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【新文速递】2024年3月17日复合材料SCI期刊最新文章

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今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 4 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 1 篇

Composite Structures

The role of printing parameters on the short beam strength of 3D-printed continuous carbon fibre reinforced epoxy-PETG composites

José Humberto S. Almeida, Siddharth Jayaprakash, Kari Kolari, Jukka Kuva, Kirsi Kukko, Jouni Partanen

doi:10.1016/j.compstruct.2024.118034

 

打印参数对 3D 打印连续碳纤维增强环氧-PETG 复合材料短束强度的影响

It is well known that printing parameters strongly affect the mechanical performance of 3D printed parts, especially for recently developed continuous fibre-reinforced composites. This work then explores the printing parameters that mainly affect the mechanical properties of 3D printed composites: i) extruder temperature, ii) print speed, and iii) layer height. The interlaminar strength of the composites exhibits variations in response to changes in these parameters. The carbon fibre-reinforced thermoset filament is printed concomitantly with polyethylene terephthalate glycol (PETG) thermoplastic filament in a single nozzle, characterising a continuous fibre co-extrusion (CFC) process. There is a significant variation in the short beam strength for composites printed with different parameters. The load–displacement curves have a similar pattern, with clear load peaks followed by a plastic zone. Optical micrographs and computed tomography (CT) scans reveal that the microstructure is dependent on the printing parameters. Image analysis elucidates the various mechanisms of void formation. Following the application of a three-way ANOVA and statistical tests to quantify the effects and interactions among variables, the analysis concludes that the extruder temperature has the highest influence, followed by print speed and layer height. When considering all possible interactions between the factors, the interaction between print speed and layer height is the most impactful.

众所周知,打印参数会严重影响三维打印部件的机械性能,特别是对于最近开发的连续纤维增强复合材料。因此,这项研究探索了主要影响三维打印复合材料机械性能的打印参数:i) 挤压机温度;ii) 打印速度;iii) 层高。复合材料的层间强度随这些参数的变化而变化。碳纤维增强热固性长丝与聚对苯二甲酸乙二酯(PETG)热塑性长丝在一个喷嘴中同时打印,这是连续纤维共挤(CFC)工艺的特点。用不同参数印制的复合材料的短梁强度差异很大。载荷-位移曲线具有相似的模式,即明显的载荷峰值之后是塑性区。光学显微照片和计算机断层扫描(CT)显示,微观结构取决于印刷参数。图像分析阐明了空隙形成的各种机制。通过三方方差分析和统计检验来量化变量之间的影响和相互作用,分析得出的结论是挤出机温度的影响最大,其次是打印速度和层高。考虑到各因素之间所有可能的交互作用,打印速度和层高之间的交互作用影响最大。


Composites Part A: Applied Science and Manufacturing

A fatigue test based on inclined loading block concept to benchmark delamination growth considering loading history and R -curve effect

I. Lecinana, J. Renart, L. Carreras, A. Turon, J. Zurbitu, B.H.A.H. Tijs

doi:10.1016/j.compositesa.2024.108128

 

基于倾斜加载块概念的疲劳试验,在考虑加载历史和 R 曲线效应的情况下,对分层增长进行基准测试

The main objective of this paper is to present a delamination benchmark test concept for composite materials that develop non-self-similar delamination in characterization specimens. The non-self-similar delamination is induced by rotating the loading blocks. The simplicity of the test allows for analyzing the loading mode history by concatenating different loading conditions, such as static and fatigue loading, under multiple loading modes. The methodology introduced in this paper can be particularized for any given composite material set and any sequence of loading conditions. To demonstrate the capabilities of the benchmark test, a case study is presented using AS4D/PEKK-FC thermoplastic composite material, which exhibits strong R-curve behavior. A sequence of opening and shear failure modes was applied under static and fatigue loading, providing an experimental data set that is ready to be used as a part of the validation of numerical predictive delamination models. The delamination process was monitored by X-ray radiography, and the final fracture surfaces were analyzed with scanning electron microscopy (SEM), giving a physical insight into the contribution of the fracture mechanisms to the delamination process.

本文的主要目的是针对在表征试样中出现非自相矛盾分层的复合材料提出一种分层基准测试概念。非自相似分层是通过旋转加载块引起的。试验的简易性允许在多种加载模式下通过串联不同的加载条件(如静态和疲劳加载)来分析加载模式历史。本文介绍的方法可针对任何给定的复合材料组和任何加载条件序列进行具体化。为了证明基准测试的能力,本文使用 AS4D/PEKK-FC 热塑性复合材料进行了案例研究,该材料具有很强的 R 曲线行为。在静态和疲劳加载条件下,采用了一系列开裂和剪切失效模式,提供的实验数据集可用于验证数值预测分层模型。分层过程由 X 射线射线照相术进行监测,最终断裂表面由扫描电子显微镜(SEM)进行分析,从而对断裂机制对分层过程的贡献有了物理上的了解。


Experiments and simulations for dynamic yarn pull-out response of Kevlar® fabrics

Frank D. Thomas, Julie Roark, Paul Moy, Subramani Sockalingam, Daniel J. O'Brien, Tusit Weerasooriya

doi:10.1016/j.compositesa.2024.108147

Kevlar® 织物的动态纱线拉出响应实验与模拟

This work presents a novel experimental method for performing dynamic yarn pull-out using a modified tensile split Hopkinson pressure bar. The pull yarn is fixed to a piezoelectric load cell, while the woven fabric specimen is displaced at pull-out velocities ranging from 22 to 32 m/s. Pull-out force, displacement, and energy absorption over time are quantified for commercially available Kevlar® KM2 + woven fabric with pull lengths L = 5 mm and 27 mm in both quasi-static (QS) and dynamic loading. Dynamic peak pull-out force increases over QS by as much as 290–460 % and 170–220 % for L = 5 mm and L = 27 mm, respectively, and overall energy absorption increases by 140–420 % and 40–140 % for L = 5 mm and L = 27 mm, respectively. In QS loading, stick–slip interactions result in forces dropping by approximately 70–80 % between oscillating peaks for L = 5 mm and 30–40 % between peaks for L = 27 mm, and displacements between peaks are typically 1.5 mm, corresponding to two yarn crossings or two spans. However, at dynamic rates, stick–slip stage force drops by 100 % after the first and all subsequent peaks due to the dynamic release of the pull yarn from the fabric, resulting in the pull yarn passing through multiple yarn crossings. To better understand the underlying mechanisms for these observations, finite element simulations of the experiments are performed. Strain rate dependent longitudinal shear stiffness of the yarn is found to significantly affect the dynamic yarn pull-out response and explain the enhanced dynamic yarn pull-out peak force and energy absorption. While the shorter yarn of L = 5 mm experiences a more uniform loading along the entire length, non-uniform loading via progressive uncrimping is observed in the longer yarn of L = 27 mm along the length.

这项研究提出了一种新颖的实验方法,使用改良的拉伸分体式霍普金森压力棒进行动态纱线拉拔。拉伸纱线固定在压电称重传感器上,同时编织物试样以 22 至 32 m/s 的拉伸速度发生位移。在准静态(QS)和动态加载条件下,对拉伸长度 L = 5 毫米和 27 毫米的市售 Kevlar® KM2 + 编织物的拉伸力、位移和随时间变化的能量吸收进行了量化。L = 5 毫米和 L = 27 毫米的动态峰值拉拔力分别比 QS 增加了 290-460 % 和 170-220 %,L = 5 毫米和 L = 27 毫米的整体能量吸收分别增加了 140-420 % 和 40-140 %。在 QS 载荷中,粘滑相互作用导致 L = 5 mm 的振荡峰之间的力下降约 70-80%,L = 27 mm 的振荡峰之间的力下降 30-40%,峰之间的位移通常为 1.5 mm,相当于两个纱线交叉点或两个跨度。然而,在动态速率下,由于牵伸纱线从织物上动态释放,导致牵伸纱线通过多个纱线交叉点,粘滑阶段力在第一个峰值和所有后续峰值之后下降 100%。为了更好地理解这些观测结果的内在机制,我们对实验进行了有限元模拟。结果发现,与应变速率相关的纱线纵向剪切刚度会显著影响动态拉纱响应,并解释了动态拉纱峰值力和能量吸收增强的原因。L = 5 mm 的较短纱线在整个长度上承受的载荷更为均匀,而 L = 27 mm 的较长纱线则在整个长度上通过渐进式非卷曲承受非均匀载荷。


Resin percolation and intimate contact in fast processing of thermoplastic composites

Joseph Kirchhoff, Omar Ghattas, Mehran Tehrani

doi:10.1016/j.compositesa.2024.108145

热塑性复合材料快速加工过程中的树脂渗透和亲密接触

Fusion bonding of thermoplastic composites (TPCs) requires intimate contact before polymer interdiffusion and solidification can establish an interlaminar bond. The lack of such intimate contact results in voids or disbonds. This study showed through cross-sectional imaging and scaling analysis that percolation flow, rather than squeeze flow, of resin through fibers is the dominant mechanism to achieve intimate contact in rapid TPC processes such as automated fiber placement (AFP) and welding. A 1D intimate contact model based on resin percolation, derived from Darcy’s Law, is presented and compared to experiments. While this model proved effective in comparing processing conditions by adeptly capturing trends, it under-predicted resin content in samples processed using AFP with low pressure. The model was extended to high processing rates. In-situ high-speed imaging and ex-situ microscopy revealed void size and morphology based on AFP processing parameters. The results of this study can guide fast processing of thermoplastic composites.

热塑性复合材料(TPC)的熔融粘接需要在聚合物相互扩散和凝固之前进行亲密接触,以建立层间粘接。缺乏这种亲密接触会导致空隙或脱粘。本研究通过横截面成像和缩放分析表明,在自动纤维贴装(AFP)和焊接等快速 TPC 工艺中,树脂通过纤维的渗流而非挤压流是实现亲密接触的主要机制。根据达西定律推导出了基于树脂渗流的一维亲密接触模型,并与实验进行了比较。事实证明,该模型能有效捕捉趋势,从而有效比较加工条件,但它对使用低压 AFP 加工的样品中的树脂含量预测不足。该模型被扩展到高加工率。原位高速成像和原位显微镜显示了基于 AFP 加工参数的空隙大小和形态。该研究结果可为热塑性复合材料的快速加工提供指导。


Preparation of unsaturated self-emulsifying polyester sizing agent for improving interfacial and mechanical properties of carbon fiber/vinyl ester resin composite

Yizhi Geng, Xin Wang, Jiawei Yao, Kangmin Niu, Chuncai Yang

doi:10.1016/j.compositesa.2024.108148

制备用于改善碳纤维/乙烯基酯树脂复合材料界面和机械性能的不饱和自乳化聚酯上浆剂

In order to promote the interfacial adhesion between carbon fiber and vinyl ester matrix, a series of unsaturated self-emulsifying anionic polyester sizing agents were designed. The results indicated that the sizing agents exhibited a uniform particle size distribution at the nanometer level and demonstrated favorable thermal stability below 200 °C. As the content of double bonds of sizing agents increases, the glass transition temperature also increases, and the moisture absorption of sized carbon fiber decreases. The carbon fiber surface becomes smoother after sizing. Moreover, the interlaminar shear strength and interfacial shear strength increased by 18.8 % and 43.4 %, respectively, compared to the commercial carbon fiber. This is mainly due to the unsaturated bonds in the sizing agent react with the free radicals on the surface of the carbon fiber, which enhance the interface bonding strength between the sizing agent and the surface of the carbon fiber and the vinyl ester matrix.

为了促进碳纤维与乙烯基酯基体之间的界面粘合,设计了一系列不饱和自乳化阴离子聚酯上浆剂。结果表明,这些上浆剂的粒度分布均匀,达到纳米级,并在 200 °C 以下表现出良好的热稳定性。随着上浆剂双键含量的增加,玻璃化转变温度也随之升高,上浆碳纤维的吸湿性降低。上浆后的碳纤维表面更加光滑。此外,与商用碳纤维相比,层间剪切强度和界面剪切强度分别提高了 18.8% 和 43.4%。这主要是由于上浆剂中的不饱和键与碳纤维表面的自由基发生反应,从而增强了上浆剂与碳纤维表面和乙烯基酯基体之间的界面结合强度。


Composites Part B: Engineering

“Subconsciousness-triggered” human body defensive strategy: Bi-stability intelligent joint with bionic kirigami structure

Jianyu Zhou, Mei Liu, Sheng Wang, Junshuo Zhang, Mingyang Ni, Shuai Liu, Yu Wang, Huaxia Deng, Bing Liu, Xinglong Gong

doi:10.1016/j.compositesb.2024.111368

 

"下意识触发 "人体防御策略:具有仿生桐神结构的双稳态智能关节

Kirigami structures are increasingly popular in wearable devices due to their exceptional properties. However, their mechanical robustness and anti-impact properties during structural deformation have been overlooked. This study addresses this issue by introducing defects on the surface of composites, mimicking pangolin scales to produce negative Poisson's ratio deformation during tensile strain. Kevlar, conductive shear stiffening elastomer (c-SSE), and PET are combined (Kiri-Kevlar). When subjected to impact, the subconscious rapid response of humans leads to bending arms or curling up, causing Kiri-Kevlar assembled at joints to stretch and undergo structural deformation. The Kiri-Kevlar deformation and high energy dissipation characteristics of c-SSE effectively resist external impact. In summary, a functional-integrated wearable device is developed based on a bionic kirigami structure, realizing efficient anti-impact and providing ideas for a new generation of human-computer interactive intelligent protection devices.

叽里格米结构因其优异的性能在可穿戴设备中越来越受欢迎。然而,它们在结构变形过程中的机械稳健性和抗冲击性能却一直被忽视。本研究通过在复合材料表面引入缺陷,模仿穿山甲的鳞片,在拉伸过程中产生负泊松比变形,从而解决了这一问题。将 Kevlar、导电剪切加固弹性体(c-SSE)和 PET 结合在一起(Kiri-Kevlar)。当受到冲击时,人类下意识的快速反应会导致手臂弯曲或卷曲,从而使装配在关节处的 Kiri-Kevlar 纤维拉伸并发生结构变形。c-SSE 的 Kiri-Kevlar 变形和高能量耗散特性可有效抵御外部冲击。总之,基于仿生叽里格米结构开发的功能集成可穿戴设备,实现了高效抗冲击,为新一代人机交互智能防护设备提供了思路。


Enhancing mechanical and wear performances of magnesium matrix composites using low-cost squid quill ash

Bassiouny Saleh, Reham Fathi, Lu Zhang, Zhiwei Yu, Shenguang Liu, Liguo Zhao

doi:10.1016/j.compositesb.2024.111383

利用低成本乌贼毛灰提高镁基复合材料的机械和耐磨性能

The increasing demand for lightweight, cost-effective aerospace and automotive components with higher performance promotes interest in the use of naturally occurring materials, such as magnesium composites with natural and low-cost reinforcements. This research focuses on stir casting to reinforce magnesium matrix composites with squid quill ash (SQA) particles, aiming to improve their mechanical and wear performances. The results show that the mechanical and wear properties of magnesium matrix composites can be improved significantly by increasing the SQA content. Incorporating 10% SQA reinforcements in AZ91 magnesium alloy leads to a maximum increase in hardness, yield strength and ultimate tensile strength by 32.34%18.86%, and 12.34%, respectively. When compared to the matrix alloy, the wear resistance of the composites reinforced with 5 wt.% and 10 wt.% of SQA particles is improved by 14.05% and 30.81%, respectively. These findings demonstrated the feasibility of using SQA particles in the production of magnesium matrix composites. This not only reduces environmental impact by repurposing SQA, but also provides a practical method for the economical utilization of SQA particles in the fabrication of magnesium matrix composites for aerospace and automotive applications.

对重量轻、成本低、性能高的航空航天和汽车零部件的需求日益增长,这促进了人们对使用天然材料的兴趣,例如使用天然低成本增强材料的镁复合材料。本研究的重点是用搅拌铸造法来增强鱿鱼毛灰(SQA)颗粒的镁基复合材料,以改善其机械和磨损性能。结果表明,镁基复合材料的机械和磨损性能可通过增加 SQA 含量得到显著改善。在 AZ91 镁合金中加入 10%的 SQA 增强材料可使硬度、屈服强度和极限拉伸强度分别最大提高 32.34%18.86% 和 12.34%。与基体合金相比,使用 5 wt.% 和 10 wt.% 的 SQA 颗粒增强的复合材料的耐磨性分别提高了 14.05% 和 30.81%。这些发现证明了在镁基复合材料生产中使用 SQA 颗粒的可行性。这不仅通过对 SQA 的再利用减少了对环境的影响,还为经济地利用 SQA 颗粒制造航空航天和汽车用镁基复合材料提供了一种实用方法。


Composites Science and Technology

Enhancing interface compatibility in high-filled coal gangue/polyethylene composites through silane coupling agent-mediated interface modification

Chao Li, Hongqiang Liao, Hongyu Gao, Fangqin Cheng

doi:10.1016/j.compscitech.2024.110546

 

通过硅烷偶联剂介导的界面改性提高高填充煤矸石/聚乙烯复合材料的界面相容性

This study investigates the profound impact of surface modification using the silane coupling agent KH550 on Coal Gangue (CG)-Polyethylene (PE) composites. The aim was to enhance the properties of composites while addressing waste material accumulation concerns. Comprehensive analyses elucidated the mechanism of interface formation and the subsequent influence on composite properties. Surface modification of CG with KH550 demonstrated pronounced effects on physical, mechanical, and thermal properties of the resulting composites. Notably, the coupling agent facilitated covalent bonding with CG, preventing particle agglomeration and enhancing dispersion stability. The introduction of KH550 contributed to heterogeneous nucleation, augmenting composite crystallinity and interfacial bonding with the resin, thereby improving overall compatibility. Mechanical tests revealed substantial enhancements in tensile and bending strengths with optimal KH550 content. However, excess KH550 led to diminishing returns, highlighting the critical balance required for effective modification. Thermal stability assessments demonstrated improved properties owing to KH550 modification, validating its role in safeguarding the composite matrix from thermal degradation. Microstructural analyses, including SEM, FTIR, DSC, and XRD, provided insights into the interface morphology, chemical composition, crystalline behavior, and structure of the composites. The SEM micrographs elucidated a progressive shift from clear interface boundaries to more homogenously blended states with increasing KH550 content, indicative of enhanced interaction between CG and PE. This comprehensive study demonstrates that KH550 modification offers a strategic approach to optimize CG-PE composites, showcasing potential applications in the automotive and construction industries. Those findings underscore the significance of surface modification techniques in enhancing composite properties and utilizing waste resources efficiently.

本研究探讨了使用硅烷偶联剂 KH550 对煤矸石(CG)-聚乙烯(PE)复合材料进行表面改性的深远影响。目的是提高复合材料的性能,同时解决废料堆积问题。综合分析阐明了界面形成的机理及其对复合材料性能的影响。用 KH550 对 CG 进行表面改性,对所得复合材料的物理、机械和热性能产生了明显的影响。值得注意的是,偶联剂促进了与 CG 的共价键合,防止了颗粒团聚并提高了分散稳定性。KH550 的引入促进了异质成核,提高了复合材料的结晶度以及与树脂的界面结合,从而改善了整体相容性。机械测试表明,KH550 的最佳含量可大幅提高拉伸强度和弯曲强度。然而,过量的 KH550 会导致收益递减,这突出表明了有效改性所需的关键平衡。热稳定性评估表明,KH550改性提高了性能,验证了其在防止复合材料基体热降解方面的作用。包括扫描电镜、傅立叶变换红外光谱、DSC 和 XRD 在内的微观结构分析有助于深入了解复合材料的界面形态、化学成分、结晶行为和结构。扫描电镜显微照片显示,随着 KH550 含量的增加,界面边界逐渐从清晰转变为更均匀的混合状态,这表明 CG 与 PE 之间的相互作用增强。这项综合研究表明,KH550 改性为优化 CG-PE 复合材料提供了一种战略性方法,在汽车和建筑行业具有潜在的应用前景。这些发现强调了表面改性技术在提高复合材料性能和有效利用废弃资源方面的重要意义。



来源:复合材料力学仿真Composites FEM
ACTMechanicalOpticalDeform疲劳断裂复合材料化学光学航空航天汽车建筑电子ADS材料试验
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【新文速递】2024年3月20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 3 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 1 篇Composite StructuresDamage evolution modeling of CFRP/Al single-lap screw type blind riveted joints during realistic installation processFeng Jia-ming, Zhang Jing-dong, Jin Wan-jun, Liao Ri-dongdoi:10.1016/j.compstruct.2024.118023CFRP/Al 单圈螺钉型盲铆接在实际安装过程中的损伤演变模型As studies on the damage behaviors of composites during screw type blind riveting are notably absent, this paper seeks to fill this gap by combining experimental tests and numerical simulation methods. A three-dimensional finite element model was proposed, and the simulation results were obtained and validated by experimental data. The light microscope and scanning electron microscope were used to observe the stress state, axial deformation, damage modes, and damage distribution in two load-bearing regions at the initial contact and after installation. The results demonstrated that the preload showed a four-step “zero -steep rise -decline -steep rise” development during installation. The stress and deformation were concentrated in two circular zones, with the maximum axial stress component and deformation of 321 MPa and 0.046 mm, respectively. In two pressed zones, there were three failure modes, with out-plane matrix crushing being the most severe. In-plane matrix cracking damage is seen at a 45° direction in the first layer, with a damage index of 0.745. In addition, the effect of two geometric parameters of the sleeve on the blind head shape, load-bearing regions, and CFRP damage was investigated. The results would build confidence in reducing CFRP damage and enhancing joint integrity.由于缺乏对复合材料在螺钉型盲铆过程中的损伤行为的研究,本文试图通过结合实验测试和数值模拟方法来填补这一空白。本文提出了一个三维有限元模型,获得了模拟结果,并通过实验数据进行了验证。利用光学显微镜和扫描电子显微镜观察了两个承重区域在初始接触和安装后的应力状态、轴向变形、损伤模式和损伤分布。结果表明,预紧力在安装过程中呈现出 "零--陡升--下降--陡升 "的四级发展过程。应力和变形集中在两个圆形区域,最大轴向应力分量和变形量分别为 321 兆帕和 0.046 毫米。在两个压区中,有三种破坏模式,其中平面外基体破碎最为严重。在第一层的 45° 方向上出现了面内基体开裂破坏,破坏指数为 0.745。此外,还研究了套筒的两个几何参数对盲头形状、承重区域和 CFRP 损伤的影响。这些结果将为减少 CFRP 损坏和提高连接完整性树立信心。Experimental, analytical, and numerical studies of the energy absorption capacity of bi-material lattice structures based on quadrilateral bipyramid unit cellHussain Gharehbaghi, Amin Farrokhabadidoi:10.1016/j.compstruct.2024.118042基于四边形双锥单元的双材料晶格结构能量吸收能力的实验、分析和数值研究The present study investigates the mechanical performance and energy absorption capacity of bi-material 3D lattice structures via experimental, analytical, and numerical approaches. The analytical model has been developed to obtain the effective parameters in energy absorption, such as equivalent elastic modulus and yield stress. Analytical relations based on hyperbolic shear deformation beam theory were extended to calculate the mechanical properties of an extracted unit cell from the lattice structure subjected to applied loads and appropriate boundary conditions. Then, experimental and nonlinear numerical studies have been conducted to analyze the energy absorption properties of the bi-material lattice structure. Quasi-static compression tests were conducted to analyze this lattice structure's mechanical properties and energy absorption capacity. As the numerical study, the elastic-plastic damage behavior was implemented in finite element analyses to examine the nonlinear response of considered structures. The obtained results reveal that the numerical models exhibit an acceptable prediction. According to the results, not only does the use of hybrid structures provide more energy absorption and improve mechanical properties, but also, in comparison to the usual lattice structures fabricated with a single material, the rational combination of two materials makes the bi-material three-dimensional lattice structure to inherit the optimum energy absorption and stiffness.本研究通过实验、分析和数值方法研究了双材料三维晶格结构的机械性能和能量吸收能力。通过建立分析模型,获得了能量吸收的有效参数,如等效弹性模量和屈服应力。基于双曲剪切变形梁理论的分析关系被扩展用于计算从晶格结构中提取的单元格在外加载荷和适当边界条件下的力学性能。然后,通过实验和非线性数值研究分析了双材料晶格结构的能量吸收特性。通过准静态压缩试验分析了该晶格结构的机械性能和能量吸收能力。在数值研究中,在有限元分析中采用了弹塑性损伤行为,以检查所考虑结构的非线性响应。结果表明,数值模型的预测结果是可以接受的。结果表明,使用混合结构不仅能提供更多的能量吸收并改善力学性能,而且与通常使用单一材料制造的晶格结构相比,两种材料的合理组合使双材料三维晶格结构继承了最佳的能量吸收和刚度。Composites Part A: Applied Science and ManufacturingEffect of shear stresses on fibre direction tensile failure using a new simple and reliable test method with thin pliesMeisam Jalalvand, Mohamad Fotouhi, Michael R. Wisnomdoi:10.1016/j.compositesa.2024.108155使用一种新的简单可靠的薄层试验方法,分析剪切应力对纤维方向拉伸破坏的影响A new method of creating in-plane combined tension-shear stress states using only tensile loading is proposed. Thin-ply angle-ply carbon/epoxy laminates are sandwiched between unidirectional glass layers to eliminate any stress concentration around the samples ends and gripping zone. Use of the thin plies successfully suppresses early occurrence of other modes of failure i.e. matrix cracking and free edge delamination, so the first mode of failure is fibre failure in the angle-ply carbon sub-laminate. Compared with other methods of creating combined tension-shear stresses, the proposed technique has a simpler geometry, is significantly easier and cheaper to manufacture and test. Therefore, it provides more repeatable low-scatter experimental results. The obtained experimental results showed that the presence of in-plane shear stresses did not have a significant impact on the tensile fibre-direction failure strain of the tested carbon/epoxy laminate, suggesting that even at high shear stresses, the longitudinal tensile strength of the carbon/epoxy laminate is not significantly reduced.本文提出了一种仅使用拉伸加载来产生平面内拉伸剪切综合应力状态的新方法。薄层角材碳/环氧层压板夹在单向玻璃层之间,以消除样品端部和夹持区周围的应力集中。薄层的使用成功地抑制了其他失效模式(即基体开裂和自由边缘分层)的早期发生,因此第一种失效模式是角层碳子层压板中的纤维失效。与其他产生拉伸-剪切组合应力的方法相比,所提出的技术具有更简单的几何形状,在制造和测试方面明显更容易、更便宜。因此,它能提供可重复性更高的低散射实验结果。实验结果表明,面内剪应力的存在对测试的碳/环氧层压板的拉伸纤维方向破坏应变没有显著影响,这表明即使在高剪应力下,碳/环氧层压板的纵向拉伸强度也不会显著降低。Correlation of the permeability and porosity development of carbon/carbon composites during pyrolysisTania Lavaggi, Faheem Muhammed, Laure Moretti, John W. Gillespie, Suresh G. Advanidoi:10.1016/j.compositesa.2024.108156热解过程中碳/碳复合材料渗透性和孔隙率发展的相关性A cost-effective approach to manufacture Carbon/Carbon composites is to infiltrate carbon fiber preforms with a polymer precursor and pyrolyze it to form the carbon matrix. During pyrolysis, the microstructure changes due to decomposition reactions creating a high degree of porosity consisting of interconnected network of voids and cracks. To densify, the pyrolyzed composite is infiltrated with polymer precursor to fill the porous network. The cycle of pyrolysis followed by infiltration is repeated until the porosity is minimized and the desired density is achieved. The permeability, porosity and viscosity of the polymer govern the infusion pressure and time for the re-infiltration steps. In this work, the permeability of benzoxazine-based Carbon/Carbon composites was measured for different degradation levels with three distinctly different pyrolyzing schedules. The samples were characterized systematically at increasing pyrolyzing temperatures until full conversion of the precursor into carbon matrix was achieved. The porosity of the material was evaluated by X-ray micro-computed tomography and by pycnometry. The through the thickness permeability of the composite was measured via a pulse-decay experiment after each heating step in the pyrolysis cycle. In this experiment pressure decay with time is recorded as air is evacuated from the cavity through the connected pathways of the porous network within the sample. The experimental correlation between the permeability and interconnected porosity of the microstructure is established. It is shown that the pulse-decay test with air effectively characterizes the permeability of the pyrolyzed composite.制造碳/碳复合材料的一种经济有效的方法是在碳纤维预型件中渗入聚合物前体,然后热解形成碳基体。在热解过程中,微观结构会因分解反应而发生变化,形成由空隙和裂缝相互连接的网络组成的高孔隙率。为了增密,热解后的复合材料会渗入聚合物前驱体,以填充多孔网络。先热解后渗透的循环反复进行,直到孔隙率降到最低并达到所需的密度。聚合物的渗透性、孔隙率和粘度决定了再浸润步骤的浸润压力和时间。在这项工作中,我们测量了苯并恶嗪基碳/碳复合材料在三种截然不同的热解过程中的不同降解水平下的渗透性。在热解温度不断升高直至前驱体完全转化为碳基质的过程中,对样品进行了系统表征。材料的孔隙率是通过 X 射线显微计算机断层扫描和比重测定法进行评估的。在热解循环的每个加热步骤之后,通过脉冲衰减实验测量了复合材料的穿透厚度。在该实验中,当空气通过样品内多孔网络的连接通道从空腔中排出时,压力随时间的衰减被记录下来。实验确定了微观结构的渗透性和相互连接的孔隙率之间的相关性。实验结果表明,空气脉冲衰减测试可有效表征热解复合材料的渗透性。Toughing epoxy nanocomposites with Graphite-Nanocellulose layered frameworkDa Li, Peng E, Yibo Shen, Yueshan Li, Fei Cong, Li Liu, Yudong Huang, Zhen Hudoi:10.1016/j.compositesa.2024.108159 具有石墨-纳米纤维素层状框架的韧性环氧纳米复合材料Epoxy nanocomposites hold immense promise for advanced high-performance applications in coatings, adhesives, and fiber-reinforced composite matrices. However, their widespread use is hindered by low fracture toughness, attributed to highly cross-linked network structure. Here, this study presents a synergistic manufacturing strategy combining ultrasonic graphite-nanocellulose assembly and bidirectional freeze casting to fabricate epoxy nanocomposites with remarkable layered architectures. Subsequent infiltration and curing with epoxy prepolymer produce nanocomposites exhibiting a fracture toughness 4.67 times higher than pure epoxy. Both experimental and theoretical analyses demonstrate the nanocomposite's superior crack propagation resistance, attributable to a range of synergistic toughening mechanisms. These include robust interfacial bonding and mechanical interlocking, which arise from fiber pull-out/flake fracture effects, effectively impeding crack growth. Additionally, the distinctive layered architecture promotes tortuous crack pathways, optimizing fracture energy dissipation. This work offers pivotal insights into structure–property relationships, paving the way for the design of next-generation nanocomposites with tailored, superior mechanical performance.环氧纳米复合材料在涂料、粘合剂和纤维增强复合材料基材等先进的高性能应用领域前景广阔。然而,由于高度交联的网络结构导致的低断裂韧性,阻碍了它们的广泛应用。在此,本研究提出了一种协同制造策略,将超声波石墨-纳米纤维素组装和双向冷冻浇注相结合,制造出具有显著分层结构的环氧纳米复合材料。随后与环氧预聚物进行浸润和固化,生产出的纳米复合材料的断裂韧性是纯环氧的 4.67 倍。实验和理论分析表明,纳米复合材料具有优异的抗裂纹扩展能力,这归功于一系列协同增韧机制。其中包括由纤维拔出/片状断裂效应产生的稳固的界面粘合和机械互锁,从而有效地阻止了裂纹的扩展。此外,独特的分层结构促进了曲折的裂纹路径,优化了断裂能量耗散。这项研究为了解结构与性能之间的关系提供了重要依据,为设计具有量身定制的卓越机械性能的下一代纳米复合材料铺平了道路。Composites Part B: EngineeringMelt flow characterization of highly loaded cooper filled poly(acrylonitrile-co-butadiene-co-styrene)Rogério Sakahara, Daniel José da Silva, Shu Hui Wangdoi:10.1016/j.compositesb.2024.111392高负载铜填充聚(丙烯腈-共丁二烯-共苯乙烯)的熔体流动特性分析The knowledge of the rheological behavior of hybrid polymer melts is essential to develop fused deposition modeling (FDM) filaments to print metal and ceramic goods. In this contribution, we performed an in-depth analysis of the morphology and the rheological behavior in the linear elastic domain of poly(acrylonitrile-co-butadiene-co-styrene) (ABS) highly filled with copper microparticles functionalized by bioinspired polydopamine, containing polyethylene waxes (PEW) as lubricant agent. The composite systems have potential applicability in manufacturing FDM filaments for the 3D printing of metallic parts. Small amplitude oscillatory shear (SAOS) tests, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) demonstrate complex relationships among polydopamine coating, filler content, morphology, and rheological properties of the ABS/PEW/Cu system. Furthermore, PEW affects the interface adhesion and shear transmission between the ABS copolymer and the copper filler coated with polydopamine. Also, the polydopamine influences the rheological parameters of the polymer composites, namely retardation and relaxation times, melt flow, and cohesive energy density (Ec).了解混合聚合物熔体的流变行为对于开发用于打印金属和陶瓷制品的熔融沉积成型(FDM)长丝至关重要。在这篇论文中,我们深入分析了聚丙烯腈-共丁二烯-共苯乙烯(ABS)在线性弹性域中的形态和流变行为,其中高度填充了由生物启发聚多巴胺功能化的铜微粒,并含有聚乙烯蜡(PEW)作为润滑剂。这种复合材料系统可用于制造 FDM 长丝,用于 3D 打印金属零件。小振幅振荡剪切(SAOS)测试、扫描电子显微镜(SEM)和傅立叶变换红外光谱(FTIR)显示了 ABS/PEW/Cu 系统的聚多巴胺涂层、填料含量、形态和流变特性之间的复杂关系。此外,PEW 会影响 ABS 共聚物与涂有聚多巴胺的铜填料之间的界面粘附力和剪切传导性。多巴胺还影响聚合物复合材料的流变参数,即延迟和松弛时间、熔体流动和内聚能密度(Ec)。3D printing finite element analysis of continuous fiber reinforced composite materials considering printing pressureBaosheng Liu, Boxiao Dong, Huimin Li, Ruishen Lou, Yi Chendoi:10.1016/j.compositesb.2024.111397考虑打印压力的连续纤维增强复合材料 3D 打印有限元分析Continuous fiber reinforced thermoplastic composite (CFRTC) 3D printing technology, as one of the most remarkable manufacturing techniques, has made significant advancements in various fields, including aerospace and automobile manufacturing. However, there is a dearth of research on simulating the printing process of CFRTC considering printing pressure. This article presents a finite element model that incorporates printing pressure and employs element birth and death technology to simulate the printing process. An in-situ pressure monitoring platform is built to provide real data for simulation. By comparing the simulation results with the experimental results, it is found that the errors of the finite element model simulation results with pressure under different printing parameters are predominantly less than 5 %. Furthermore, the impact of printing temperature and speed on the deformation of the 3D printed CFRTC is analyzed. The deformation of the printed sample is more sensitive to the printing temperature than the printing speed. This study can provide important theoretical guidance for engineering applications.连续纤维增强热塑性复合材料(CFRTC)三维打印技术作为最卓越的制造技术之一,在航空航天和汽车制造等多个领域取得了重大进展。然而,考虑到打印压力而模拟 CFRTC 打印过程的研究却十分匮乏。本文提出了一种包含印刷压力的有限元模型,并采用元素生灭技术来模拟印刷过程。建立了一个现场压力监测平台,为模拟提供真实数据。通过将模拟结果与实验结果进行比较,发现在不同印刷参数下,有限元模型模拟结果与压力的误差主要小于 5%。此外,还分析了打印温度和速度对 3D 打印 CFRTC 变形的影响。与打印速度相比,打印样品的变形对打印温度更为敏感。这项研究可为工程应用提供重要的理论指导。Influence of microvascular structured void content on composites subjected to in-plane shear loadsPhilip Barnett, Jevan Furmanski, Thao Gibson, Dennis Butcher, Jeffery Baurdoi:10.1016/j.compositesb.2024.111390微血管结构空隙含量对承受平面剪切载荷的复合材料的影响Microvascular fiber reinforced composites can be used as multifunctional structures capable of self-healing, thermal regulation, and communication, among others. The inclusion of a small volume of microchannels generally has a minimal impact on the mechanical properties of the composites. In the current work, the in-plane shear properties of microvascular composites containing embedded stainless steel and wall-less microchannels produced through sacrificial material removal were characterized for the first time. Microvascular unidirectional composites were manufactured with precisely located microchannels both aligned with and transverse to the fiber direction, and their in-plane shear properties were tested. Microchannels aligned with the fiber direction were shown to cause a substantial (−7%) decrease in shear strength but had no effect on shear modulus or failure strain. Distortion of the laminate surface around the channels oriented transverse to the fiber axis was observed, resulting in an increase in void content (1–4%), a 9% loss in shear modulus, and a 27% loss in shear strength. The use of a caul plate made the loss in shear strength statistically insignificant, increased the shear modulus by 12–15%, and decreased the shear strain by −25% relative to the baseline composite without microchannels. Digital image correlation showed that the surface strains for transversely oriented samples were interrupted near the microchannels, but post-test x-ray computed tomography and optical microscopy do not show crack redirection. The newfound understanding of the shear response of microvascular composites provides important insights that will enable future engineering designs of multifunctional aerospace structures.微血管纤维增强复合材料可用作具有自我修复、热调节和通信等功能的多功能结构。加入少量微通道通常对复合材料的机械性能影响很小。在目前的研究中,我们首次对含有嵌入式不锈钢微通道和通过牺牲性材料去除产生的无壁微通道的微血管复合材料的面内剪切性能进行了表征。在制造微血管单向复合材料时,精确定位了与纤维方向一致和横向的微通道,并测试了它们的面内剪切性能。结果表明,与纤维方向一致的微通道会导致剪切强度大幅下降(-7%),但对剪切模量或破坏应变没有影响。在纤维轴横向通道周围观察到层压板表面变形,导致空隙含量增加(1-4%),剪切模量损失 9%,剪切强度损失 27%。与没有微通道的基线复合材料相比,使用 caul 板使剪切强度的损失在统计学上不明显,剪切模量增加了 12-15%,剪切应变减少了 -25%。数字图像相关性显示,横向取向样品的表面应变在微通道附近中断,但测试后的 X 射线计算机断层扫描和光学显微镜并未显示裂纹重新定向。对微血管复合材料剪切响应的新认识为未来多功能航空航天结构的工程设计提供了重要启示。Composites Science and TechnologySilica aerogel-PVA dough: A high internal phase composite with superior thermal insulation and gas barrierJianchao Zhang, Yanchun Han, Liying Zhang, Zhaohui Li, Hongsheng Yang, Xiaofang Zhang, Jianming Zhangdoi:10.1016/j.compscitech.2024.110553 二氧化硅气凝胶-PVA团:具有优异隔热性和气体阻隔性的高内相复合材料Silica aerogel (SA) has shown great promise in constructing thermal insulation composites in various forms. However, it is still challenging to disperse a huge amount of SA particles into other matrices for fabricating superior thermal insulation materials or highly filled masterbatch, owing to its high specific surface area and ultra-low density. Herein, inspired by high internal phase emulsion (HIPE), we successfully prepare processable SA/polyvinyl alcohol (PVA) composites (SA-PVA dough) with over 74 vol% dispersed SA, using a PVA aqueous solution as a binder. This is achieved by gradually mixing a large amount of hydrophobic SA filler into a small amount of PVA aqueous solution. The resulting SA-PVA dough exhibits an internal structure resembling that of HIPEs, with hydrophobic SA particles stabilized in the water phase by amphiphilic PVA chains, tightly packed within the thin continuous PVA aqueous phase. Benefiting from such a HIPE structure, the SA-PVA dough can be easily shaped into various forms and exhibits good applicability in further processing. The dried dough inherits the excellent properties of SA, including ultra-low density, superhydrophobicity (water contact angle: 153°), thermal insulation (thermal conductivity: 0.03 W m−1 K−1), and flame resistance. Moreover, the continuous PVA network structure, combined with the nanoscale pore structure of SA, provides the dough with excellent gas barrier properties, greatly expanding the application scope of SA-based composites.二氧化硅气凝胶(SA)在以各种形式制造隔热复合材料方面显示出巨大的潜力。然而,由于二氧化硅气凝胶具有高比表面积和超低密度的特点,要将大量二氧化硅气凝胶颗粒分散到其他基质中以制备优异的隔热材料或高填充母料仍具有挑战性。在此,我们受到高内相乳液(HIPE)的启发,利用 PVA 水溶液作为粘合剂,成功制备出了可加工的 SA/ 聚乙烯醇(PVA)复合材料(SA-PVA 面团),其中 SA 的分散比例超过 74%。这是通过在少量 PVA 水溶液中逐渐混合大量疏水性 SA 填料实现的。由此产生的 SA-PVA 面团显示出类似于 HIPE 的内部结构,疏水性 SA 颗粒被两亲性 PVA 链稳定在水相中,紧密地包裹在薄而连续的 PVA 水相中。得益于这种 HIPE 结构,SA-PVA 面团可以很容易地塑造成各种形状,并在进一步加工中表现出良好的适用性。干燥后的面团继承了 SA 的优良特性,包括超低密度、超疏水性(水接触角:153°)、隔热性(导热系数:0.03 W m-1 K-1)和阻燃性。此外,连续的 PVA 网络结构与 SA 的纳米级孔隙结构相结合,使面团具有优异的气体阻隔性能,从而大大拓宽了基于 SA 的复合材料的应用范围。来源:复合材料力学仿真Composites FEM

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