今日更新:Composite Structures 1 篇,Composites Part B: Engineering 2 篇
Composite Structures
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.
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.
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.