanged. Single-orientation stacks of 45°/135° plies showed the closest resemblance between initial and final wrinkling, while mixed-orientation stacks showed complex wrinkling due to the 0° plies creating internal ply separation due to excess length. Overall, the study shines a light on the internal interaction between layers that occurs during wrinkling, showing mechanisms only observable with XCT.

本文利用时间分辨原位 XCT 扫描技术展示了单隔膜成形过程中皱纹的内部演变过程。成型试验是在弯曲的 C 型支柱几何形状上进行的,使用的是以单一方向和混合方向堆叠排列的 45°/135°、0°/90° 和 0°/45° 方向的无皱褶织物 (NCF) 层。结果表明,隔膜的大部分移动以及皱纹大小、形状和位置的变化都发生在施加真空的初期(小于 0.1 巴)。进一步施加真空后会出现巩固,皱纹的大小会减小,但形状和位置基本保持不变。由 45°/135° 层组成的单取向叠层显示出初始和最终皱纹之间最接近的相似性,而混合取向叠层则显示出复杂的皱纹,这是因为 0° 层由于长度过长而产生了内部层间分离。总之,这项研究揭示了起皱过程中发生的层间内部相互作用,显示了只有 XCT 才能观察到的机制。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemInspireDeform振动断裂复合材料非线性航空航天船舶轨道交通汽车理论材料多尺度试验人工智能
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【新文速递】2023年11月11日复合材料SCI期刊最新文章

今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 4 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇Composite StructuresPullout behavior of recycled macro fibers in the cementitious matrix: analytical model and experimental validationYUAN Hong, FAN Y.C., YOU X.M., FU Bing, ZOU Q.Q.doi:10.1016/j.compstruct.2023.117690水泥基质中再生大纤维的拉拔行为:分析模型和实验验证A novel mechanical recycling method has been recently developed in the authors’ group for processing waste glass fiber-reinforced polymer (GFRP) composites into macro fibers, which are then incorporated into concrete to produce green fiber-reinforced concrete (FRC). The present study has been conducted for facilitating the characterization of the tensile properties of macro fiber reinforced concrete (MFRC). A trilinear bond-slip model based on the shear-lag theory has first been refined by introducing a slip coefficient to consider different slip behaviors at the final pullout stages. Such a refined trilinear bond-slip model is suitable for describing the bond-slip behavior of the recycled macro fibers embedded in the cementitious matrix. The bond parameters are obtained through an inverse analysis, in which an improved particle swarm optimization algorithm (PSO) is used. The predicted force-end slip curves are compared with the pullout test results, and a good agreement is observed counterparts with the integral absolute error (IAE) ranging from 3.05%-5.52%, demonstrating the feasibility of the proposed analytical model. A parametric study is finally conducted to examine the sensitivity of different parameters including the fiber geometries and bond properties on the pullout behavior of the macro fibers.作者的研究小组最近开发了一种新的机械回收方法,用于将废玻璃纤维增强聚合物(GFRP)复合材料加工成大纤维,然后将其融入混凝土中,生产出绿色纤维增强混凝土(FRC)。本研究的目的是分析大纤维增强混凝土(MFRC)的拉伸特性。基于剪切滞后理论的三线性粘结滑移模型首先通过引入滑移系数进行了改进,以考虑最后拉拔阶段的不同滑移行为。这种改进后的三线粘结滑移模型适用于描述嵌入水泥基质中的再生大纤维的粘结滑移行为。粘结参数是通过反分析获得的,其中使用了改进的粒子群优化算法(PSO)。将预测的力端滑移曲线与拉拔测试结果进行比较,发现两者之间存在很好的一致性,其积分绝对误差(IAE) 在 3.05%-5.52% 之间,证明了所提分析模型的可行性。最后还进行了参数研究,以检验不同参数(包括纤维几何形状和粘结性能)对宏纤维拉拔行为的敏感性。Ti-PEEK interpenetrating phase composites with minimal surface for property enhancement of orthopedic implantsXie Haiqiong, Chen Junjie, Liu Fei, Wang Rui, Tang Yichuan, Wang Yiru, Luo Tao, Zhang Kaifei, Cao Jiandoi:10.1016/j.compstruct.2023.117689 具有最小表面的 Ti-PEEK 互穿相复合材料,用于提高骨科植入物的性能Bioinspired interpenetrating phase composites (IPCs) present a promising strategy for augmenting the mechanical properties of materials, thereby synergistically enhancing the strength and fracture toughness of orthopedic implants. In this study, Ti6Al4V-PEEK IPCs were fabricated by pressing molten PEEK into additively manufactured Ti6Al4V scaffolds designed using minimal surface structures. The mutual spatial interpenetration and strong binding between Ti and PEEK were confirmed through CT detection and SEM analyses, revealing the presence of continuous constituents within biomimetic architectures. Due to interpenetration promoting interaction and efficient stress transfer of the two phases, IPCs enhances toughness and energy absorption by over 291% and 309% respectively while maintaining bone-compatible elastic modulus and higher strength. The mechanisms underlying stress dispersion, crack propagation resistance, and prolonged stress plateau period of IPCs were investigated through the utilization of digital image correlation (DIC) and finite element simulation techniques. Among the various types of IPCs investigated, Gyroid IPCs exhibit superior comprehensive mechanical properties, thereby facilitating the development of customized IPCs aimed at ensuring long-term stability in orthopedic implantation scenarios.受生物启发的互穿相复合材料(IPC)是增强材料力学性能的一种有前途的策略,可协同增强骨科植入物的强度和断裂韧性。在这项研究中,通过将熔融的 PEEK 压入采用最小表面结构设计的添加式制造的 Ti6Al4V 支架中,制造出了 Ti6Al4V-PEEK IPC。通过 CT 检测和 SEM 分析证实了 Ti 和 PEEK 之间的空间互穿和强结合,揭示了生物仿生结构中存在连续的成分。由于相互渗透促进了两相之间的相互作用和有效应力传递,IPCs 在保持骨兼容弹性模量和更高强度的同时,韧性和能量吸收分别提高了 291% 和 309%。通过利用数字图像相关(DIC)和有限元模拟技术,研究了 IPCs 的应力分散、抗裂纹扩展和应力高原期延长的机理。在所研究的各种类型的 IPC 中,Gyroid IPC 表现出更优越的综合机械性能,从而促进了定制 IPC 的开发,以确保骨科植入应用中的长期稳定性。Nonlinear electromechanical bending of bi-modular piezoelectric laminated beamsZeng Shan, Yu Zhiyong, Wang Fei, Wang Kaifa, Wang Baolindoi:10.1016/j.compstruct.2023.117718双模块压电叠层梁的非线性机电弯曲In this paper, the nonlinear electromechanical bending of a bi-modular piezoelectric laminated beam is studied based on the principle of minimum potential energy and the Adomian decomposition method. The different tensile-compressive Young’s modulus of the core and piezoelectric layers, and the different tensile-compressive piezoelectric coefficients are considered. The electromechanical governing equations and related boundary conditions are obtained by using the principle of minimum potential energy. The deflection, neutral layer and interlaminar stresses of the beam are solved by the Adomian decomposition method and the iterative method, and verified by the finite element model and Galerkin&#39;s method. Results show that the applied voltage and the bi-modular characteristics affect the position of the neutral layer and the interlaminar stresses. Compared with the bi-modular properties of the core layer, the influences of the bi-modular properties of the piezoelectric layer on the neutral layer are relatively unobvious. In addition, the interlaminar stresses between the piezoelectric layer and core layer can be increased or decreased, depending on the relative magnitude of the applied voltage ratio and the bi-modular ratio. The results obtained are helpful for the analysis of the electromechanical coupling mechanism and design of piezoelectric composites and structures with bi-modular characteristics.本文基于最小势能原理和 Adomian 分解法研究了双模块压电层叠梁的非线性机电弯曲。考虑了芯层和压电层不同的拉伸-压缩杨氏模量以及不同的拉伸-压缩压电系数。利用最小势能原理得到了机电控制方程和相关边界条件。采用 Adomian 分解法和迭代法求解了梁的挠度、中性层和层间应力,并通过有限元模型和 Galerkin 方法进行了验证。结果表明,外加电压和双模块特性会影响中性层的位置和层间应力。与芯层的双模块特性相比,压电层的双模块特性对中性层的影响相对不明显。此外,压电层与芯层之间的层间应力可以增加或减少,这取决于外加电压比和双模态比的相对大小。所获得的结果有助于分析机电耦合机制和设计具有双模块特性的压电复合材料和结构。Composites Part A: Applied Science and ManufacturingAnisotropy Behavior of Liquid Metal Elastomer Composites with Both Enhanced Thermal Conductivity and Crack Resistance by Direct Ink WritingXu Peihua, Zhu Lida, Zhao Zixu, Yang Zhichao, Ning Jinsheng, Xue Pengsheng, Lu Haodoi:10.1016/j.compositesa.2023.107890通过直接油墨写入法增强导热性和抗裂性的液态金属弹性体复合材料的各向异性行为Liquid metal elastomer composites (LMEC) have broad application prospects in flexible devices, but the research on the basic processes of DIW for LMEC and the properties of DIW-ed LMEC is lacking. In this study, liquid metal (LM) is added to silicone elastomers such as Polydimethylsiloxane (PDMS), and the effect of LM volume fraction on ink rheology is investigated. Results show that the storage modulus of ink is lower than its loss modulus, which is not conducive to self-support formation. Therefore, fluorination is adopted to treat the silicon dioxide substrate used, thereby reducing the deformation rate of the printed structure to below 110%. The results of properties show that the crack resistance and thermal conductivity of soft elastomers increase with the LM volume fraction. Additionally, the tensile properties of PDMS printed via DIW exhibit significant anisotropy parallel and perpendicular to the scanning direction, and that the addition of LM droplets reduces the anisotropy. And with the increase of curing temperature and LM droplet size, the stretchability of DIW-ed LMEC in both directions decreases, but only LMEC samples cured at 140℃ exhibit significant anisotropy. This study provides guidance pertaining to the basic process and printing directions for the application of DIW in the manufacture of LMEC equipment.液态金属弹性体复合材料(LMEC)在柔性设备中具有广阔的应用前景,但有关液态金属弹性体复合材料 DIW 的基本工艺以及 DIW 后液态金属弹性体复合材料性能的研究却十分缺乏。本研究将液态金属(LM)添加到聚二甲基硅氧烷(PDMS)等有机硅弹性体中,并研究了 LM 体积分数对油墨流变性的影响。结果表明,油墨的存储模量低于其损耗模量,不利于自支撑的形成。因此,采用氟化处理所用的二氧化硅基底,从而将印刷结构的变形率降低到 110% 以下。性能结果表明,软弹性体的抗裂性和导热性随 LM 体积分数的增加而提高。此外,通过 DIW 印刷的 PDMS 的拉伸性能在平行和垂直于扫描方向上表现出明显的各向异性,而添加 LM 液滴则会降低这种各向异性。随着固化温度和 LM 液滴大小的增加,DIW 印刷的 LMEC 在两个方向上的拉伸性都会降低,但只有在 140℃ 下固化的 LMEC 样品才会表现出明显的各向异性。这项研究为在 LMEC 设备制造中应用 DIW 的基本工艺和印刷方向提供了指导。Evolutionary Algorithm-Based Integrated Design of Material-Structural Microwave Absorption Using Material ExtrusionZhang Yuhui, Shan Mengtong, Lei Han, Zhao Pengzhen, Yu Chen, Huang Yixingdoi:10.1016/j.compositesa.2023.107891基于进化算法的材料-结构微波吸收综合设计(材料挤压法The development of electromagnetic wave absorbing materials and structures holds significant importance in fields such as aerospace and electronic communications. Traditional absorbing coatings have poor mechanical load-bearing capacity and struggle to meet the requirements of lightweight applications. On the other hand, the research on lossy dielectric absorbers is limited by process constraints, making it difficult to fabricate complex configurations, thereby greatly restricting their broadband absorption performance. In this study, a functional absorbing composite filament was developed using material extrusion technique. A magnetic lossy four-layer gradient honeycomb metastructure was designed, which enables effective absorption in the frequency range of 6.09-37.18 GHz within a thickness of 16 mm. The effective absorption bandwidth covers 81.82% in the frequency range of 2-40 GHz. This broadband absorbing design achieves the integration of material functionality and structural design by additive manufacturing, enabling effective absorption across a broad frequency range.电磁波吸收材料和结构的开发在航空航天和电子通信等领域具有重要意义。传统的吸波涂层机械承载能力差,难以满足轻质应用的要求。另一方面,有损电介质吸收体的研究受到工艺限制,难以制造复杂的结构,从而大大限制了其宽带吸收性能。本研究利用材料挤压技术开发了一种功能性吸波复合丝。设计了一种磁性损耗四层梯度蜂窝结构,在厚度为 16 毫米的范围内实现了 6.09-37.18 GHz 频率范围内的有效吸收。在 2-40 GHz 频率范围内,有效吸收带宽达到 81.82%。这种宽带吸收设计通过增材制造实现了材料功能与结构设计的整合,从而实现了宽频率范围内的有效吸收。Hybrid assembly based on nanomaterial reinforcement for multifunctionalized skin-like flexible sensorsLv Xiaohua, Ling Yufei, Tang Kaiyou, Qiao Changyu, Fu Lihua, Xu Chuanhui, Lin Baofeng, Wei Yendoi:10.1016/j.compositesa.2023.107892基于纳米材料加固的混合组件,用于多功能类肤柔性传感器Currently, the inferior mechanical strength, weak environmental adaptability, and limited functionality of conductive hydrogel significantly impede its potential application in wearable sensors. Here, &#39;&#39;hard&#39;&#39; acrylic bentonite (AABT) intercalated nanostructures and silver-modified polydopamine (PDA@Ag) particles are encapsulated in a &#39;&#39;soft&#39;&#39; polyacrylic acid matrix in a water/glycerol binary solvent system. This strategy successfully realized the high matched skin modulus (58 kPa), high stress (371 kPa) and strain (1025%). The PDA@Ag particles retains rich phenolic hydroxyl groups imitating mussel to provide strong adhesion (29.12 kPa). These particles also give the hydrogel long time antibacterial properties (3 days), while demonstrating excellent biosafety. The introduction of a binary system of water/glycerol effectively suppresses the evaporation and crystallization of water, thereby maintaining sensing performance above 82% even under extreme conditions. This hydrogel achieves integrated applications of multifunctionality and multi-environmental adaptability, providing a new idea for the development of next-generation skin-like hydrogel sensors.目前,导电水凝胶的机械强度低、环境适应性弱、功能有限,这些都严重阻碍了其在可穿戴传感器中的潜在应用。在这里,&quot;硬 &quot;丙烯酸膨润土(AABT)插层纳米结构和银改性聚多巴胺(PDA@Ag)颗粒被封装在水/甘油二元溶剂体系中的 &quot;软 &quot;聚丙烯酸基质中。这种策略成功实现了高匹配表皮模量(58 kPa)、高应力(371 kPa)和应变(1025%)。PDA@Ag 颗粒保留了仿贻贝的丰富酚羟基,提供了强大的粘附力(29.12 kPa)。这些颗粒还赋予了水凝胶长效抗菌特性(3 天),同时表现出卓越的生物安全性。水/甘油二元体系的引入有效抑制了水的蒸发和结晶,因此即使在极端条件下也能保持 82% 以上的传感性能。这种水凝胶实现了多功能和多环境适应性的综合应用,为开发下一代类皮肤水凝胶传感器提供了新思路。Dual-modulus 3D Printing Technology for Magnetorheological Metamaterials-Part II: Negative Regulation Theory and ApplicationLou Congcong, Liu Bing, Cao Xufeng, Gao Liang, Xuan Shouhu, Deng Huaxia, Gong Xinglongdoi:10.1016/j.compositesa.2023.107893磁流变超材料的双模量三维打印技术--第二部分:负调控理论与应用Metamaterials are artificially structured periodic materials that have remarkable property of wave attenuation in bandgaps. However, metamaterials with adjustable and low-frequency bandgap are still challenge in traditional method. In this work, a novel magnetorheological metamaterial (MRM) with negative regulation and low-frequency bandgaps was fabricated by dual-modulus 3D printing technology. The bandgaps of negative regulation MRM were analyzed theoretically by using the mass-spring model. As a result, the starting frequency of bandgap reduced by 37.6% and ending frequency increased by 47.8% under external magnetic field. Moreover, the propagation characteristics of longitudinal wave in negative regulation MRM were also studied and the results indicated that the stiffnesses were magnetic-related, and the bandgap can be tuned substantially under external magnetic field. This work presented a negative regulation MRM that the bandgap was broadened and moved to lower frequency under the external magnetic field, showing a great potential in the field of vibration isolation.超材料是一种人工结构的周期性材料,在带隙中具有显著的波衰减特性。然而,具有可调低频带隙的超材料仍然是传统方法的挑战。在这项工作中,利用双模量三维打印技术制作了一种具有负调控和低频带隙的新型磁流变超材料(MRM)。利用质量弹簧模型对负调节超材料的带隙进行了理论分析。结果表明,在外加磁场作用下,带隙的起始频率降低了 37.6%,终止频率提高了 47.8%。此外,还研究了负调压磁共振中纵波的传播特性,结果表明刚度与磁有关,带隙在外加磁场作用下可大幅调整。这项研究提出了一种负调控磁共振,其带隙在外加磁场的作用下被拓宽并向低频移动,在隔振领域显示出巨大的潜力。Composites Part B: EngineeringRecycled carbon fiber potential for reuse in carbon fiber/PA6 composite partsJeantet Louis, Regazzi Arnaud, Perrin Didier, Pucci Monica Francesca, Corn Stéphane, Quantin Jean-Christophe, Ienny Patrickdoi:10.1016/j.compositesb.2023.111100 再生碳纤维在碳纤维/PA6 复合材料部件中的再利用潜力Pyrolysis reclaiming is the most promising process to treat high volumes of composite waste with an advantageous carbon footprint. This paper aims to compare pyrolysis reclaimed carbon fibers (RCF) to virgin sized fibers (VF) and de-sized fibers (VFT) in their capability to bond to a polyamide 6 matrix. Micromechanical tensile testing of single fiber samples of the three fiber types was conducted. A minor reduction in tensile strength and an unchanged elastic modulus of the RCF compared to VF was observed. Scanning electron microscopy and atomic force microscopy scans were used to evaluate the morphology of the fibers. To evaluate the surface energy of the fibers, tensiometric testing was conducted. RCF showed a better adhesion capability compared to VFT through higher total surface energy. Moreover, X-ray spectrophotometry scans highlighted a higher proportion of functional groups at the RCF surface compared to VFT. Finally, pull-out tests underlined a decrease of the interfacial shear strength of RCF and VFT by 35 % compared to VF. Overall, this study’s results further the understanding of the impact of the pyrolysis reclaiming process on RCF mechanical and adhesion properties.热解再生是处理大量复合材料废料的最有前途的工艺,同时还具有良好的碳足迹。本文旨在比较热解再生碳纤维(RCF)与原生尺寸纤维(VF)和去尺寸纤维(VFT)与聚酰胺 6 基质的粘合能力。对三种纤维的单纤维样品进行了微机械拉伸测试。与 VFT 相比,RCF 的拉伸强度略有降低,弹性模量保持不变。扫描电子显微镜和原子力显微镜扫描用于评估纤维的形态。为了评估纤维的表面能,还进行了张力测试。与 VFT 相比,RCF 通过更高的总表面能显示出更好的粘附能力。此外,X 射线分光光度扫描显示,与 VFT 相比,RCF 表面的官能团比例更高。最后,拉出试验表明,与 VF 相比,RCF 和 VFT 的界面剪切强度降低了 35%。总之,这项研究的结果进一步加深了人们对热解再生工艺对 RCF 机械和粘附性能影响的理解。Composites Science and TechnologyA simple rheological method for the experimental assessment of the fiber percolation threshold in short fiber biocompositesVitiello Libera, Salzano de Luna Martina, Ambrogi Veronica, Filippone Giovannidoi:10.1016/j.compscitech.2023.110345 用于实验评估短纤维生物复合材料纤维渗流阈值的简单流变学方法The identification of the percolation threshold (Φc) in short fiber composites is a challenging problem in Composite Science. Above Φc the fibers form a continuous network that causes substantial changes in mechanical and transport properties. Besides, percolation of natural fibers in biodegradable polymer matrices allows water and other pro-degradative species to access the inner parts of the material from the external environment, accelerating biodegradation. Whether such a speeding up is desired or not, assessing Φc in composites is of utmost importance. Unfortunately, natural fibers are not conductive and exhibit highly variable shape and physical properties. This prevents the use of many experimental and theoretical approaches for the estimate of Φc. Here we propose an original rheological approach borrowed from the viscoelastic modelling of polymer nanocomposites. The method was applied to two systems made of poly(lactic acid) filled with hemp or kenaf fibers (average length &lt;500 μm, average length-to-diameter ratio &lt;5). The estimate of Φc (∼10.1 and 19.5 vol% for the hemp- and kenaf-based composite, respectively) required a single set of simple linear viscoelastic measurements, and the computed values were in good agreement with those obtained through time-consuming (measurement times &gt;3 weeks) dielectric spectroscopy analyses (∼10.1 and 18.5 vol%).确定短纤维复合材料中的渗流阈值(Φc)是复合材料科学中一个具有挑战性的问题。超过 Φc 时,纤维会形成连续的网络,从而导致机械和传输性能发生重大变化。此外,天然纤维在可生物降解聚合物基质中的渗滤作用可使水和其他促降解物质从外部环境进入材料内部,从而加速生物降解。无论是否希望加速降解,评估复合材料中的Φc 都至关重要。遗憾的是,天然纤维并不导电,而且其形状和物理性质变化很大。这使得许多实验和理论方法无法用于估算 Φc。在此,我们从聚合物纳米复合材料的粘弹性建模中借鉴了一种独创的流变学方法。我们将该方法应用于由聚乳酸填充麻纤维或槿麻纤维(平均长度小于 500 μm,平均长径比小于 5)制成的两个系统。只需进行一组简单的线性粘弹性测量,即可估算出Φc(麻基和槿麻基复合材料的Φc分别为 10.1 ∼ 10.1 和 19.5 vol%),计算值与耗时(测量时间大于 3 周)的介电光谱分析结果(Φc 为 10.1 ∼ 10.1 和 18.5 vol%)十分吻合。来源:复合材料力学仿真Composites FEM

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