今日更新:Composite Structures 1 篇,Composites Part B: Engineering 2 篇
Fatigue behaviour of glass-fibre-reinforced polymers: Numerical and experimental characterisation
B. Alcayde, M. Merzkirch, A. Cornejo, S. Jiménez, E. Marklund, L.G. Barbu
doi:10.1016/j.compstruct.2024.118057
玻璃纤维增强聚合物的疲劳行为:数值和实验表征
This work presents a novel numerical methodology to model the degradation and failure of composite materials like GFRP submitted to monotonic and high cycle fatigue loads. This is done by using the Serial-Parallel Rule of Mixtures homogenisation technique together with a proper mechanical characterisation of the constituent materials of the composite. This paper also proposes an efficient way of estimating the fatigue properties of each of the material constituents (fibre or matrix) to comply with the experimental results obtained at composite level; this enables to estimate the fatigue strength of any stacking/orientation of fibres with only one mechanical characterisation of the material properties. A comparison of the results obtained analytically and experimentally for GFRP is presented. The results show the applicability and accuracy of the proposed methodology in this field.
本研究提出了一种新颖的数值方法,用于模拟 GFRP 等复合材料在单调和高循环疲劳载荷作用下的降解和失效。该方法采用了串并联混合物均质化技术,并对复合材料的组成材料进行了适当的机械特性分析。本文还提出了一种估算每种材料成分(纤维或基体)疲劳特性的有效方法,以符合在复合材料层面获得的实验结果;这使得只需对材料特性进行一次机械表征,就能估算出任何纤维堆叠/取向的疲劳强度。本文对 GFRP 的分析和实验结果进行了比较。结果表明了所建议的方法在该领域的适用性和准确性。
Microstructure and fracture toughness of a Nb–Ti–Si-based in-situ composite fabricated by laser-based directed energy deposition
Yunlong Li, Xin Lin, Yunlong Hu, Wei Fan, Xuehao Gao, Jun Yu, Hongbiao Dong, Weidong Huang
doi:10.1016/j.compositesb.2024.111427
利用激光定向能沉积技术制造的铌钛硅基原位复合材料的微观结构和断裂韧性
Laser-based directed energy deposition (LDED), a significant integrated preparation technique combining material design and production, has been progressively used to manufacture Nb–Ti–Si-based in-situ composites. However, it is commonly known that Nb–Si-based in-situ composites have low room-temperature fracture toughness. Herein, we have designed a novel Nb–40Ti–10Si–5Al–2V (at.%) composite, the microstructure of LDED-built composite is made up of Nbss and γ-Nb5Si3, the formation of γ-Nb5Si3 precipitate in the Nbss phase with an orientation relationships (ORs) of [1110]γ//[011]Nbss, (101¯0)γ//(011)Nbss and (12¯11)γ//(200)Nbss. The composite has Nbss, Nb3Si and γ-Nb5Si3 phases after heat treatment at 1400 °C for 30h, and δ-Nb11Si4 precipitate has formed in the Nbss phase with an ORs of [100]Nbss//[010]δ, (010)Nbss//(010)δ. The composite processing Nb–40Ti–10Si–5Al–2V (at.%) has outstanding toughness (21.62MPa·m1/2). It has ascertained that the room-temperature fracture toughness of Nb–Si-based in-situ composite is positively impacted by the high concentration of Ti.
激光定向能沉积(LDED)是一种集材料设计和生产于一体的重要集成制备技术,已被逐步用于制造铌钛硅基原位复合材料。然而,众所周知,铌硅基原位复合材料的室温断裂韧性较低。在此,我们设计了一种新型 Nb-40Ti-10Si-5Al-2V (at. LDED-built复合材料的微观结构由Nbss和γ-Nb5Si3组成,在Nbss相中形成γ-Nb5Si3沉淀,其取向关系(ORs)为[1110]γ//[011]Nbss、(101¯0)γ//(011)Nbss和(12¯11)γ//(200)Nbss。在 1400 °C 下热处理 30 小时后,复合材料具有 Nbss、Nb3Si 和 γ-Nb5Si3 三相,并且在 Nbss 相中形成了 δ-Nb11Si4 沉淀,其 ORs 为 [100]Nbss/[010]δ, (010)Nbss//(010)δ. Nb-40Ti-10Si-5Al-2V(at.%)复合材料具有出色的韧性(21.62MPa-m1/2)。研究证实,高浓度 Ti 对 Nb-Si 基原位复合材料的室温断裂韧性有积极影响。
Tailoring the electron free path in an ultra-lightweight gas-solid composite insulation system for high dielectric strength
Bo Song, Ming Ren, Yujie Liu, Qian Wu, Zhang Yang, Chongxing Zhang, Ming Dong, Yifei Wang
doi:10.1016/j.compositesb.2024.111429
调整超轻型气固复合绝缘系统中的电子自由路径,实现高介电强度
Reliable electric insulation is the premise for the application of high-voltage technologies, such as power transmission, emergent electrified transportations, and advanced propulsion systems. With the current insulation strategy, the credibility of insulation system depends on the sufficient insulation materials usage, suffering from bulky structure, expensive production costs and environmental pollution. Here, we propose a strategy that applies a lightweight multiple-barrier skeleton in gas insulation to tailor electron free path and restrain electron avalanche, thus realizing a high insulation strength with less material usage. This strategy is verified by the composite insulation of porous polyimide aerogel and various types of insulating gases. It achieves a comparable insulation strength to conventional polymers by less than 10% materials usage. With above insulation strategy, a 152.5% improvement in power density and a 54.6% weight reduction are acquired in the cable system for more or all electric aircraft. This strategy inspires the design of efficient insulation solution with both high breakdown strength and lightweight.
可靠的电气绝缘是输电、新兴电气化交通和先进推进系统等高压技术应用的前提。在现有的绝缘策略下,绝缘系统的可靠性取决于绝缘材料的充分使用,存在结构笨重、生产成本高昂和环境污染等问题。在此,我们提出了一种在气体绝缘中应用轻质多屏障骨架的策略,以调整电子自由路径并抑制电子雪崩,从而以较少的材料用量实现较高的绝缘强度。多孔聚酰亚胺气凝胶和各种绝缘气体的复合绝缘验证了这一策略。它以不到 10% 的材料用量实现了与传统聚合物相当的绝缘强度。采用上述绝缘策略后,更多或全电动飞机的电缆系统的功率密度提高了 152.5%,重量减轻了 54.6%。这一策略启发我们设计出既具有高击穿强度又重量轻的高效绝缘解决方案。