今日更新:Composite Structures 2 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Crashworthiness investigation on a Carbon Fiber Reinforced Plastic solar vehicle
Alessandro Papavassiliou, Ana Pavlovic, Giangiacomo Minak
doi:10.1016/j.compstruct.2024.118147
碳纤维增强塑料太阳能汽车的耐撞性研究
This article presents a research study involving different simulations of crash tests by means of the finite element explicit dynamic software Ansys LS-Dyna to determine the roadworthiness of a fully composite chassis lightweight solar vehicle and its conformity to the World Solar Challenge (WSC) regulations. Furthermore, the paper describes the results of crash test simulations in conditions comparable with those of the standard homologation test, with an initial velocity of 15.5 m/s against a rigid barrier considering overlaps of 50% and 100%. The velocity measured at the base of the seat was later used in a sled test with a dummy to calculate the Head Injury Criterion (HIC), a number proportional to the probability of head injury caused by the impact. The values remained within the threshold of acceptability with overlap at 50% but exceeded the limit with the 100% overlap. With no load limiter implemented in the model, the seatbelt caused contact forces with the chest up to 14 kN against 6 kN of the typical load limiter used in road cars to limit damage to ribs and internal organs. Finally, the possibility of improving the front crash box was investigated by changing the crash box’s planar sandwich structure with corrugated ones and layup without foam between the carbon layers. Various values of semi-amplitudes (A) of the sinusoidal profile have been tested. With a value of A of 6 mm, the capacity to absorb energy from an impact at 9 m/s was close to the original configuration.
本文采用有限元显式动力软件Ansys LS-Dyna进行了不同碰撞试验模拟研究,以确定全复合材料底盘轻型太阳能汽车的路适性及其符合世界太阳能挑战赛(WSC)规则。此外,本文还描述了在考虑50%和100%重叠的情况下,以15.5 m/s的初始速度撞击刚性屏障的碰撞试验模拟结果,与标准一致性试验的条件相当。在座椅底部测量的速度随后用于假人的雪橇试验,以计算头部损伤标准(HIC),该标准与撞击造成头部损伤的概率成正比。当重叠为50%时,这些值仍在可接受阈值范围内,但当重叠为100%时,这些值超过了可接受阈值。在模型中没有实施载荷限制器的情况下,安全带与胸部的接触力高达14千牛,而公路汽车中使用的典型载荷限制器为6千牛,以限制肋骨和内脏的损伤。最后,研究了将前碰撞箱的平面夹层结构改为波纹夹层结构和碳层间无泡沫叠层的可能性。对正弦剖面的各种半振幅(A)值进行了测试。当a值为6 mm时,吸收9 m/s冲击能量的能力接近于原始配置。
Microstructure generation and full-field multi-scale analyses for short fiber reinforced thermoplastics: Application to PA66GF composites
Francis Praud, Konrad Schneider, George Chatzigeorgiou, Fodil Meraghni
doi:10.1016/j.compstruct.2024.118175
短纤维增强热塑性塑料的微观结构生成及现场多尺度分析:在PA66GF复合材料中的应用
Short Fiber Reinfored Thermoplastics (SFRTs) like PA66GF composites are highly heterogeneous materials with a rather complex microstructure such that the characterization and the prediction of their mechanical behavior remain quite challenging. So far, most of the research efforts have employed phenomenologigal and mean-field multi-scale models to deal with SFRTs. The present contribution rather focuses on a full-field multi-scale approach that incorporates advanced techniques in terms of microstructural representation and material modeling, allowing a deep insight of the dominating deformation mechanisms occurring in PA66GF composites. The proposed approach is based on an automatic periodic mesh generation algorithm for matrix-inclusion Representative Volume Elements (RVE) with randomly positioned fibers that follow a given Orientation Distribution Function (ODF). At the microscopic scale, while the fibers are assumed to be elastic, the behavior of the thermoplastic matrix is described by a phenomenological multi-mechanism constitutive model accounting for viscoelasticity, viscoplasticity and ductile damage. It results an advanced multi-scale model that enables to visualize the local deformation and degradation mechanisms occurring at the microscopic scale while simultaneously analyzing their influence on the macroscopic response of the composite upon monotonic, persistent and cyclic loading. The potential of the proposed approach is further evaluated by comparing the predicted responses against experimental data.
短纤维增强热塑性塑料(SFRTs),如PA66GF复合材料是高度非均相材料,具有相当复杂的微观结构,因此其力学行为的表征和预测仍然是相当具有挑战性的。到目前为止,大多数研究都是采用现象学和平均场多尺度模型来处理sfrt。目前的贡献主要集中在一个全领域的多尺度方法,该方法结合了微观结构表示和材料建模方面的先进技术,从而深入了解PA66GF复合材料中发生的主要变形机制。该方法是基于矩阵包含代表性体积元(RVE)的自动周期性网格生成算法,其中随机定位的纤维遵循给定的方向分布函数(ODF)。在微观尺度上,假设纤维是弹性的,热塑性基体的行为由考虑粘弹性、粘塑性和延性损伤的现象学多机制本构模型来描述。建立了一种先进的多尺度模型,可以在微观尺度上可视化局部变形和降解机制,同时分析它们对复合材料在单调、持久和循环加载下的宏观响应的影响。通过将预测响应与实验数据进行比较,进一步评估了所提出方法的潜力。
Japanese washi-paper-based green composites: Fabrication, mechanical characterization, and evaluation of biodegradability
Lovisa Rova, Alia Gallet-Pandellé, Zhenjin Wang, Hiroki Kurita, Fumio Narita
doi:10.1016/j.compositesa.2024.108261
日本纸基绿色复合材料:制造、机械特性和生物降解性评价
In this study, sheets of Japanese washi-paper were layered and hot pressed with films of poly(butylene succinate) (PBS) in order to produce a fiber-reinforced composite material that can be biodegraded. Using traditional Japanese washi-paper, a thin yet remarkably strong green composite with excellent biodegradability was produced, proving the potential of washi-paper as an attractive reinforcer in green composites. The composite was biodegraded in compost, and the ultimate aerobic biodegradability as well as weight loss and loss of mechanical properties during biodegradation was evaluated. Specimens fabricated from three layers of washi-paper and two layers of PBS film had remarkable mechanical properties, including an ultimate tensile strength of 59.85 MPa. Scanning electron microscopy was used to study the cross-sectional structure of the material, which showed that the hollow washi-paper provides a structure for the polymer to settle into and surround the cellulose fibers. The large contact area between the cellulose fibers and the PBS caused a large internal friction which prevented failure by fiber pull-out, dramatically increasing the strength compared to neat washi-paper and neat PBS. Concerning biodegradability, the material reached 82 % biodegradation after 35 days. During biodegradation, the composite lost its mechanical properties fast, and was extremely fragile after 2 weeks inside the compost. After 6 weeks, the biodegradation had progressed so far that it was difficult to distinguish the material inside the compost. Due to its fast biodegradation and good mechanical strength, the washi-based composite material is potentially used in packaging, furniture, and agricultural applications such as mulch film.
在这项研究中,将日本的洗衣纸分层并与聚丁二酸丁二烯(PBS)薄膜热压,以生产一种可生物降解的纤维增强复合材料。以日本传统的废纸为原料,制备了一种薄而强且具有良好生物降解性的绿色复合材料,证明了废纸作为绿色复合材料增强剂的潜力。在堆肥中对复合材料进行生物降解,并对其最终的好氧生物降解性以及生物降解过程中的重量损失和机械性能损失进行了评价。三层水洗纸和两层PBS膜制备的试样具有显著的力学性能,其极限抗拉强度为59.85 MPa。利用扫描电子显微镜对材料的横截面结构进行了研究,结果表明,中空的卫生纸为聚合物进入并包围纤维素纤维提供了一种结构。纤维素纤维与PBS之间的大接触面积产生了很大的内摩擦,防止了纤维被拉出而破坏,与干净的卫生纸和干净的PBS相比,强度大大提高。在生物降解性方面,材料在35 天后达到82% %的生物降解。在生物降解过程中,复合材料的力学性能迅速丧失,在堆肥中放置2 周后极易破碎。6 周后,生物降解已经进展到难以区分堆肥内部的物质。由于其快速的生物降解和良好的机械强度,水洗基复合材料有潜力用于包装、家具和农业应用,如地膜。
Rational design and controlled synthesis of metal-organic frameworks to meet the needs of electrochemical sensors with different sensing characteristics: an overview
Jingcheng Huang, Haowei Dong, Lingjun Geng, Rui Xu, Mengyue Liu, Zhen Guo, Jiashuai Sun, Xia Sun, Yemin Guo
doi:10.1016/j.compositesb.2024.111536
合理设计和可控合成满足不同传感特性电化学传感器需求的金属有机骨架综述
It is known that porous structure of materials offers opportunities for the creation of a new range of materials with precise functions. Metal-organic frameworks (MOFs) are ordered porous materials formed by self-assembly of metal nodes and organic ligands. The study found that MOFs are ideal sensing materials. Recently, increasing attention has focused on developing MOFs-based electrochemical (EC) sensors due to their adjusted pore sizes , large surface area, and excellent physical/chemical stability. Various pure MOFs with distinct structures and functions can be synthesized by selecting different metal centers and organic ligands, the MOFs family has been further extended through the exploration of MOFs-derived materials and MOFs composites. In this review, firstly, the classifications and synthesis methods of MOFs materials are presented. Subsequently, the relationship between structure and performance, as well as different strategies for the rational design and controlled synthesis of multifunctional MOFs materials according to the specific requirements of EC sensors are discussed in detail. Finally, it presents conclusive perspectives on the current challenges in using MOFs materials for EC sensors. This paper will offer important guidance in designing and applying MOFs materials in EC sensors.
众所周知,材料的多孔结构为创造一系列具有精确功能的新材料提供了机会。金属有机骨架是由金属节点与有机配体自组装而成的有序多孔材料。研究发现mof是理想的传感材料。近年来,基于mofs的电化学(EC)传感器因其可调节孔径、大表面积和优异的物理/化学稳定性而受到越来越多的关注。通过选择不同的金属中心和有机配体,可以合成各种具有不同结构和功能的纯MOFs,通过对MOFs衍生材料和MOFs复合材料的探索,MOFs家族得到了进一步的扩展。本文首先介绍了mof材料的分类和合成方法。随后,详细讨论了结构与性能之间的关系,以及根据EC传感器的具体要求合理设计和控制合成多功能MOFs材料的不同策略。最后,它提出了结论性的观点,目前在使用mof材料的EC传感器的挑战。本文将对mof材料在电磁传感器中的设计和应用具有重要的指导意义。
Electrical properties of MAH-g-PP modified PP/SEBS matrix semi-conductive composite materials
Xuejing Li, Tianzhen Liu, Xiaolong Chen, Yanhui Wei, Jinliang He, Guochang Li
doi:10.1016/j.compscitech.2024.110657
MAH-g-PP改性PP/SEBS基半导电复合材料的电学性能
Polypropylene (PP) becomes a superior candidate material for new environmental-friendly cable insulation layer with its excellent heat resistance, electrical properties and degradability. At present, most of studies focus on the insulation layer of PP cable. However, there are few studies on semi-conductive shielding layer of PP cable which match its insulation layer. In this paper, polypropylene (PP)/ styrene ethylene butylene styrene (SEBS) is adopted as matrix of PP cable semi-conductive layer to matching its insulation layer. Meanwhile, Maleic anhydride grafted polypropylene (MAH-g-PP) is used to cooperatively improve the compatibility between PP and SEBS. The physicochemical properties, space charge injection properties and compatibility of semi-conductive composites with different CB and MAH-g-PP contents is studied by combining experiment and simulation methods. The experimental results show that the surface roughness of the semi-conductive layer and the space charge inside the insulation layer decrease first and then increase with the increase of CB addition. Among them, the two parameters of 25phr CB semi-conductive layer is the lowest, respectively 13.98 nm and 2.25×10-8C. These two parameters are significantly reduced after the addition of compatibilizer MAH-g-PP, which decreased by 29.47% and 62.22%, respectively. The simulation results show that the Flory-Huggins interaction parameters (χ) of MAH-g-PP with PP and SEBS are -73.3 and -45.2, respectively, which are 236.24% and 107.34% lower than those of PP/SEBS. The χ value of MAH-g-PP/CB is 8.20, which is 33.27% and 9.59% lower than CB/PP and CB/SEBS, respectively. It shows that MAH-g-PP can effectively improve the compatibility of matrix and filler. This work has important guiding significance for the research of semi-conductive layer formulation of PP cable.
聚丙烯(PP)以其优异的耐热性、电性能和可降解性成为新型环保电缆绝缘层的首选材料。目前对PP电缆绝缘层的研究大多集中在PP电缆绝缘层的研究上。然而,对于与PP电缆绝缘层相匹配的半导电屏蔽层的研究却很少。本文采用聚丙烯(PP)/苯乙烯乙烯丁烯苯乙烯(SEBS)作为PP电缆半导电层的基体,与其绝缘层相匹配。同时,用马来酸酐接枝聚丙烯(MAH-g-PP)协同改善PP与SEBS的相容性。采用实验与模拟相结合的方法,研究了不同CB含量和MAH-g-PP含量的半导电复合材料的理化性能、空间电荷注入性能和相容性。实验结果表明,随着炭黑添加量的增加,半导电层表面粗糙度和绝缘层内部空间电荷先减小后增大。其中,25phr CB半导电层的两个参数最低,分别为13.98 nm和2.25×10-8C。添加相容剂MAH-g-PP后,这两个参数分别降低了29.47%和62.22%。仿真结果表明,MAH-g-PP与PP和SEBS的Flory-Huggins相互作用参数(χ)分别为-73.3和-45.2,分别比PP/SEBS低236.24%和107.34%。MAH-g-PP/CB的χ值为8.20,分别比CB/PP和CB/SEBS低33.27%和9.59%。结果表明,MAH-g-PP能有效改善基体与填料的相容性。本工作对PP电缆半导电层配方的研究具有重要的指导意义。