今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 5 篇,Composites Science and Technology 3 篇
Analytical homogenization for equivalent in-plane elastic moduli of multi-material honeycombs
Huang Li, Liu Xiang, Liu Xiao, Zhao Xueyi
doi:10.1016/j.compstruct.2023.117586
多材料蜂窝等效面内弹性模量的分析均质化
3D printable multi-material honeycombs have attracted increasing interest recently due to the improved elastic moduli, buckling and energy absorption properties. This paper proposes an analytical homogenization for the equivalent in-plane elastic moduli (EIEM) of multi-material honeycombs. First, the axial and bending stiffness of a cantilever beam consist of three sections made of different materials is formulated. Then based on unit cell method and cantilever beam model, the closed-form expressions of EIEM are proposed by fully considering the deformations of both joints and cell walls with arbitrary stiffness, which are sufficiently general to be applied to hexagonal, auxetic and rectangular multi-material honeycombs and validated very well by numerical simulations and experiments. Furthermore, the effects of geometric and material distribution ratios on EIEM are discussed. The results show that the geometric and material distribution ratios of inclined cell wall have a significant effect on all five EIEM while that of vertical cell wall shows a significant effect on shear modulus but only a slight effect on y- direction elastic moduli. Compared with single-material honeycombs, changing joint stiffness has a significant effect on the equivalent Young’s moduli and shear modulus but a slight effect on Poisson’s ratios.
可三维打印的多材料蜂窝由于具有更好的弹性模量、屈曲和能量吸收特性,最近引起了越来越多的关注。本文提出了一种多材料蜂窝的等效面内弹性模量(EIEM)分析均质化方法。首先,计算由三种不同材料组成的悬臂梁的轴向和弯曲刚度。然后,基于单胞法和悬臂梁模型,充分考虑了具有任意刚度的接缝和胞壁的变形,提出了 EIEM 的闭式表达式,这些表达式具有足够的通用性,可应用于六边形、辅助形和矩形等多种材料蜂窝,并通过数值模拟和实验得到了很好的验证。此外,还讨论了几何和材料分布比对 EIEM 的影响。结果表明,倾斜蜂窝壁的几何形状和材料分布比对五种 EIEM 都有显著影响,而垂直蜂窝壁的几何形状和材料分布比对剪切模量有显著影响,但对 y 方向的弹性模量只有轻微影响。与单一材料蜂窝相比,改变连接刚度对等效杨氏模量和剪切模量有显著影响,但对泊松比影响轻微。
Pin-Loaded Tensile Behavior and Failure Analysis of CF/PEKK Composites under Extreme Temperature
Li Xiaoqi, Kumar Sanjay, Hwang Dong-Wook, Shin Do-Hoon, Kim Yun-Hae
doi:10.1016/j.compositesa.2023.107823
CF/PEKK 复合材料在极端温度下的销装拉伸行为和失效分析
This study investigated pinned-joint bearing strengths and failure behaviors of carbon-fiber-reinforced polyetherketoneketone (CF/PEKK) composites at different temperatures, with varying the width-to-hole diameter (W/D) and edge distance-to-hole diameter (E/D) ratios. Increasing the W/D ratio substantially amplified the pin load capacity, with net tension failure at W/D = 1.5 and bearing failure at W/D ≥ 2, irrespective of temperature. The W/D ratio exerted major influence on the bearing strength, maximum bearing strength was lower at low temperatures (LT; −60℃) (390 MPa) and high temperatures (HT; 200℃) (385 MPa) than that at room temperature (RT; 25℃) (428 MPa). In comparison to RT, a reduction in specimen thickness at bearing area and accelerated localized kink collapse in 0° lamina was observed for LT. The increased ductility of matrix at HT, resulting in fewer matrix cracks. These findings indicate the outstanding bearing load resistance of CF/PEKK composites, supporting their suitability for utilization in high-performance structures.
本研究研究了碳纤维增强聚醚醚酮(CF/PEKK)复合材料在不同温度下的销钉连接承载强度和失效行为,并改变了孔径宽度比(W/D)和孔径边缘距离比(E/D)。无论温度如何,W/D 比的增加都会大大提高针的承载能力,W/D = 1.5 时会出现净拉伸破坏,W/D ≥ 2 时会出现承载破坏。W/D 比对轴承强度有很大影响,低温(LT;-60℃)(390 兆帕)和高温(HT;200℃)(385 兆帕)时的最大轴承强度低于室温(RT;25℃)(428 兆帕)时的最大轴承强度。与室温(RT)相比,在低温(LT)条件下,承载区域的试样厚度减小,0°薄片的局部扭结塌陷加速。HT 时基体的延展性增加,导致基体裂纹减少。这些研究结果表明,CF/PEKK 复合材料具有出色的抗承载能力,因此适合用于高性能结构。
A design methodology of composite scarf repairs using artificial intelligence
Yan Bing, Tong Mingbo, Furtado Carolina, Danzi Federico, Arteiro Albertino, Camanho Pedro P.
doi:10.1016/j.compositesb.2023.111020
使用人工智能的复合材料围巾修补设计方法
Composite Scarf Bonded (CSB) based techniques are highly effective in structural connections and structural repairs. In this article, a preliminary design methodology based on Machine Learning (ML) algorithms trained on databases obtained via a semi-analytical approach is proposed and used to generate the design space for CSB structures under tensile loads. This ML framework introduces the one-hot encoding technology to deal with discrete inputs, such as multiple stacking sequences. Four ML algorithms, Adaptive Boosting, Gradient Boosting Regression, Extreme Gradient Boosting, and Artificial Neural Networks are studied. The best-performing model is then used to generate the damage tolerance-based design space for CSB structures made from fabric and unidirectional prepregs, accounting for material and geometrical uncertainties. Very good representations of the design space and accuracy in structural strength and failure mode are obtained. An optimal scarf angle zone, where laminate and adhesive fail simultaneously, was identified using the proposed framework. This design framework opens new avenues for the selection of material and layup configuration in structural design and enables the fast estimation of the optimal scarf angle range for the preliminary design of CSB structures.
基于复合材料帷幕粘结(CSB)的技术在结构连接和结构修复方面非常有效。本文提出了一种基于机器学习(ML)算法的初步设计方法,该算法在通过半分析方法获得的数据库上经过训练,用于生成拉伸载荷下 CSB 结构的设计空间。该 ML 框架引入了单次编码技术,以处理离散输入,如多个堆叠序列。研究了四种 ML 算法:自适应提升、梯度提升回归、极梯度提升和人工神经网络。然后,使用性能最佳的模型为织物和单向预浸料制成的 CSB 结构生成基于损伤容限的设计空间,并考虑材料和几何不确定性。结果很好地体现了设计空间以及结构强度和失效模式的精确性。利用所提出的框架,确定了层压板和粘合剂同时失效的最佳围边角区域。该设计框架为在结构设计中选择材料和铺层配置开辟了新的途径,并能为 CSB 结构的初步设计快速估算最佳围边角范围。
Ageing effect on the low-velocity impact response of 3D printed continuous fibre reinforced composites
Ferreira L.M., Aranda M.T., Muñoz-Reja M., Coelho C., Távara L.
doi:10.1016/j.compositesb.2023.111031
老化对 3D 打印连续纤维增强复合材料低速冲击响应的影响
This paper aims to analyse the low-velocity impact performance of 3D printed continuous carbon fibre reinforced composites manufactured by fused deposition modelling. Moreover, the effect of ageing on the impact properties and visual damage is studied. This evaluation is crucial for understanding the long-term behaviour and durability of these materials, enabling better design and engineering decisions in various applications where impact resistance is paramount. Low-velocity impact tests were conducted on specimens aged 1, 7, 15 and 30 days. An instrumented drop-weight testing machine was employed for the tests. The dimensions and layup sequence of the composite specimens were designed following the recommendations outlined in the ASTM D7136/D7136M standard for unidirectional composite tapes. Results showed that the initial elastic part slightly reduces with age. In addition, the severity of visual damage in the specimens clearly varied with age. The older specimens present the less visible damage but also the lower impact energy absorption.
本文旨在分析通过熔融沉积模型制造的三维打印连续碳纤维增强复合材料的低速冲击性能。此外,还研究了老化对冲击性能和视觉损伤的影响。这项评估对于了解这些材料的长期行为和耐久性至关重要,有助于在抗冲击性至关重要的各种应用中做出更好的设计和工程决策。对龄期为 1、7、15 和 30 天的试样进行了低速冲击试验。测试使用了一台带仪器的落重测试机。复合材料试样的尺寸和层叠顺序是按照 ASTM D7136/D7136M 单向复合材料带标准中的建议设计的。结果表明,初始弹性部分会随着时间的推移而略微减小。此外,试样视觉损伤的严重程度明显随使用年限而变化。使用年限越长的试样,可见损伤越小,但冲击能量吸收能力也越低。
Lightweight composite gypsum boards with clay mineral and glass fibre for enhanced fire-resistance
Wang Sen, Pancheti Jashnav, Xi Yunfei, Mahendran Mahen
doi:10.1016/j.compositesb.2023.111044
含有粘土矿物和玻璃纤维的轻质复合石膏板可增强防火性能
The current strategy for developing fire-resistant gypsum boards is mainly based on adding porous materials. However, these additives are generally weaker in strength due to higher porosity and are usually produced via energy-intensive processes with relatively higher costs. This paper presents a novel strategy to fabricate lightweight fire-resistant composite gypsum boards through the synergistic coupling of naturally abundant clay mineral - palygorskite (0–30 wt%) and cost-effective glass fibre (0.5 wt%). The bulk density of the obtained boards decreases from 1059 (0 wt% palygorskite addition) to 795 kg/m3 (30 wt% palygorskite). Attributed to the higher initial porosity, reduced shrinkage above 650 °C, and the decomposition of CaSO4 above 925 °C to absorb heat, the ambient side temperature of a composite gypsum board after a 90-min standard fire test is reduced significantly by 150 °C. The new board shows a commendable post-fire strength of 0.15 MPa and fewer cracks than commercial products, which are caused by increased porosity and the bridging effect of glass fibre and sintered palygorskite particles. Through the effective integration of in-situ high-temperature X-ray diffraction, thermal mass loss/heat exchange, and thermal dilatometry, the real-time thermal behaviours of composite gypsum boards are characterised, and the microstructure, physical and mechanical properties and fire resistance are investigated.
目前开发防火石膏板的策略主要是添加多孔材料。然而,由于孔隙率较高,这些添加剂的强度通常较弱,而且通常采用能源密集型工艺生产,成本相对较高。本文提出了一种新的策略,即通过将天然丰富的粘土矿物--叶蜡石(0-30 wt%)和具有成本效益的玻璃纤维(0.5 wt%)协同耦合,制造轻质防火复合石膏板。所获得板材的体积密度从 1059(白云石添加量为 0 wt%)降至 795 kg/m3(白云石添加量为 30 wt%)。由于初始孔隙率较高、650 °C以上收缩率降低以及 CaSO4 在 925 °C以上分解吸热,复合石膏板在 90 分钟标准防火测试后的环境侧温度显著降低了 150 °C。与商业产品相比,新石膏板的火后强度达到 0.15 兆帕,裂缝更少,这是因为孔隙率增加以及玻璃纤维和烧结钙钛矿颗粒的桥接效应所致。通过有效整合原位高温 X 射线衍射、热质量损失/热交换和热膨胀仪,对复合石膏板的实时热行为进行了表征,并对其微观结构、物理和机械性能以及耐火性进行了研究。
A review on advanced cutting tools and technologies for edge trimming of carbon fibre reinforced polymer (CFRP) composites
Geier Norbert, Xu Jinyang, Poór Dániel István, Dege Jan Hendrik, Davim J Paulo
doi:10.1016/j.compositesb.2023.111037
碳纤维增强聚合物 (CFRP) 复合材料切边用先进切割工具和技术综述
Recently, the use of carbon fibre reinforced polymer (CFRP) composites is predominant and will grow further. Although these fibrous composites are often manufactured near net shape, their mechanical machining is often required to meet dimensional tolerances. Considering the difficult-to-cut nature of CFRP composites, the technology planning of edge trimming of CFRPs poses significant challenges and obstacles. Therefore, the main aim of this study is to critically review and discuss challenges, recent expertise and experience gained in the area of edge trimming CFRPs. On the one hand, conventional and advanced edge trimming technologies are reviewed and compared. On the other hand, advanced cutting tools are presented and discussed. Finally, future scope and prospects are highlighted to determine further research scopes in the edge trimming of CFRP composites.
最近,碳纤维增强聚合物(CFRP)复合材料的使用占主导地位,并将进一步增长。尽管这些纤维状复合材料在制造时通常接近净形,但为了满足尺寸公差要求,通常需要对其进行机械加工。考虑到 CFRP 复合材料难以切割的特性,CFRP 边缘修整的技术规划面临着巨大的挑战和障碍。因此,本研究的主要目的是批判性地回顾和讨论 CFRP 边缘修整领域所面临的挑战、最新的专业知识和获得的经验。一方面,对传统和先进的切边技术进行回顾和比较。另一方面,介绍并讨论了先进的切割工具。最后,强调了未来的范围和前景,以确定 CFRP 复合材料切边的进一步研究范围。
Ferroconcrete-inspired construction of wearable composites with a natural leather matrix for excellent neutron-shielding performance
Zhou Jibo, Li Hao, Wen Chun, Wang Yaping, Liao Xuepin, Shi Bi
doi:10.1016/j.compositesb.2023.111043
受铁混凝土启发,用天然皮革基质制造具有优异中子屏蔽性能的可穿戴复合材料
In various sectors, including medical radiotherapy, aerospace exploration, and nuclear energy, the necessity for advanced neutron-shielding materials has escalated. However, these materials often exhibit poor mechanical performance and limited adaptability. To address these shortcomings, this study introduces a novel approach inspired by ferroconcrete construction to develop wearable neutron-shielding materials. This method utilizes the collagen fiber-supported framework present in natural leather, serving as a flexible skeleton, and employs functionalized B4C nanoparticles and paraffin as fillers. The interconnected voids and the unique hierarchical structure of the collagen fibers work synergistically to enable uniform dispersion of B4C nanoparticles, thus enriching the resultant composites with superior neutron-shielding performance. The composite material prepared through this method exhibits a remarkable neutron-shielding effectiveness of 96.93 % and a high linear attenuation coefficient of 17.46 cm−1, outperforming other shielding materials. Additionally, the three-dimensional (3D) woven network of the collagen fiber-supported framework offers impressive mechanical properties, including a tensile strength of 28.59 MPa. This innovative design strategy for creating new wearable neutron-shielding materials paves the way for manufacturing advanced neutron-protective clothing and propels a new structural design with elevated shielding and mechanical performance.
在医疗放射治疗、航空航天探索和核能等各个领域,对先进中子屏蔽材料的需求不断增加。然而,这些材料往往表现出机械性能差、适应性有限等缺点。针对这些不足,本研究从铁混凝土结构中汲取灵感,引入了一种新方法来开发可穿戴的中子屏蔽材料。该方法利用天然皮革中的胶原纤维支撑框架作为柔性骨架,并采用功能化 B4C 纳米粒子和石蜡作为填充物。胶原纤维相互连接的空隙和独特的分层结构协同作用,使 B4C 纳米粒子均匀分散,从而使制备的复合材料具有优异的中子屏蔽性能。通过这种方法制备的复合材料具有显著的中子屏蔽效果(96.93%)和高线性衰减系数(17.46 cm-1),优于其他屏蔽材料。此外,胶原纤维支撑框架的三维(3D)编织网络具有令人印象深刻的机械性能,包括 28.59 兆帕的抗拉强度。这种用于制造新型可穿戴中子屏蔽材料的创新设计策略为制造先进的中子防护服铺平了道路,并推动了具有更高的屏蔽和机械性能的新型结构设计。
Strong and tough glass composites with a partially segmented micro-architecture
Wang Qi, Ding Li, Wang Shuo, Arola Dwayne, An Bingbing, Zhang Dongsheng
doi:10.1016/j.compscitech.2023.110301
具有部分分割微结构的强韧玻璃复合材料
Inspired by the composition of “hard” fin rays and “soft” collagen and the non-segmented and segmented composite structure of fish fins, we propose a partially segmented laminated structure design concept to overcome the brittleness of hard materials. Here, laminated glass composites with a partially segmented micro-architecture are fabricated using a laser engraving approach and a mechanical evaluation of the structure is performed. It is found that the involvement of segmentation enables an incremental cracking mechanism by restraining cracks in segments and a tablet sliding mechanism, thereby producing an unusual combination of strength and toughness. The strength of the partially segmented glass composite is controlled by the depth of segmentation, while the enhancement of toughness is controlled by a superposition of the cracking and sliding mechanisms. The balanced zone involving these mechanisms enables simultaneous improvement of strength and toughness. Additionally, the strength and toughness of partially segmented glass composite can be tuned by varying segment thickness and changing the interlayer materials.
受 "硬 "鳍射线和 "软 "胶原蛋白的组成以及鱼鳍的非分段和分段复合结构的启发,我们提出了一种部分分段层压结构的设计理念,以克服硬质材料的脆性。在此,我们采用激光雕刻方法制造了具有部分分段微结构的层压玻璃复合材料,并对该结构进行了力学评估。研究发现,分段的参与通过限制分段裂纹和平板滑动机制实现了增量开裂机制,从而产生了不同寻常的强度和韧性组合。部分分段玻璃复合材料的强度由分段深度控制,而韧性的增强则由开裂机制和滑动机制的叠加控制。这些机制的平衡区可同时提高强度和韧性。此外,部分分段玻璃复合材料的强度和韧性可以通过改变分段厚度和改变层间材料来调整。
Superelastic and thermal insulating multilayer organic-inorganic hybrid aerogel built from boron nitride nanoribbons and aramid nanofibers
Feng Lei, Wei Peng, Ding Siyuan, Song Qiang, Zhang Jiaxu, Wang Chenhuan, Guo Liyuan, Xu Dongfang, Song Haojie
doi:10.1016/j.compscitech.2023.110277
由氮化硼纳米带和芳纶纳米纤维制成的超弹性和隔热多层有机-无机混合气凝胶
Thermally insulating aramid nanofiber (ANF) aerogels enable a wide range of applications but are limited by their low mechanical elasticity. Efficient design of aerogels’ components and microstructures is crucial yet remains highly challenging for effectively improving the flexibility of ANF aerogels. Here, for the first time, we report the incorporation of boron nitride nanoribbons (BNNRs) into ANF aerogel to form a multilayer BNNR/ANF hybrid aerogel, which is prepared by suspension mixing of BNNRs and ANFs followed by a vacuum-assisted and directional solidification process. Flexible BNNRs with a high aspect ratio are uniformly embedded in the ANF networks, giving the ANF aerogel an extremely high mechanical deformability (up to 60 % compressive strain), capable of retaining its elasticity even after 100 compression cycles or in liquid N2 (−196 °C). Moreover, the introduction of BNNRs does not reduce the thermal insulation capacity of ANF aerogels, while significantly improving their thermal stability and fire resistance. These excellent multifunctionality benefits from the synergistic effect of organic–inorganic components and the multilayer structure of aerogel. This work paves the avenue for developing next-generation elastic and thermal insulating materials with great potential for widespread applications.
绝热芳纶纳米纤维(ANF)气凝胶具有广泛的应用前景,但由于其机械弹性较低而受到限制。气凝胶成分和微结构的高效设计至关重要,但要有效提高芳纶纳米纤维气凝胶的弹性仍极具挑战性。在这里,我们首次报道了在 ANF 气凝胶中加入氮化硼纳米带(BNNR)以形成多层 BNNR/ANF 混合气凝胶。高纵横比的柔性 BNNR 均匀地嵌入 ANF 网络中,使 ANF 气凝胶具有极高的机械变形能力(压缩应变高达 60%),即使在 100 次压缩循环或在液态 N2(-196 °C)中也能保持弹性。此外,引入 BNNRs 不会降低 ANF 气凝胶的隔热能力,同时还能显著提高其热稳定性和耐火性。这些优异的多功能性得益于有机-无机成分的协同效应和气凝胶的多层结构。这项工作为开发下一代弹性和隔热材料铺平了道路,具有广泛应用的巨大潜力。
Lowering the percolation threshold when filling polystyrene with surface-functionalized carbon nanohorns
Sedelnikova Olga V., Baskakova Kseniya I., Bychanok Dzmitry S., Maksimovskiy Eugene A., Bulusheva Lyubov G., Okotrub Alexander V.
doi:10.1016/j.compscitech.2023.110294
用表面功能化碳纳米角填充聚苯乙烯时降低渗流阈值
Carbon nanohorns (CNHs) are highly porous material composed of spherical aggregates of short carbon tubes with closed ends. Given their significant potential for a variety of applications, including electromagnetic shielding, it is important to tune the morphology and surface functionality of CNHs. In this study, CNHs functionalized with –CHx groups were synthesized by arc discharge of a graphite rod with the addition of toluene vapor. The resulting material was used as a filler for polystyrene (PS) composites, whose electromagnetic properties were studied over the frequency range of 1 kHz–4 GHz. Our research showed that functionalization increases the electrostatic association of CNHs, thereby facilitating the formation of conduction paths. As a result, polymer composites containing functionalized CNHs exhibit improved electromagnetic response and lower electrical percolation threshold. The insights gathered from this study provide crucial information on the relation between charge transport and polarization phenomena, the structure of CNHs, their surface state, and their arrangement in the matrix. This information could potentially aid in the further development of this exceptional material.
纳米碳管(CNHs)是一种高多孔材料,由末端封闭的短碳管球形聚集体组成。鉴于其在电磁屏蔽等多种应用中的巨大潜力,调整 CNHs 的形态和表面功能非常重要。在本研究中,通过对石墨棒进行电弧放电并加入甲苯蒸汽,合成了具有 -CHx 基团功能的 CNH。所得材料用作聚苯乙烯(PS)复合材料的填料,研究了其在 1 kHz-4 GHz 频率范围内的电磁特性。我们的研究表明,官能化增加了 CNHs 的静电结合,从而促进了传导路径的形成。因此,含有官能化 CNHs 的聚合物复合材料具有更好的电磁响应和更低的电渗阈值。这项研究提供了有关电荷传输和极化现象、CNHs 结构、表面状态及其在基体中的排列之间关系的重要信息。这些信息可能有助于这种特殊材料的进一步发展。