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【新文速递】2024年5月30日复合材料SCI期刊最新文章

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今日更新:Composite Structures 5 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇

Composite Structures

Does hygrothermal degradation of Mode I fatigue delamination resistance in carbon fibre reinforced polymer laminates depend on the ageing conditions?

Liaojun Yao, Jingchao Wei, Zixian He, Yonglyu He, Stepan V. Lomov, Rene C. Alderliesten

doi:10.1016/j.compstruct.2024.118240

碳纤维增强聚合物层合板抗I型疲劳脱层的湿热退化是否取决于老化条件?

Hygrothermal ageing has detrimental effect of the fatigue delamination growth (FDG) in carbon fibre reinforced polymer laminates, and may increase the crack growth rate by a factor of ∼5. The paper examines, how this degradation for Mode I fatigue delamination is affected by the severity of the ageing conditions. Fatigue delamination tests for R = 0.1 and R = 0.5 are conducted after ageing (1) at 70 °C 85 % relative humidity (RH) and (2) immersion in 70 °C water bath (WB). Paris-type FDG characterisation is derived, in the form, which accounts for the effect of fibre bridging. It is demonstrated that parameters of FDG degradation do not differ for these two types of hygrothermal ageing. The physical reasons for this are examined using dynamic mechanical thermal analysis (DMTA) and fractographic analysis, which revealed similar irreversible degradation of the material near the fibre/matrix interface and in the matrix itself, and the similar damage mechanisms in fatigue delamination. Furthermore, this study can highlight the importance of obeying similitude principles in FDG characterisation, and provide extra information for the ISO standard development for mode I fatigue delamination in unidirectional carbon fibre reinforced polymer composites.

湿热老化对碳纤维增强聚合物层合板的疲劳脱层扩展(FDG)有不利影响,并可能使裂纹扩展速率增加约5倍。本文考察了这种退化的I型疲劳分层是如何受到老化条件的严重程度的影响。(1)在70℃85 %相对湿度(RH)和(2)在70℃水浴(WB)中浸泡后,分别进行R = 0.1和R = 0.5的疲劳分层试验。巴黎型FDG特性推导,在形式中,它说明了光纤桥接的影响。结果表明,两种类型的湿热老化对FDG的降解参数没有影响。使用动态机械热分析(DMTA)和断口分析检查了这一现象的物理原因,揭示了纤维/基体界面附近和基体本身的材料类似的不可逆降解,以及疲劳分层中类似的损伤机制。此外,该研究可以强调在FDG表征中遵循相似原则的重要性,并为单向碳纤维增强聚合物复合材料I型疲劳分层的ISO标准制定提供额外的信息。


Pullout behavior of the steel-FRP composite bar with the anchor head made of the grout-filled steel tube

Gang Xiao, Wei Tan, Peirong Mai, Shiwen Han, Jinping Ou

doi:10.1016/j.compstruct.2024.118242

以灌浆钢管为锚头的钢- frp复合筋的拉拔性能

Steel-fiber reinforced polymer composite bars (SFCBs) offer a viable solution to replace steel bars in concrete structures and mitigate their corrosion issues. However, the inflexibility of SFCBs weakens their bond with concrete. This study addressed this gap by employing a steel tube connected to the end of SFCB using grout as its anchor head. Subsequent pullout tests were conducted on SFCBs with and without anchor heads, exploring variables such as SFCB diameter, anchorage length, anchor-head diameter, concrete-cover thickness, and spiral ratio. Various failure modes were observed, including SFCB rupture, and concrete cracking with and without stirrups. Anchor heads significantly enhanced the bearing capacity and bond stiffness of SFCB specimens, notably reducing splitting forces. Augmenting anchorage length and anchor-head diameter improved the bond stiffness of SFCBs in concrete. The anchor-head diameter should not be less than 2.4 times the SFCB diameter. Furthermore, an increase in concrete-cover thickness or spiral ratio notably heightened the concrete’s resistance to cracking. The contribution ratio of bond force increases with the anchorage length and decreases with the slip, SFCB diameter, and anchor-head diameter. A predictive method for determining concrete-cover thickness and spiral ratio was developed to ensure SFCB pullout specimens steer clear of concrete splitting.

钢纤维增强聚合物复合棒材(sfcb)为混凝土结构中钢筋的替代和腐蚀问题的缓解提供了可行的解决方案。然而,sfcb的不灵活性削弱了它们与混凝土的结合。本研究通过使用一根钢管连接到SFCB的末端,使用浆液作为其锚头来解决这一差距。随后分别对带锚头和不带锚头的SFCB进行了拉拔试验,探索SFCB直径、锚固长度、锚头直径、混凝土覆盖厚度和螺旋比等变量。观察到各种破坏模式,包括SFCB破裂,混凝土开裂有和没有箍筋。锚头显著提高了SFCB试件的承载力和粘结刚度,显著降低了劈裂力。增加锚固长度和锚杆头直径可提高sfcb在混凝土中的粘结刚度。锚头直径应不小于SFCB直径的2.4倍。此外,混凝土覆盖层厚度或螺旋比的增加显著提高了混凝土的抗裂性。黏结力的贡献率随锚固长度的增加而增大,随滑移量、SFCB直径、锚杆头直径的增大而减小。提出了一种确定混凝土覆盖厚度和螺旋比的预测方法,以确保SFCB拉拔试件避免混凝土劈裂。


The influence of temperature and placement rate on wound laminated carbon fibre/PEEK hoop specimens manufactured by in-situ consolidated LATP

Emma Tobin, Aswani Kumar Bandaru, Ronan M. O’Higgins, Paul M. Weaver

doi:10.1016/j.compstruct.2024.118243

温度和放置率对原位固结LATP法制备缠绕碳纤维/PEEK层合箍试样的影响

The effect of laser-assisted automated tape placement (LATP) in-situ consolidation processing parameters on mechanical properties of manufactured laminates is an important consideration. In this study, a combination of placement rates and processing temperatures were assessed to determine their effects on wound laminated hoops for two carbon fibre (CF)/PEEK material systems, one with sized fibres and one without. It was found that these CF/PEEK material systems, while manufactured with the same LATP processing parameters, have different maximum interlaminar shear strengths, void growth characteristics and crystallinity levels. The results indicate that the placement rate has a statistically significant influence on the interlaminar shear strength and sample thickness. It was observed that there is a notable interaction between placement rate and processing temperature for the unsized fibre CF/PEEK system.

激光辅助自动铺带(LATP)原位固结工艺参数对层压板力学性能的影响是一个重要的考虑因素。在这项研究中,评估了放置率和加工温度的组合,以确定它们对两种碳纤维(CF)/PEEK材料系统的缠绕层压箍的影响,一种是有尺寸纤维,另一种是没有尺寸纤维。结果表明,在相同的工艺参数下,CF/PEEK材料体系具有不同的最大层间剪切强度、空隙生长特性和结晶度。结果表明,填充率对层间剪切强度和试样厚度的影响具有统计学意义。研究发现,未上浆的CF/PEEK纤维体系中,放置率与加工温度之间存在显著的交互作用。


Twist design of lattice structure fabricated by powder bed fusion to adjust the energy absorption behavior

Leyao Zhang, Hongshuai Lei, Fei Wang, Panding Wang, Shengyu Duan, Zeang Zhao

doi:10.1016/j.compstruct.2024.118244

粉末床熔合制备晶格结构的捻度设计以调节能量吸收行为

Additive manufactured lattice structures offer great potential for impact resistance applications. They exhibit excellent energy absorption characteristics during the elasto-plastic deformation process, providing protection to internal devices. However, the mechanical response of lattice structures undergoes substantial variations during the deformation process, thereby imposing limitations on their energy absorption behavior. This study introduces a novel twist design to modify the energy absorption behavior of rectangular and hollow cylindrical lattice structures. Powder bed fusion was used to fabricate the twisted lattice structures. The study employed a combination of compressive simulations and experimental investigations to systematically explore the impact of the twist angle on the peak crushing force, energy absorption, and crash load efficiency of the structures. Adjusting the twist angle results in a reduction of the peak crushing force and a transition towards a stable loading profile during the deformation process. Moreover, the crash load efficiency is also reduced. The twist design concept presented in this paper provides insight into designing and optimizing lattice structures for energy absorption applications.

添加剂制造的晶格结构提供了巨大的抗冲击应用潜力。它们在弹塑性变形过程中表现出优异的能量吸收特性,为内部器件提供保护。然而,在变形过程中,晶格结构的力学响应发生了很大的变化,从而限制了它们的能量吸收行为。本文介绍了一种新的扭曲设计来改变矩形和空心圆柱晶格结构的能量吸收行为。采用粉末床熔合法制备了扭曲晶格结构。本研究采用压缩模拟与实验研究相结合的方法,系统探讨扭转角对结构峰值破碎力、能量吸收和碰撞载荷效率的影响。在变形过程中,调整扭转角度可以减少峰值破碎力,并向稳定的加载剖面过渡。此外,碰撞载荷效率也降低了。本文提出的扭曲设计概念为设计和优化能量吸收应用的晶格结构提供了见解。


Micromechanical analysis of fiber-reinforced ceramic matrix composites by a geometrically nonlinear hierarchical quadrature element model

Yingying Lan, Bo Liu

doi:10.1016/j.compstruct.2024.118245

基于几何非线性层次正交元模型的纤维增强陶瓷基复合材料细观力学分析

The stress fields of fiber-reinforced ceramic matrix composites (CMCs) under longitudinal tension are predicted using a non-linear hierarchical quadrature element method (HQEM) in this work. The HQEM combines the differential quadrature method (DQM) with the hierarchical finite element method (HFEM), which is a typical p-version finite element method (FEM). High-order interpolation functions of the HQEM allow accurate evaluation of stress distribution. Fiber, matrix, and interfaces of the CMCs are modeled as linear elastic materials that may have large displacements. The nonlinear HQEM estimation of CMCs stress distributions are validated by comparing with analytical results obtained using classical BHE shear-lag model. Stress distribution in three characteristic stages in the damage evolution process, namely, interface perfectly bonded, interface debonding, and fiber failure are investigated. It is shown that when fiber failure happens, geometric non-linearity must be considered to avoid excessive stress concentration. Furthermore, the stress distribution within three-dimensional cylindrical CMCs cell is studied, which sheds light on the future exploration of three-dimensional CMCs analyses

本文采用非线性层次正交元法(HQEM)预测了纤维增强陶瓷基复合材料在纵向拉伸作用下的应力场。该方法将微分正交法(DQM)与分层有限元法(HFEM)相结合,是一种典型的p型有限元法。高阶插值函数的HQEM允许准确的评估应力分布。cmc的纤维、基体和界面被建模为可能具有大位移的线弹性材料。通过与经典BHE剪切滞后模型的分析结果对比,验证了cmc应力分布的非线性HQEM估计。研究了损伤演化过程中界面完全粘结、界面脱粘和纤维破坏三个特征阶段的应力分布。研究表明,当纤维发生破坏时,必须考虑几何非线性,以避免过度的应力集中。此外,本文还研究了三维圆柱形cmc胞内的应力分布,为进一步探索三维cmc分析提供了理论依据


Composites Part A: Applied Science and Manufacturing

Novel bio-inspired design strategy for balancing of strength/toughness/random defect tolerance of composite

Yansong Shi, Jiawen Zeng, Qiang Zhang, Zuoqi Zhang, Yanan Yuan

doi:10.1016/j.compositesa.2024.108286

复合材料强度/韧性/随机缺陷容忍度平衡的新型仿生设计策略

The shells exhibit exceptional mechanical properties, characterized by significantly higher strength and toughness compared to its constituent materials. This remarkable mechanical behavior is attributed to its microstructure. In the struggle for survival against mantis shrimps, shells are inevitably introduced into random defects, yet these do not compromise its impact resistance properties. This is because the brick–mortar microstructure exhibits excellent defect-insensitivity compared to continuous fiber structures, despite its significantly lower strength. We are considering whether it is feasible to design a new microstructure capable of simultaneously possessing outstanding defect-insensitive properties and high strength/toughness characteristics. Therefore, this paper innovatively proposes a hybrid design strategy for various microstructures. Python script codes were generated to model brick–mortar with varying slenderness ratios including the initial defects. Experiment was also conducted to verify the effective of finite element model. Results shown that Hybrid-1 structure distinguishes itself with the high peak load & damage dissipation energy and excellent defect-insensitive among the designed structures. The defect-insensitive characteristic of damage dissipation energy in Hybrid-2 even surpasses that of the uniform brick-and-mortar structure, while it maintains strength levels nearly equivalent to those of continuous fibers. This hybrid design strategy demonstrates significant potential in achieving a balance among strength, toughness, and tolerance to random defects in microstructures, offering new avenues for biomimetic design in composite materials.

外壳具有优异的机械性能,其特点是与其组成材料相比具有更高的强度和韧性。这种显著的力学性能归因于其微观结构。在与螳螂虾的生存斗争中,炮弹不可避免地引入随机缺陷,但这些并不影响其抗冲击性能。这是因为与连续纤维结构相比,砂浆结构表现出优异的缺陷不敏感性,尽管其强度明显较低。我们正在考虑是否有可能设计一种新的微观结构,能够同时具有出色的缺陷不敏感性能和高强度/韧性特性。因此,本文创新性地提出了一种针对多种微结构的混合设计策略。生成Python脚本代码来模拟具有不同长细比的砂浆,包括初始缺陷。通过实验验证了有限元模型的有效性。结果表明,Hybrid-1结构具有较高的峰值荷载和损伤耗散能以及较好的缺陷不敏感性。Hybrid-2的损伤耗散能的缺陷不敏感特性甚至超过了均匀砂浆结构,而其强度水平几乎与连续纤维相当。这种混合设计策略在实现强度、韧性和对微观结构随机缺陷的容忍度之间的平衡方面显示出巨大的潜力,为复合材料的仿生设计提供了新的途径。


Composites Part B: Engineering

Engineering Digital Light Processing Ceramic Composites for Wide-Range Flexible Sensing Arrays

Dongsu Lee, Dong Hwi Kim, Hyungyong Kim, Hong Min Seung, Hyun-Cheol Song, Miso Kim

doi:10.1016/j.compositesb.2024.111595

 

用于大范围柔性传感阵列的工程数字光处理陶瓷复合材料

Flexible ceramic composites are promising candidates in capacitive pressure sensing applications. However, the fabrication of complex composite structures typically involves costly and time-consuming processes such as lithography or mold utilization. Digital light processing (DLP)-based 3D printing offers a layer-by-layer approach via photopolymerization, facilitating rapid prototyping of various ceramic composite structures in a single-step synthesis process. This study presents the successful implementation of a flexible ceramic composite based on the highly dielectric ceramic BaTiO3 and conductive MWCNT fillers by employing DLP 3D printing to create an hourglass-shaped stress concentration structure, aiming at enhancing flexible capacitive sensing capabilities. Blending commercial flexible resin with 4-acryloyl morpholine monomers yields a photocurable resin formulation with appropriate mechanical flexibility, photocurability, and optimal suspension viscosity suitable for DLP 3D printing. Furthermore, the proposed 3D-printed sensor arrays comprising hourglass-shaped unit cells demonstrate improved linear sensitivity across a broad pressure range owing to efficient stress concentration effects in a symmetric geometry, as corroborated by both finite element methods and experiments. DLP 3D printing, combined with tailored resin formulations and optimized ceramic and conductive filler contents, enables the rapid prototyping of diverse sensor structures with significantly enhanced sensitivity, highlighting the versatility of this approach for a wide range of applications.

柔性陶瓷复合材料在电容式压力传感领域具有广阔的应用前景。然而,复杂复合结构的制造通常涉及昂贵和耗时的过程,如光刻或模具的使用。基于数字光处理(DLP)的3D打印通过光聚合提供了一种逐层方法,促进了在单步合成过程中快速成型各种陶瓷复合结构。本研究成功实现了基于高介电陶瓷BaTiO3和导电MWCNT填料的柔性陶瓷复合材料,采用DLP 3D打印技术创建了沙漏形应力集中结构,旨在增强柔性电容传感能力。将商业柔性树脂与4-丙烯酰啉单体混合,可获得光固化树脂配方,具有适当的机械柔韧性、光固化性和最佳悬浮粘度,适合DLP 3D打印。此外,所提出的由沙漏形单元组成的3d打印传感器阵列,由于对称几何结构中有效的应力集中效应,在宽压力范围内表现出更高的线性灵敏度,这一点得到了有限元方法和实验的证实。DLP 3D打印,结合定制的树脂配方和优化的陶瓷和导电填料内容,使各种传感器结构的快速原型设计具有显着增强的灵敏度,突出了这种方法的多功能性,适用于广泛的应用。


Composites Science and Technology

Strengthening and toughening of hard epoxy vitrimer nanocomposites with interfacial covalent binding and microphase separation

Zhiqiang Chen, Zhen Li, Xubin Wang, Chenyu Jin, Dichao Ning

doi:10.1016/j.compscitech.2024.110684

 

界面共价结合微相分离的硬质环氧树脂纳米复合材料的强化增韧研究

Vitrimers with dynamic covalent bonds combine the merits of thermosets and thermoplastics, opening up new opportunities for science and industry. The attainment of enhanced mechanical performance without compromising dynamic reprocessability poses a significant obstacle to vitrimer materials. Designing vitrimer nanocomposites from interfacial and structural aspects is promising to solve this problem. Herein, strengthening and toughening of hard epoxy vitrimer using nanosilica have been successfully achieved by introducing interfacial covalent binding and microphase separation. Performing interfacial covalent binding between epoxide-modified silica nanoparticles and hard epoxy vitrimer matrix improves interfacial compatibility and nanoparticle dispersion. Controlling the proportion of silica nanoparticles yields two types of microstructures, including a uniformly dispersed material at low nanoparticle loadings and unique microphase separation at high nanoparticle loadings. Particularly, silica reinforcement accompanied with phase separation exhibits a substantial enhancement in Young’s modulus, tensile strength, and fracture toughness while achieving good stretchability. In addition, the silica-epoxy vitrimer nanocomposites preserve excellent reprocessability not inferior to the pristine vitrimer. The resulting nanocomposites show potential applications in bonding, recycling, and shape morphing. The concepts and methodologies presented in this work will enlighten future vitrimer material design.

具有动态共价键的玻璃体结合了热固性和热塑性塑料的优点,为科学和工业开辟了新的机会。在不影响动态再加工性能的情况下获得增强的机械性能是玻璃体材料的一个重大障碍。从界面和结构两方面设计玻璃聚合物纳米复合材料有望解决这一问题。本文通过引入界面共价结合和微相分离,成功实现了纳米二氧化硅对硬质环氧玻璃体的强化增韧。环氧改性二氧化硅纳米颗粒与硬质环氧玻璃体基体之间的界面共价结合改善了界面相容性和纳米颗粒的分散。控制二氧化硅纳米颗粒的比例可以产生两种类型的微观结构,包括低纳米颗粒负载时均匀分散的材料和高纳米颗粒负载时独特的微相分离。特别是,伴随着相分离的二氧化硅增强在杨氏模量、拉伸强度和断裂韧性方面表现出了显著的提高,同时获得了良好的拉伸性。此外,二氧化硅-环氧玻璃体纳米复合材料保持了优异的再加工性能,不逊于原始玻璃体。由此产生的纳米复合材料在键合,回收和形状变形方面具有潜在的应用前景。这项工作中提出的概念和方法将启发未来的玻璃材料设计。


来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveSystemInspire疲劳断裂复合材料碰撞非线性裂纹理论材料仿生控制
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【新文速递】2024年5月12日复合材料SCI期刊最新文章

今日更新:Composite Structures 2 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 4 篇Composite StructuresA novel modeling method to study compressive behaviors of 3D braided composites considering effects of fiber breakage and waviness defectsTao Liu, Danyang Wen, Qingliang Shen, Junhao Liang, Yue Chen, Zhi Fang, Mengyuan Zhang, Siqi Cheng, Yuxuan Gao, Xingzhong Gaodoi:10.1016/j.compstruct.2024.118206一种考虑纤维断裂和波纹缺陷影响的三维编织复合材料压缩特性建模新方法Fiber breakage and waviness defects are two significant and inevitable defects existing in three-dimensional braided composites (3DBCs). This work proposed a new method to create the numerical model containing fiber breakage and waviness defects at the micro-scale level according to experimental characterization results. The experimental tests of 3DBCs with various braiding angles and matrix types are then designed to verify the reliability and adaptability of the model. The results indicate that the fiber breakage and waviness defects both gave rise to an apparent decrease in the axial mechanical properties of the unidirectional and braided composites. The influences of two kinds of defects on 3DBCs are also related to the braiding angles. In addition, the effect of matrix type on the 3DBC is apparent that should not be neglected. The primary reasons of the change of compressive properties of 3DBCs with different matrix types are the variations of the matrix and interfacial properties. The proposed modeling method in this work can be extended for those composites that include a large quantity of fiber breakage and waviness defects.纤维断裂和波状缺陷是三维编织复合材料(3DBC)中不可避免的两种重要缺陷。本研究提出了一种新方法,即根据实验表征结果,在微观尺度上创建包含纤维断裂和波状缺陷的数值模型。然后设计了不同编织角度和基体类型的三维复合材料的实验测试,以验证模型的可靠性和适应性。结果表明,纤维断裂和波状缺陷都会导致单向复合材料和编织复合材料的轴向力学性能明显下降。两种缺陷对 3DBC 的影响还与编织角有关。此外,基体类型对 3DBC 的影响也是不容忽视的。不同基体类型的 3DBC 压缩性能变化的主要原因是基体和界面性能的变化。本文提出的建模方法可扩展用于包含大量纤维断裂和波状缺陷的复合材料。Numerical analysis of L-shaped wrinkling behavior of 3D woven preforms based on a novel hybrid element yarn modelZhi Yang, Lin Shi, Yanan Jiao, Junbo Xie, Xiaoying Cheng, Zhenyu Wu, Qingqing Nidoi:10.1016/j.compstruct.2024.118207基于新型混合单元纱线模型的三维机织预制件l形起皱行为数值分析Numerical simulation is a key means to evaluate the forming performance of 3D woven preforms (3DWPs). However, the macroscopic continuous model of 3DWPs cannot predict the orientation and deformation of yarns, while the microscopic discrete model is unsuitable for large-size samples forming simulation due to computational constraints. A novel mesoscopic hybrid element yarn model is thus proposed to establish a large-size 3D woven virtual yarn preform (VYP) model and the L-shaped virtual forming simulation model. The L-shaped forming experiment of the 3DWP is designed and executed, and the accuracy of the numerical simulation models is verified from three aspects: the mechanical curve, the sample's macroscopic morphology, and the local meso-structure features. Subsequently, the deformation behavior of the yarn structure inside the 3DWP during the L-shaped forming process is analyzed by combining experimental and simulation results. Furthermore, the effects of the L-shaped angle and chamfer radius on the deformation behavior of the 3DWP are studied, which helps guide the structural design of 3DWPs.数值模拟是评价三维编织预制件成形性能的重要手段。然而,3DWPs的宏观连续模型无法预测纱线的取向和变形,而微观离散模型由于计算的限制,不适合大尺寸样品成型模拟。为此,提出了一种新型的细观混合单元纱线模型,建立了大尺寸三维机织虚拟纱线预制件模型和l形虚拟成型仿真模型。设计并实施了3DWP的l形成形实验,并从力学曲线、试样宏观形貌和局部细观结构特征三个方面验证了数值模拟模型的准确性。随后,结合实验和仿真结果,分析了3DWP内纱线结构在l形成形过程中的变形行为。此外,还研究了l形角和倒角半径对3DWP变形行为的影响,有助于指导3DWP的结构设计。Composites Part A: Applied Science and ManufacturingProgressive damage modeling in open hole composite laminates with ultrasound-informed drilling-induced delaminationKirtunia Rahul, Arief Yudhanto, Pruthul Kokkada Ravindranath, David A. Jackdoi:10.1016/j.compositesa.2024.108262超声诱导钻井分层的裸眼复合材料层合板的渐进损伤建模Insertion of fasteners, often used in aerospace and automotive industries, requires drilling that induces non-uniform delamination between lamina of a carbon fiber reinforced plastic (CFRP). Understanding the effect of drilling-induced delamination on the mechanical performance and associated damage mechanisms (progressive damage and failure) is critical to ensure joining integrity. The present work develops an ultrasound testing (UT) method to quantify the drilling-induced delamination at each individual ply interface for CFRP laminates. We then develop a mesoscale finite element (FE) model of an open hole tension specimen by incorporating the UT-obtained drilling-induced delamination at each interface. This delamination is modeled using cohesive zone elements with a bilinear traction-separation law with progressive damage in each ply modeled using the 3D Hashin along with a progressive damage model. Our FE model, with UT-informed delamination, accurately predicts experimental observations of the stress concentration around the hole, damage progression, and open hole tension strength.紧固件的插入通常用于航空航天和汽车工业,需要钻孔,导致碳纤维增强塑料(CFRP)层之间不均匀分层。了解钻井引起的分层对机械性能和相关损伤机制(渐进性损伤和破坏)的影响,对于确保连接完整性至关重要。本工作开发了一种超声检测(UT)方法来量化CFRP层压板在每个单独层界面上的钻孔引起的分层。然后,我们将ut获得的每个界面上的钻井引起的分层结合起来,建立了裸眼拉伸试件的中尺度有限元(FE)模型。这种分层是使用具有双线性牵引-分离律的粘聚区单元来建模的,使用3D Hashin和渐进损伤模型来模拟每层的渐进损伤。我们的有限元模型具有ut信息分层,可以准确预测孔周围应力集中、损伤进展和裸眼抗拉强度的实验观察结果。Composites Part B: EngineeringPioneering the Carbon Fiber Frontier: A Half-Century of Industry Leadership and the Road AheadFumihiko Tanakadoi:10.1016/j.compositesb.2024.111515开拓碳纤维前沿:半个世纪的行业领先地位和未来之路Polyacrylonitrile (PAN)-based carbon fibers have been in full-scale industrialization for more than 50 years, during which time it has grown at an annual rate of 10-20% for half a century, a trend that is expected to continue. Throughout this period, the carbon fiber industry has supported the composites industry through a stable global supply and improved fiber quality. Here, we show PAN-based carbon fibers’ history and future for this 50-year milestone. The industrialization of carbon fiber began in 1959, when Shindo discovered how to stabilize PAN. The later discovery of comonomers based on the Morita-Baylis-Hilman reaction by Morita in 1966 further enabled industrialization. In addition to the innovativeness of this breakthrough, progress was made in converging technologies which intensified competition and encouraged incremental innovation. In recent years, microstructure control has become increasingly precise: down to the molecular level through incremental innovations, with tensile strength reaching 8.0 GPa and named T1200. Evaluating the carbon fibers’ intrinsic strength by the loop method, where evaluation size is reduced to the order of tens of micrometers, shows that the maximum value of T1200 is very high at 18 GPa. This is almost consistent with the value of 19 GPa predicted using molecular dynamics. Even higher strength can be expected by reducing defects. These performance improvements have already contributed toward carbon neutrality in aircraft and wind power generation. PAN-based carbon fibers will continue to be an important material in the future as further performance improvements and increased mass production are realized.聚丙烯腈(PAN)基碳纤维的全面工业化已经有50多年的历史,在此期间,它以每年10-20%的速度增长了半个世纪,预计这一趋势将继续下去。在此期间,碳纤维行业通过稳定的全球供应和提高纤维质量,为复合材料行业提供了支持。在这里,我们展示了pan基碳纤维的历史和未来,这是50年的里程碑。1959年,Shindo公司发现了稳定PAN的方法,从而开始了碳纤维的产业化。后来森田在1966年基于森田-贝利斯-希尔曼反应发现的共聚物进一步推动了工业化。除了这一突破的创新性之外,技术的融合也取得了进展,这加剧了竞争,鼓励了渐进式创新。近年来,微结构控制越来越精确,通过渐进式创新,微结构控制达到分子水平,抗拉强度达到8.0 GPa,命名为T1200。用环法评价碳纤维的固有强度,评价尺寸缩小到几十微米量级,表明T1200在18 GPa时的最大值非常高。这与分子动力学预测的19gpa值基本一致。通过减少缺陷,可以期望更高的强度。这些性能改进已经为飞机和风力发电的碳中和做出了贡献。pan基碳纤维在未来将继续成为一种重要的材料,因为它的性能得到了进一步的改善,并且实现了大规模生产。Thermomechanical fatigue behavior of CF/PEKK composite under low and ultrasonic frequenciesJafar Amraei, Tomasz Rogala, Andrzej Katunin, Aravind Premanand, Grzegorz Kokot, Dominik Wachla, Wacław Kuś, Marcin Bilewicz, Bilal Khatri, Frank Balledoi:10.1016/j.compositesb.2024.111539CF/PEKK复合材料在低频和超声下的热疲劳行为This study aimed to extract the thermomechanical fatigue behavior of a CF/PEKK composite under low and ultrasonic frequency fatigue tests (LFFTs and UFFTs) in the presence of the self-heating effect. Preliminary increasing amplitude tests (IATs) were performed to obtain the minimum load level at which the self-heating is observable. Extracting the fatigue strength from T-σ curves for three mean stress levels resulted in constructing S-N curves for the LFFT regime at different load levels using a shift procedure. However, combining LFFT and UFFT results via S-N curve was impractical, while joining such results through the heat dissipation rate (q) was feasible for various constant amplitude tests and IATs. The derived σ-q curves from combining LFFT and UFFT results and comparing the fracture mechanisms of CF/PEKK composite using fractography would make a step for bridging the transition zone between LFFTs and UFFTs and making the results transferable. The microscopy images obtained from fractography also confirmed the similarities of fatigue fracture mechanisms between LFFTs and UFFTs.本研究旨在提取 CF/PEKK 复合材料在低频和超声波疲劳试验(LFFTs 和 UFFTs)中存在自热效应时的热机械疲劳行为。进行了初步的增大振幅试验(IAT),以获得可观察到自热的最小载荷水平。从三个平均应力水平的 T-σ 曲线中提取疲劳强度后,利用移位程序构建了不同载荷水平下 LFFT 机制的 S-N 曲线。然而,通过 S-N 曲线合并 LFFT 和 UFFT 结果是不切实际的,而通过散热率(q)合并这些结果对于各种恒定振幅试验和 IAT 是可行的。通过结合 LFFT 和 UFFT 结果得出的 σ-q 曲线,并利用断裂显微镜比较 CF/PEKK 复合材料的断裂机理,将为弥合 LFFT 和 UFFT 之间的过渡区并使结果具有可移植性迈出一步。通过断裂显微镜获得的图像也证实了 LFFT 和 UFFT 疲劳断裂机制的相似性。Composites Science and TechnologyEnhanced thermal conductivity and mechanical property via improvement of hydrogen bonding between hexagonal boron nitride and aramid copolymerHwakyung Jeong, Jaegeun Lyu, Howon Choi, Min Woo Kim, Juyoung Kim, Hyeonsuk Yoo, Yongjin Lee, Ji Ho Youk, Han Gi Chaedoi:10.1016/j.compscitech.2024.110652 通过改善六方氮化硼与芳纶共聚物之间的氢键,提高了其导热性和力学性能This study focuses on enhancing thermal properties of aramid copolymer nanocomposites by integrating hexagonal boron nitride (hBN). Pristine hBN (P-hBN) is first subjected to oxidative heat treatment at 900 °C, producing thermally treated hBN (T-hBN), which significantly improves thermal conductivity while also increasing the tensile properties of composites. The study further explores the effect of different diamine co-monomers, 3,4’- and 4,4’-oxydianiline (ODA), on the nanocomposite properties. Both types of ODA-based composite films show improvement in various properties containing T-hBN. With 20 wt% of T-hBN, the 3,4'-ODA and 4,4'-ODA-based films exhibit 33.2% and 290% increase in tensile strength and thermal conductivity, respectively. The functionalization of hBN by heat treatment enhances the interaction between aramid copolymer and hBN and prevents the aggregation of hBN. The rough interface was shown in fractured images for films with T-hBN, suggesting that the composite films with T-hBN withstand higher external forces. In addition, it was observed that T-hBN exhibits better dispersion compared to P-hBN. This is supported by molecular dynamics (MD) simulation, and, in addition, it also provides the underlying mechanism for the property differences between both types of co-monomers.本文主要研究了通过集成六方氮化硼(hBN)来提高芳纶共聚物纳米复合材料的热性能。原始hBN (P-hBN)首先在900℃下进行氧化热处理,得到热处理后的hBN (T-hBN),显著改善了复合材料的导热性,同时也提高了复合材料的拉伸性能。本研究进一步探讨了不同的二胺共单体3,4 ' -和4,4 ' -氧化二胺(ODA)对纳米复合材料性能的影响。两种类型的oda基复合膜均表现出含有T-hBN的各种性能的改善。当T-hBN添加量为20%时,3,4'-ODA和4,4'-ODA基薄膜的抗拉强度和导热系数分别提高了33.2%和290%。热处理使hBN功能化,增强了芳纶共聚物与hBN的相互作用,防止了hBN的聚集。含T-hBN的复合膜在断裂图像中显示出粗糙的界面,表明含T-hBN的复合膜承受更高的外力。此外,与P-hBN相比,T-hBN具有更好的分散性。这得到了分子动力学(MD)模拟的支持,此外,它还提供了两种类型的共聚单体之间性能差异的潜在机制。Enhanced interfacial, mechanical, and anti-hygrothermal properties of carbon fiber/cyanate ester composites with the catalytic sizing agents of titanium epoxyXu Peng, Yushan Wu, Yifan Li, Yu Xiang, Hantian Lu, Zhengli Hua, Faxiang Qin, Hua-Xin Pengdoi:10.1016/j.compscitech.2024.110658 环氧钛助剂增强了碳纤维/氰酸酯复合材料的界面性能、力学性能和抗湿热性能The mechanical properties of composites are closely related to the interfacial behavior, especially under the hygrothermal circumstance. A catalytic sizing agent of titanium epoxy is designed to enhance interfacial, mechanical, and anti-hygrothermal properties of high modulus carbon fiber (HMCF)/cyanate ester composites simultaneously. The mechanisms of interface enhancement and low hygroscopicity of composites are investigated. The titanium epoxy is synthesized and its catalytic effect on the curing of cyanate ester is proved. The interfacial properties of HMCF composites with catalytic sizing agents are improved to 95.5 MPa, which is attributed to the interphase with high crosslinking density and sufficient triazine rings and oxazolidinone structure due to preferential curing induced by interfacial catalysis, stimulating the smooth transition of interphase modulus. Further, the formed interphase exhibits few interface defects and low content of hydroxyl groups, which changes the moisture diffusion path and reduces saturated water absorption of composites to only 0.36%, resulting in the release of interfacial wet stress concentration and high retention of mechanical properties in hygrothermal environment. The resultant composites with high stiffness, excellent temperature resistance, superior dimensional stability and low moisture absorption are expected to be applied to high-orbit space, aerospace, precision instruments.复合材料的力学性能与界面行为密切相关,特别是在湿热环境下。为了同时提高高模量碳纤维(HMCF)/氰酸酯复合材料的界面性能、力学性能和抗湿热性能,设计了一种环氧钛催化施胶剂。研究了复合材料界面增强和低吸湿性的机理。合成了钛环氧树脂,并验证了其对氰酸酯固化的催化作用。添加了催化施胶剂的HMCF复合材料的界面性能提高到95.5 MPa,这是由于界面催化诱导的优先固化使界面相具有较高的交联密度和充足的三嗪环和恶唑烷酮结构,刺 激了界面相模量的平稳过渡。形成的界面相界面缺陷少,羟基含量低,改变了水分扩散路径,使复合材料的饱和吸水率降至0.36%,从而释放界面湿应力集中,在湿热环境下保持较高的力学性能。该复合材料具有高刚度、优异的耐温性、优越的尺寸稳定性和低吸湿性,有望应用于高轨道空间、航空航天、精密仪器等领域。Capillarity-assisted assembly of composite fibers to enable highly conductive fabrics for electromagnetic interference shieldingYing Lu, Jiali Xu, Yutong Liu, Jingling Ban, Xiufang Li, Mufang Li, Yang Zhou, Dong Wang, Longhai Piaodoi:10.1016/j.compscitech.2024.110659 复合纤维的毛细管辅助组装,使高导电织物能够屏蔽电磁干扰Poor adhesion between silver nanomaterials and substrates seriously restricts the development of electronic composite devices. In this work, flexible and conductive silver nanowires/fibroin/ degummed silk (AgNWs/fibroin/dSF) composite fibers with high adhesion and conductivity via capillarity-assisted assembly for electromagnetic interference (EMI) shielding are designed and fabricated by a facile and scalable all-solution dip-coating method. The nanocomposite fiber possesses high conductivity with a resistance of 8.8 Ω/cm at a low AgNWs/fibroin loading of 19.3 wt%. The assistance of the capillary force in the fiber highly increases the mass of deposited AgNWs. Furthermore, the AgNWs show high adhesion on the fibers in the tape-peel test. The enhanced deposition factors and mechanisms are detailly investigated. Moreover, the composite fibers are further woven into a soft and flexible fabric. The composite fabric shows an absorption-dominated EMI shielding performance with an efficient shielding effectiveness of 38 dB. The capillarity-assisted assembly is an attractive procedure for constructing high-conductive and uniform coatings for a wide application.银纳米材料与衬底的粘附性差严重制约了电子复合器件的发展。在这项工作中,通过毛细管辅助组装,设计和制造了具有高附附性和导电性的柔性导电银纳米线/丝素/脱胶丝(AgNWs/丝素/dSF)复合纤维,用于电磁干扰(EMI)屏蔽。该纳米复合纤维在AgNWs/丝素负载为19.3 wt%时具有8.8 Ω/cm的高电导率。纤维中毛细力的辅助作用极大地增加了沉积的AgNWs质量。此外,在胶带剥离测试中,AgNWs在纤维上显示出高附着力。详细探讨了增强沉积的因素和机理。此外,复合纤维进一步编织成柔软而有弹性的织物。复合材料具有以吸收为主的电磁干扰屏蔽性能,屏蔽效率为38 dB。毛细管辅助组装是一种具有广泛应用价值的高导电性、均匀涂层的制备方法。Enhanced thermoelectric properties of carbon nanotubes/polyaniline fibers through engineering doping level and orientationChun Zhang, Yalong Liu, Hui Li, Siqi Liu, Pengcheng Li, Han Zhang, Chaobin Hedoi:10.1016/j.compscitech.2024.110660 通过工程掺杂水平和取向增强碳纳米管/聚苯胺纤维的热电性能The rapid progress of miniaturized wearable electronics has put forward great requirements for organic fiber-based thermoelectric (TE) generators. Despite polyaniline (PANI) exhibits many outstanding attributes such as facile synthesis and low cost, as well as good environmental and thermal stability, only a few PANI-based fibers were fabricated and their TE efficiency needs to be further improved. In this work, the TE performance of wet-spun carbon nanotubes (CNTs)/PANI fibers was improved by synergistic engineering doping level of PANI and orientation of the fibers. The doping degree was optimized by varying coagulation baths, bath durations, and dopant loadings in the spinning solution, followed by fixing process during air drying to decrease shrinkage and enhance orientation of the fiber. Hexane coagulated CNTs/PANI fibers exhibited a higher doping degree of PANI compared to that of acetone and ethyl acetate, resulting in a maximum TE power factor of 77.4 μW m-1K-2 for 71 wt% CNTs/PANI fibers at PANI/dopant molar ratio of 2:1.25. Further fixing process induced a more oriented structure along the fibers, facilitating carrier transport and contributing to a significantly increased conductivity of 2155 S cm-1. Consequently, the CNTs/PANI fibers reached an optimal power factor of 91.8 μW m-1K-2. With outstanding TE performance and mechanical properties, the resultant fibers were assembled to fabricate a flexible TE generator, which generated a high output power of 2.5 nW with a temperature gradient of 10 K. These results demonstrate the potential of high-performance CNTs/PANI fibers to harvest body heat for the power supply of the wearable electronics.小型化可穿戴电子产品的快速发展对有机纤维热电发生器提出了很高的要求。尽管聚苯胺(PANI)具有合成简单、成本低、环境和热稳定性好的优点,但目前制备的聚苯胺基纤维数量较少,其TE效率有待进一步提高。本研究通过聚苯胺的工程掺杂水平和纤维取向的协同作用,提高了湿纺碳纳米管/聚苯胺纤维的TE性能。通过改变混凝浴、浴浴时间和纺丝液中掺杂量来优化掺杂程度,然后在风干过程中进行固定工艺,以减少收缩,增强纤维的取向性。与丙酮和乙酸乙酯相比,己烷混凝的CNTs/PANI纤维具有更高的PANI掺杂度,当PANI/掺杂摩尔比为2:25时,71% wt%的CNTs/PANI纤维的最大TE功率因数为77.4 μW m-1K-2。进一步的固定过程诱导了沿纤维方向更定向的结构,促进了载流子的运输,并显著提高了2155 S cm-1的电导率。因此,CNTs/PANI纤维的最佳功率因数为91.8 μW m-1K-2。合成的纤维具有优异的TE性能和机械性能,组装成柔性TE发生器,产生2.5 nW的高输出功率,温度梯度为10 K。这些结果表明,高性能碳纳米管/聚苯胺纤维有潜力收集人体热量,为可穿戴电子设备供电。来源:复合材料力学仿真Composites FEM

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