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【新文速递】2023年11月19日固体力学SCI期刊最新文章

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今日更新:International Journal of Solids and Structures 2 篇,Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 4 篇

International Journal of Solids and Structures

An enhanced simplified model for dynamic analysis of deployable Bennett linkages considering link cross-sectional size and contact

Zheng Yanfeng, Li Siyuan, Zhang Jingyao, Luo Yaozhi

doi:10.1016/j.ijsolstr.2023.112583

考虑到链节横截面尺寸和接触情况的可部署贝内特链节动态分析增强型简化模型

Deployable Bennett linkage has broad application prospects in engineering. Existing simplified models generally do not consider the link cross-sectional size and contact, and therefore, deviate from real-world Bennett linkages. This paper proposes an enhanced simplified model based on finite particle method (FPM) to consider link cross-sectional size and contact. Specifically, this model introduces virtual beams at the end cross-sections to consider the link cross-sectional size; furthermore, contacts between link surfaces, when Bennett linkage is fully folded or deployed, are considered by applying contact forces directly. The modeling methods for a single unit of Bennett linkage and an assembly are presented. The dynamic analysis method based on FPM is proposed for the enhanced simplified model, and the corresponding beam element, revolute hinge element, and contact element are derived. The dynamic responses of the unit of Bennett linkage are compared to those by the fine model to verify the proposed enhanced simplified model, and the influences of structural parameters are further investigated. The assembly of Bennett linkage is also analyzed to demonstrate the feasibility of the proposed method in the assembly of large-scale units. The numerical results demonstrate that the proposed method is effective and provides a promising approach for dynamic analysis of large-scale deployable Bennett linkages.

可部署贝内特连杆在工程领域具有广阔的应用前景。现有的简化模型一般不考虑连杆横截面尺寸和接触情况,因此与实际的贝内特连杆存在偏差。本文提出了一种基于有限粒子法(FPM)的增强简化模型,以考虑连杆横截面尺寸和接触情况。具体来说,该模型在末端横截面上引入了虚拟梁,以考虑连杆横截面尺寸;此外,当贝内特连杆完全折叠或展开时,连杆表面之间的接触是通过直接施加接触力来考虑的。本文介绍了单个贝内特连杆和组件的建模方法。针对增强型简化模型,提出了基于 FPM 的动态分析方法,并推导出相应的梁元素、旋转铰链元素和接触元素。将 Bennett 连杆单元的动态响应与精细模型的动态响应进行比较,以验证所提出的增强简化模型,并进一步研究了结构参数的影响。此外,还分析了贝内特连杆的装配情况,以证明所提方法在大型单元装配中的可行性。数值结果表明,所提出的方法是有效的,为大型可部署贝内特连杆的动态分析提供了一种可行的方法。


Multicell Thin-walled Method for Solid Multimaterial Beams

Ramírez-Luis Vicente, Hernández-Moreno Hilario, Susarrey-Huerta Orlando

doi:10.1016/j.ijsolstr.2023.112585

固体多材料梁的多孔薄壁法

In this paper we developed the Multicell Thin-walled Method for Solid Multimaterial Beams, which combines structural idealization used in aircraft components, thin-walled beam theory and homogenization techniques from composite materials applied to discrete models, to obtain the cross-section stress fields of solid beams made of multiple orthotropic and isotropic materials. This method idealizes a solid multimaterial cross-section as a multicell thin-walled section to accurately obtain complex stress fields while significantly reducing the solution time, as well as the computational cost, when compared to classical 3D finite element analyses. This method was implemented in a computer program and three examples were analyzed to validate results with the finite element method. Both methods show almost identical results in regions not affected by local disturbances.

在本文中,我们开发了用于实心多材料梁的多孔薄壁方法,该方法结合了飞机部件中使用的结构理想化、薄壁梁理论以及应用于离散模型的复合材料均质化技术,以获得由多种正交和各向同性材料构成的实心梁的横截面应力场。与传统的三维有限元分析相比,该方法将固体多材料横截面理想化为多单元薄壁截面,可精确获得复杂的应力场,同时大大减少求解时间和计算成本。该方法已在计算机程序中实施,并对三个实例进行了分析,以验证与有限元方法的结果。在不受局部扰动影响的区域,两种方法显示出几乎相同的结果。


Journal of the Mechanics and Physics of Solids

A mechanically-derived contact model for adhesive elastic-perfectly plastic particles, Part I: Utilizing the method of dimensionality reduction

Zunker William, Kamrin Ken

doi:10.1016/j.jmps.2023.105492

粘性弹性完全可塑颗粒的机械接触模型,第一部分:利用降维方法

In this two part series (Zunker and Kamrin, 2024), we present a contact model able to capture the response of interacting adhesive elastic-perfectly plastic particles under a variety of loadings. In Part I, we focus on elastic through fully-plastic contact with and without adhesion. For these contact regimes the model is built upon the method of dimensionality reduction which allows the problem of a 3D axisymmetric contact to be mapped to a corresponding problem of a 1D rigid indenter penetrating a bed of independent Hookean springs. Plasticity is accounted for by continuously varying the 1D indenter profile subject to a constraint on the contact pressure. Unloading falls out naturally, and simply requires lifting the 1D indenter out of the springs and tracking the force. By accounting for the incompressible nature of this plastic deformation, the contact model is able to capture multi-neighbor dependent effects such as increased force and formation of new contacts. JKR type adhesion is recovered seamlessly within the method of dimensionality reduction by simply allowing the springs to ‘stick’ to the 1D indenter’s surface. Because of the mechanics-focused formulation of the contact model, only a few physical inputs describing the interacting particles are needed: particle radius, Young’s modulus, Poisson ratio, yield stress, and effective surface energy. The contact model is validated against finite element simulations and analytic theory—including Hertz’s contact law and the JKR theory of adhesion. These comparisons show that the proposed contact model is able to accurately capture plastic displacement, average contact pressure, contact area, and force as a function of displacement for contacts as well as particle volume within the elastic to fully-plastic regimes.

在本系列的两部分(Zunker 和 Kamrin,2024 年)中,我们介绍了一个接触模型,该模型能够捕捉到在各种载荷下相互作用的粘性弹性全塑颗粒的响应。在第一部分中,我们重点讨论了有粘性和无粘性的弹性接触和全塑接触。对于这些接触状态,模型建立在降维方法的基础上,该方法可将三维轴对称接触问题映射为一维刚性压头穿透独立胡克弹簧床的相应问题。通过连续改变一维压头的轮廓,并对接触压力进行约束,可对塑性进行解释。卸载自然产生,只需将一维压头抬出弹簧并跟踪力即可。通过考虑这种塑性变形的不可压缩性,接触模型能够捕捉多邻域效应,例如力的增加和新接触的形成。通过简单地让弹簧 "粘附 "在一维压头表面,JKR 型粘附可在降维方法中无缝恢复。由于接触模型是以力学为重点的表述,因此只需要几个描述相互作用颗粒的物理输入:颗粒半径、杨氏模量、泊松比、屈服应力和有效表面能。接触模型通过有限元模拟和分析理论(包括赫兹接触定律和 JKR 粘附理论)进行了验证。这些比较结果表明,所提出的接触模型能够准确捕捉到塑性位移、平均接触压力、接触面积和力与接触位移的函数关系,以及弹性至完全塑性状态下的颗粒体积。


International Journal of Plasticity

Micromechanical properties and deformation behavior of the constituent phases in 3rd generation complex phase AHSS: In-situ neutron experiment and crystal plasticity simulation

Tran Minh Tien, Nguyen Xuan Minh, Kim Hyunki, Chae Hobyung, Woo Wanchuck, Lee Ho Won, Kim Dong-Kyu

doi:10.1016/j.ijplas.2023.103812

第三代复相 AHSS 中各组成相的微机械特性和变形行为:原位中子实验和晶体塑性模拟

This paper investigated the micromechanical properties and deformation behavior of the constituent phases in 3rd generation (GEN) complex phase advanced high-strength steel (AHSS). The hybrid method was a comprehensive combination of uniaxial tensile test with digital image correlation (DIC), electron backscatter diffraction (EBSD), in-situ neutron diffraction (NED) and crystal plasticity finite element method (CPFEM). Results reveal that the microstructure of 3rd GEN AHSS exhibits a complex phase of ferrite (46.2%), bainite (36.1%), martensite (9.4%) and austenite (8.3%), which would be promising microstructure in the development of new-generation complex phase AHSS. The significant findings are: 1) excellent ductility is obtained while high strength is preserved despite small martensite volume fraction, which can reduce the tendency of martensite cracking; 2) macroscopic stress-strain relationships and microscopic hardening properties of constituent phases are successfully determined, which are very important for predicting the overall performance of complex phase AHSS; 3) presence of bainite with high volume fraction plays a critical role in inducing plastic strain localization in ferrite, resulting in the heterogeneous stress/strain distribution. It is disclosed that pronounced strain localization is mostly initiated in ferrite grains while the deformation bands are mainly located in ferrite/bainite grain boundaries. Furthermore, strain partitioning between ferrite and bainite results in the high-stress concentration in bainite grains. As a result, these “hot zones”, i.e., ferrite grains, ferrite/bainite grain boundaries and bainite grains, experience high strain, strain gradient and stress, respectively, which can be a primary origin of ductile fracture initiation in the 3rd GEN complex phase AHSS. The findings reported in the present investigation would be of great interest in the development of new-generation complex phase automotive steels.

本文研究了第三代(GEN)复相先进高强度钢(AHSS)中各组成相的微观力学性能和变形行为。混合方法是单轴拉伸试验与数字图像相关(DIC)、电子反向散射衍射(EBSD)、原位中子衍射(NED)和晶体塑性有限元法(CPFEM)的综合。结果表明,第 3 代 AHSS 的微观结构呈现出铁素体(46.2%)、贝氏体(36.1%)、马氏体(9.4%)和奥氏体(8.3%)的复相,是开发新一代复相 AHSS 的理想微观结构。重要发现有1)尽管马氏体体积分数较小,但却获得了优异的延展性,同时保持了较高的强度,这可以降低马氏体开裂的倾向;2)成功确定了组成相的宏观应力应变关系和微观硬化特性,这对于预测复相 AHSS 的整体性能非常重要;3)高体积分数贝氏体的存在在诱导铁素体塑性应变局部化方面发挥了关键作用,导致了应力/应变的异质分布。研究表明,明显的应变局部化主要在铁素体晶粒中开始,而变形带主要位于铁素体/贝氏体晶界。此外,铁素体和贝氏体之间的应变分配导致高应力集中在贝氏体晶粒中。因此,这些 "热区",即铁素体晶粒、铁素体/贝氏体晶界和贝氏体晶粒,分别经历了高应变、应变梯度和应力,这可能是第三代 GEN 复相 AHSS 中韧性断裂发生的主要原因。本研究报告的发现对新一代复相汽车钢的开发具有重要意义。


Thin-Walled Structures

Cold-Formed Stainless Steel Beams with Single Web Hole at Elevated Temperatures

Prabowo Andy, Huang Yuner, Young Ben

doi:10.1016/j.tws.2023.111321

高温下的单腹板孔冷弯不锈钢横梁

Steel structures are often used in buildings due to their advantage in weight-to-strength ratio. However, their structural capacity deteriorates in fire as the temperature of the structures rises. Investigation of cold-formed stainless steel (CFSS) structures at elevated temperatures is still limited, especially for rectangular hollow section (RHS) beams having a single web hole in the mid-span (perforated web). Therefore, a numerical investigation was conducted to evaluate the current design provisions to calculate the strength of such beams at elevated temperatures ranging from 22 - 900 °C. A total of 400 specimens of stainless steel grades austenitic (EN 1.4301) and lean duplex (EN 1.4162) were considered. The investigation used finite element analysis (FEA) to simulate the behaviour of RHS beams with perforated web under pure bending. The finite element (FE) model was validated against a series of experimental results available in literature. The comparison between flexural strengths obtained from FEA with design values calculated from the current design rules showed that the design rules are conservative. However, they are not always reliable and safe for RHS beams without and with a perforated web for the two material grades at elevated temperatures. In this study, only the design rules specified by Eurocode 3 are shown to be reliable and safe.

钢结构由于其重量强度比方面的优势,经常被用于建筑物中。然而,在火灾中,随着结构温度的升高,其结构承载能力也会下降。对高温下冷弯型钢(CFSS)结构的研究仍然有限,尤其是对跨中有单腹板孔(穿孔腹板)的矩形空心截面(RHS)梁。因此,我们开展了一项数值研究,以评估当前的设计规定,计算这类梁在 22 - 900 °C 高温下的强度。共考虑了 400 个奥氏体(EN 1.4301)和贫双相(EN 1.4162)不锈钢试样。研究使用有限元分析(FEA)模拟带穿孔腹板的 RHS 梁在纯弯曲下的行为。有限元 (FE) 模型与文献中的一系列实验结果进行了验证。将有限元分析得出的抗弯强度与根据现行设计规则计算得出的设计值进行比较后发现,设计规则是保守的。然而,在高温条件下,对于两种材料等级的无穿孔腹板和有穿孔腹板的 RHS 梁来说,设计规则并不总是可靠和安全的。在本研究中,只有 Eurocode 3 规定的设计规则才是可靠和安全的。


Sectional strength design of a double-skin truss-reinforced composite shear wall

Han Jianhong, Shu Ganping, Qin Ying, Zhou Guangen, Zhou Xiongliang

doi:10.1016/j.tws.2023.111377

双层桁架加固复合剪力墙的截面强度设计

The double-skin truss-reinforced composite shear wall is an innovative element which comprises two steel plates, core concrete, concrete-filled steel tubes (CFSTs), which act as boundary members, and steel truss connectors. Truss connectors decrease the out-of-plane deformation that affects the steel plates, and due to the resultant connection and constraint effects, the truss connectors enhance the bearing capacity of the wall. This paper briefly introduces the quasi-static test of five full-scale rectangular double-skin truss-reinforced composite shear wall specimens. The specimen exhibited shear compression failure with an aspect ratio of 2.0, and flexure shear failure occurred when the aspect ratio exceeded 2.0. Based on the analysis of actual stress state of the steel web and actual working performance of the infilled concrete, the shear strength and flexure strength design formulas of double-skin truss-reinforced composite shear wall were established. Comparison results with 26 specimens demonstrate that the design formulas exhibit remarkable accuracy, as most errors are within 20% and 25%, respectively. Which provide a preliminary sectional strength design proposal for the double-skin truss-reinforced composite shear wall.

双层桁架加固复合剪力墙是一种创新型构件,由两块钢板、核心混凝土、作为边界构件的混凝土填充钢管(CFST)以及钢桁架连接件组成。桁架连接件可减少影响钢板的平面外变形,由于由此产生的连接和约束效应,桁架连接件可提高剪力墙的承载能力。本文简要介绍了五个全尺寸矩形双层桁架加固复合剪力墙试件的准静力试验。试样在长宽比为 2.0 时出现剪切压缩破坏,当长宽比超过 2.0 时出现弯曲剪切破坏。在分析钢腹板实际应力状态和填充混凝土实际工作性能的基础上,建立了双层桁架加固复合剪力墙的抗剪强度和抗弯强度设计公式。与 26 个试件的比较结果表明,设计公式具有显著的准确性,误差大多分别在 20% 和 25% 以内。这为双层桁架加固复合剪力墙提供了初步的截面强度设计建议。


Enhancing performance of hybrid carbon/glass textile-reinforced composites: Theoretical prediction and experimental characterization

Shafiei Ehsan, Zhang Xin

doi:10.1016/j.tws.2023.111375

提高碳/玻璃纤维混合增强复合材料的性能:理论预测和实验表征

Multi-scale analysis is of great interest to calculate the final response of hybrid textile-reinforced carbon/glass epoxy (TRCG) composites based on micromechanical tests and geometrical properties. A novel multi-scale model and experiments are utilized to enhance the performance of TRCG composites. Experiments are conducted on TR glass/epoxy, carbon/epoxy, and 7 hybrid TRCGs. The model integrated viscoplastic-material and nonlinear-geometry properties and damage initiation-propagation mechanisms to address stress–strain curves that incline with experimental data with less than 11 % deviation. The microscopic scanning is utilized to study the fracture mechanisms and delaminated areas of specimens. The tensile curves and delaminated-area of TRCG composites are affected by the local glass/carbon mixed ratio and stacking arrangement. Alternative arrangement, H3:[G/C/G/C]S, provides better mechanical properties and a lower isotropy-mismatch effect and delaminated area compared to H1:[2G/2C]S, and H2:[2C/2G]S, and H4:[C/G/C/G]S. H5:[G/2C/G/C]S with the highest possible properties provides the lowest delaminated-area, because of bridging-glass layers to mitigate brittleness and primary failures of carbon, yet is low enough to restrict premature delamination. H6:[4G/2C/4G] and H7:[2G/2C/G]s with high isotropy-mismatch hustle premature failure and fail to deliver expected performance. The fracture mechanisms of TRCG composites are utilized to propose two 10-layer composites with alternative arrangements, which they are experimented afterwards to study the damage modes. It is concluded that H8:[G/C/G/C/G] laminate has the highest mechanical properties and energy absorption amongst TRCG composites. In which with highest integrity, the delaminated area is limited to the vicinity of fracture zone.

基于微机械测试和几何特性,多尺度分析对于计算混合织物增强碳/玻璃环氧树脂(TRCG)复合材料的最终响应非常重要。我们利用新型多尺度模型和实验来提高 TRCG 复合材料的性能。对 TR 玻璃/环氧树脂、碳/环氧树脂和 7 种混合 TRCG 进行了实验。该模型综合了粘塑性材料和非线性几何特性以及损伤引发-传播机制,以解决应力-应变曲线与实验数据的偏差小于 11% 的问题。利用显微镜扫描研究试样的断裂机制和分层区域。TRCG 复合材料的拉伸曲线和分层面积受局部玻璃/碳混合比和堆叠排列的影响。与 H1:[2G/2C]S、H2:[2C/2G]S 和 H4:[C/G/C/G]S 相比,H3:[G/C/G/C]S 的替代排列具有更好的机械性能、更低的各向同性失配效应和脱层面积。H5:[G/2C/G/C]S具有尽可能高的特性,可提供最小的分层面积,因为桥接玻璃层可减轻碳的脆性和初级失效,同时又足够低以限制过早分层。各向同性不匹配程度较高的 H6:[4G/2C/4G] 和 H7:[2G/2C/G] 会导致过早失效,达不到预期性能。利用 TRCG 复合材料的断裂机理,提出了两种不同排列的 10 层复合材料,并对它们进行了试验,以研究其破坏模式。结果表明,在 TRCG 复合材料中,H8:[G/C/G/C/G] 层板具有最高的机械性能和能量吸收能力。其中,H8:[G/C/G/C/G]具有最高的完整性,分层区域仅限于断裂带附近。


Metal-faced Sandwich composite panels: A Review

Singh Prabhjot, Sheikh Javed, Behera B K

doi:10.1016/j.tws.2023.111376

金属面三明治复合板:综述

This review paper discusses the challenges in improving the mechanical and structural performance of metal-faced sandwich composite panels while reducing weight and cost. It focuses on the core and facesheet structural trends of metal-faced sandwich panels, highlighting innovative design concepts and mechanical performance with respect to failure modes. The paper categorizes recent core geometries used in metal-faced sandwich structures into three types: cellular foam cores, two-dimensional periodic cores, and three-dimensional periodic cores, each with unique characteristics and advantages. The performance of metal sandwich panels with different core structures in response to various mechanical tests is also summarized, including high and low-velocity impact, flexural, and blast and fire resistance. The review emphasizes that the core geometry, facesheet thickness, and core-face interfacial bonding of sandwich composites play a critical role in determining their structural performance and potential applications. Overall, this review paper provides valuable insights into the challenges of improving the mechanical and structural performance of metal-faced sandwich composite panels and highlights the importance of innovative design concepts for achieving optimal performance.

本综述论文讨论了在减轻重量和降低成本的同时提高金属面夹芯复合板的机械和结构性能所面临的挑战。论文重点讨论了金属面夹芯复合板的芯材和面板结构发展趋势,突出强调了创新设计理念和失效模式方面的机械性能。论文将最近用于金属面夹层结构的芯材几何形状分为三种类型:蜂窝泡沫芯材、二维周期芯材和三维周期芯材,每种芯材都具有独特的特点和优势。此外,还总结了采用不同芯材结构的金属夹芯板在各种力学测试中的性能,包括高速和低速冲击、抗弯、抗爆和防火性能。综述强调,夹芯复合材料的芯材几何形状、面板厚度和芯面界面粘接在决定其结构性能和潜在应用方面起着至关重要的作用。总之,这篇综述论文就改善金属面夹芯复合材料板的机械和结构性能所面临的挑战提供了宝贵的见解,并强调了创新设计理念对实现最佳性能的重要性。



来源:复合材料力学仿真Composites FEM
ACTMechanicalDeform断裂复合材料非线性汽车建筑电子UGUM理论材料多尺度试验装配
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【新文速递】2023年11月21日复合材料SCI期刊最新文章

今日更新:Composites Part A: Applied Science and Manufacturing 3 篇,Composites Science and Technology 2 篇Composites Part A: Applied Science and ManufacturingEnhancing mechanical properties and thermal conductivity in polymer bonded explosives by multi-scale surface modification of carbon fibersHe Guansong, Wang Peng, Zhong Ruolei, Li Xin, Yin Huamo, Chen Jie, Liu Shijun, Yang Zhijiandoi:10.1016/j.compositesa.2023.107918通过对碳纤维进行多尺度表面改性,提高聚合物粘合炸药的机械性能和导热性能Poor interfacial interaction and strength largely restrict the overall performance and practical application of carbon fibers (CFs) reinforced composites. The favorable interfacial properties were the key to realize superior mechanical properties in composites. Herein, we reported a novel multi-scale surface modification strategy of CFs to strengthen interfacial properties. Based on chemical oxidation treatment, the surface of CFs was further in situ grafted by a crosslinked high-strength polymer network consisting of aromatic diisocyanate, graphene oxide (GO) and polyethylenen glycol (PEG), which significantly improved the interfacial bonding and mechanical strength of interface layer itself. Benefitting from this multi-scale surface treatment, a high-efficiency mechanical enhancement of polymer bonded explosives (PBX) was achieved. With only 0.3 wt% fiber content, the maximum tensile and compressive strength PBX composites were both significantly improved, which were 63% and 39% higher than those of pure PBX, respectively. Meanwhile, the thermal conductivity was also enhanced, yielding a significant synergistic enhancement effect. The interface failure mechanism of the composite under stress was clarified by the fracture morphology characterization. This study sheds a light for exploring novel surface modification and has the potential application in in high performance polymer composites.界面相互作用和强度差在很大程度上限制了碳纤维(CFs)增强复合材料的整体性能和实际应用。良好的界面性能是实现复合材料优异机械性能的关键。在此,我们报告了一种新型的多尺度碳纤维表面改性策略,以增强界面性能。在化学氧化处理的基础上,进一步在 CF 表面原位接枝由芳香族二异氰酸酯、氧化石墨烯(GO)和聚乙二醇(PEG)组成的交联高强度聚合物网络,从而显著提高了界面层本身的界面结合力和机械强度。得益于这种多尺度表面处理,实现了聚合物结合炸药(PBX)的高效机械增强。在纤维含量仅为 0.3 wt% 的情况下,PBX 复合材料的最大拉伸强度和抗压强度都得到了显著提高,分别比纯 PBX 复合材料高出 63% 和 39%。同时,热导率也得到了提高,产生了明显的协同增强效应。通过断口形貌表征,阐明了复合材料在应力作用下的界面失效机理。这项研究为探索新型表面改性提供了启示,具有在高性能聚合物复合材料中应用的潜力。Shape-memory polyurethane elastomer originated from waste PET plastic and their composites with carbon nanotube for sensitive and stretchable strain sensorZhou Xing, Wang Guosheng, Li Dexiang, Wang Qi, Zhu Keming, Hao Yaya, Xu Yueyang, Li Nengdoi:10.1016/j.compositesa.2023.107920 利用废 PET 塑料制成的形状记忆聚氨酯弹性体及其与碳纳米管的复合材料,用于灵敏且可拉伸的应变传感器Chemical recycling of polyethylene terephthalate (PET) bottles is prospective for reducing waste plastics. The transformation of waste PET into valuable composites in high efficiency still remains a formidable challenge. Here we report the synthesis of polyurethane elastomer (PUE) by using the degraded products from waste PET via one-pot chain extended process. Then, the composites composed of PUE as substrate with carbon nanotubes as fillers are applied in fabricating stretchable strain sensor. The results show that the degraded product was successfully introduced into the polyurethane chains. The PUE chains showed disordered stacking as the degraded product content increased, with the modulus and elongation at break were up to 763.9 %. The composites assembled strain sensors exhibited stable sensing performance and excellent durability after 1000 cycles at 20 % tensile strain. This may supply a path to efficiently recycle waste PET plastic into valuable and functional composites, and even devices.聚对苯二甲酸乙二酯(PET)瓶的化学回收利用在减少废塑料方面前景广阔。如何高效地将废弃 PET 转变为有价值的复合材料仍是一项艰巨的挑战。在此,我们报告了利用废弃 PET 的降解产物,通过一锅扩链工艺合成聚氨酯弹性体(PUE)的过程。然后,以聚氨酯弹性体为基材,碳纳米管为填料组成的复合材料被应用于制造可拉伸应变传感器。结果表明,降解产物被成功引入到聚氨酯链中。随着降解产物含量的增加,聚氨酯链出现了无序堆叠,模量和断裂伸长率高达 763.9%。组装应变传感器的复合材料在 20% 拉伸应变条件下循环使用 1000 次后,显示出稳定的传感性能和出色的耐用性。这为将废弃 PET 塑料有效回收利用为有价值的功能性复合材料甚至设备提供了一条途径。The simultaneously achieved high permittivity and low loss in tri-layer composites via introducing negative permittivity layerSong Xiaoting, Zhang Zidong, Fan Guohua, Liu Yao, Fan Runhuadoi:10.1016/j.compositesa.2023.107921通过引入负介电常数层,在三层复合材料中同时实现高介电常数和低损耗Dielectric composites with excellent power densities have garnered significant attentions in electrical systems and pulsed energy storage. However, the low permittivity and high dielectric loss are greatly limit their applications. Herein, we present a novel approach involving tri-layer composites, where a middle negative-έ layer is sandwiched between outer positive-έ layers. This design aims to realize the balance of comprehensive performances by the interfacial polarization and synergistic effect between positive and negative-έ layers. Amazingly, the composite with content 3-5-3 with the thickness ratio of 1:20:1 shows remarkable permittivity of 679 coupled with a low loss tangent of 0.017 @ 10kHz, which is approximately 141 times higher than PI matrix with 4.8 of permittivity. Remarkably, the composite with content 3-5-3 (1:1:1) exhibited an improved Ud and high η of 1.35 J/cm3 and 94.5%, respectively. This work presents a new class of tri-layer composites with negative-έ layer, whose design method is applicable in high-property dielectric composites.具有出色功率密度的介电复合材料在电气系统和脉冲储能领域备受关注。然而,低介电常数和高介电损耗极大地限制了它们的应用。在此,我们提出了一种涉及三层复合材料的新方法,即在外层正έ层之间夹入中间负έ层。这种设计旨在通过界面极化和正负έ层之间的协同效应实现综合性能的平衡。令人惊奇的是,厚度比为 1:20:1 且含量为 3-5-3 的复合材料显示出 679 的显著介电常数和 0.017 @ 10kHz 的低损耗正切,这比介电常数为 4.8 的 PI 基体高出约 141 倍。值得注意的是,3-5-3(1:1:1)含量的复合材料显示出更高的 Ud 值和更高的η 值,分别为 1.35 J/cm3 和 94.5%。这项研究提出了一种新型负έ层三层复合材料,其设计方法适用于高特性介电复合材料。Composites Science and TechnologyInterfacial reinforcement of carbon fiber composites through a chlorinated aramid nanofiber interphaseMamolo Steven U., Sodano Henry A.doi:10.1016/j.compscitech.2023.110351 通过氯化芳纶纳米纤维间相实现碳纤维复合材料的界面加固Carbon fiber-reinforced polymers (CFRPs) rely on a strong interfacial bond between the reinforcing fibers and polymeric matrix to yield the high strength and toughness expected by a composite material. Poor interfacial strength leads to sub-optimal load transfer and introduces stress concentrations, which can reduce overall performance and result in catastrophic failure. Aramid nanofibers (ANFs) have shown significant promise for interfacial reinforcement in polymeric composite systems due to their high tensile strength, large specific surface area, and abundant polar functional groups. However, due to the chemically inert nature of carbon fibers, ANFs do not readily bond to their surface – thus limiting their application to CFRPs. In this work, we demonstrate that chlorination of ANFs and oxygen plasma treatment of carbon fibers enables the formation of a chlorinated ANF (Cl-ANF) interphase through chemical and physical adsorption using a simple dip-coating process, while fully preserving the tensile strength of the carbon fibers. The Cl-ANF interphase yielded a 79.8 % increase in interfacial shear strength and a 33.7 % increase in short beam strength. By enhancing the interfacial bond between fiber and matrix without degradation of the fiber's tensile strength, this method provides a rapid and reliable process to improve the mechanical properties of CFRP composites.碳纤维增强聚合物(CFRP)依靠增强纤维与聚合物基体之间牢固的界面结合力来实现复合材料所期望的高强度和韧性。界面强度差会导致载荷传递效果不理想,并引起应力集中,从而降低整体性能并导致灾难性故障。芳纶纳米纤维(ANFs)具有拉伸强度高、比表面积大和极性官能团丰富等特点,因此在聚合物复合材料体系中的界面加固方面大有可为。然而,由于碳纤维的化学惰性,ANFs 不易与碳纤维表面结合,因此限制了其在 CFRP 中的应用。在这项工作中,我们证明了对 ANFs 进行氯化处理和对碳纤维进行氧等离子体处理后,可通过简单的浸涂工艺,利用化学和物理吸附作用形成氯化 ANF(Cl-ANF)相,同时完全保持碳纤维的抗拉强度。Cl-ANF 中间相使界面剪切强度提高了 79.8%,短束强度提高了 33.7%。通过增强纤维与基体之间的界面结合力而不降低纤维的抗拉强度,这种方法为提高 CFRP 复合材料的机械性能提供了一种快速可靠的工艺。Optimizing energy storage density of the multi–layer composite of poly(vinylidene fluoride) and nano–Ni plated CaCu3Ti4O12 with an ultralow filling contentGao Liang, Zhang Yuting, Xiao Qianqian, Gao Zhengwu, Wang Xuandoi:10.1016/j.compscitech.2023.110353 优化超低填充物含量的聚偏氟乙烯和纳米镍镀层 CaCu3Ti4O12 多层复合材料的储能密度Surface modification of nanoceramics with high dielectric constant can increase dielectric constant of polymer composites voiding excessive dielectric loss, however, low discharged energy density (Ud) of composites at a low loading limits potential applications in high–energy–storage devices under low electric field. Herein, Ni–plated CaCu3Ti4O12 nanoparticle (CCTO@Ni) is used to improve the electric properties of the poly(vinylidene fluoride) monolayer composites (C/PVDF), and an ultralow loading of 0.5 vol% promotes the largest Ud of 2.53 J/cm3 at 230 MV/m, resulting from MWS interface polarization and Coulomb barrier effect included by CCTO@Ni fillers, which is used to further prepare three kinds of multi–layer structured C/PVDF composites by solution casting layer by layer. Comprehensive testing shows that the PVDF–C/PVDF–PVDF–C/PVDF–PVDF five–layer film (P–C–P–C–P) enhances the dielectric constant and breakdown strength to contribute the maximal Ud of 6.65 J/cm3 at 297.8 MV/m, which is 118% larger than that of pure PVDF. Above excellent characteristics are attributed to the interface polarization of the middle C/PVDF layer and the alleviating and blocking effect of the middle and outer PVDF layers, which are clarified in depth by the finite element simulation and enhanced breakdown model.对具有高介电常数的纳米陶瓷进行表面改性可以提高聚合物复合材料的介电常数,从而避免过多的介电损耗,然而,复合材料在低负载时的低放电能量密度(Ud)限制了其在低电场下高能量存储设备中的潜在应用。在本文中,镀镍的 CaCu3Ti4O12 纳米粒子(CCTO@Ni)被用来改善聚偏氟乙烯单层复合材料(C/PVDF)的电性能,0.5 vol% 的超低负载可使其在 230 MV 下的最大放电能量密度达到 2.53 J/cm3。 CCTO@Ni 填料在 230 MV/m 时产生的 MWS 界面极化和库仑势垒效应,进一步通过逐层溶液浇注制备了三种多层结构的 C/PVDF 复合材料。综合测试结果表明,PVDF-C/PVDF-PVDF-C/PVDF-PVDF 五层薄膜(P-C-P-C-P)提高了介电常数和击穿强度,在 297.8 MV/m 时的最大 Ud 为 6.65 J/cm3,比纯 PVDF 大 118%。上述优异特性归功于中间 C/PVDF 层的界面极化以及中间和外层 PVDF 层的缓解和阻挡作用,有限元模拟和增强击穿模型深入阐明了这一点。来源:复合材料力学仿真Composites FEM

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