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
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。
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。
“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。
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。