今日更新:Composite Structures 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Design and performance simulation of hybrid hemp/glass fiber composites for automotive front bumper beams
Napat Nawawithan, Peerapat Kittisakpairach, Supakit Nithiboonyapun, Kitchanon Ruangjirakit, Pattaramon Jongpradist
doi:10.1016/j.compstruct.2024.118003
用于汽车前保险杠横梁的混合麻/玻璃纤维复合材料的设计与性能模拟
This study investigates the use of hemp/glass fiber reinforced epoxy composites for designing automotive front bumper beams, focusing on crashworthiness and pedestrian safety. The composite bumper beam model is evaluated through low- and high-velocity crash simulations and pedestrian leg form impact tests using LS-DYNA software. Optimal stacking sequences are analyzed, with high-strength glass fibers positioned on the outer layers to bear impact loads and low-density hemp fibers in the middle. The hybrid hemp (H)/glass (G) fiber composite laminate can absorb up to 90 % of the impact energy absorbed by a glass fiber composite, with a ± 45° fiber orientation, showing exceptional energy absorption capabilities. The [G(±45°)4, H(±45°)4]S composite bumper beam offers superior impact performance, safety, and a weight reduction of 49.2 % compared to a commercial steel bumper beam. This study highlights the potential of natural fiber composites as sustainable alternatives in automotive design.
本研究调查了麻/玻璃纤维增强环氧树脂复合材料在汽车前保险杠横梁设计中的应用,重点关注耐撞性和行人安全。通过低速和高速碰撞模拟以及使用 LS-DYNA 软件进行的行人腿部冲击测试,对复合材料保险杠横梁模型进行了评估。对最佳堆叠顺序进行了分析,高强度玻璃纤维位于外层以承受冲击载荷,低密度麻纤维位于中间。混合麻(H)/玻璃(G)纤维复合层压板吸收的冲击能量可达玻璃纤维复合材料的 90%,纤维取向为 ±45°,显示出卓越的能量吸收能力。G(±45°)4,H(±45°)4]S 复合材料保险杠横梁具有卓越的冲击性能和安全性,与商用钢保险杠横梁相比,重量减轻了 49.2%。这项研究凸显了天然纤维复合材料作为汽车设计中可持续替代品的潜力。
Thermomechanical characterisation of reprocessable, siloxane-based, glass-fibre-reinforced vitrimers
Virginia Amfilochiou, Tapas Debsharma, Ives De Baere, Lode Daelemans, Filip Du Prez, Wim Van Paepegem
doi:10.1016/j.compositesb.2024.111354
硅氧烷基玻璃纤维增强型可再加工玻璃纤维的热力学特性分析
Polymer composites have been extensively used for the last 30 years in the automotive, green-energy, maritime and aerospace industries. While the demands of composites' applications are increasing, complications are arising regarding their sustainability. In this work, a siloxane-based vitrimer with fast stress-relaxation, and its Glass-Fibre-Reinforced Vitrimer (GFRV) were manufactured and mechanically characterised as a sustainable alternative to thermoset composites produced by infusion. Dynamic mechanical analysis and differential scanning calorimetry were performed to identify the ageing effect on the glass-transition temperature of the materials. Tensile and in-plane shear tests were executed to investigate the materials’ performance at elevated temperature. The results were compared to the ones of a thermoset benchmark and showed that after ageing and up to 50 °C, both the neat vitrimer and its corresponding composite exhibited a thermomechanical performance comparable to their thermoset counterparts. GFRV specimens were then successfully reprocessed by hot-pressing up to two consecutive cycles. The GFRV specimen was thermoformed into an omega-stiffener profile by the first hot-pressing cycle, while its flat profile was restored during the second cycle. Finally, the reprocessing results were evaluated by optical microscopy, demonstrating that the newly developed advanced GFRV is indeed a viable, sustainable alternative.
过去 30 年来,聚合物复合材料已广泛应用于汽车、绿色能源、航海和航空航天等行业。在复合材料应用需求不断增长的同时,复合材料的可持续发展问题也日益复杂。在这项研究中,我们制造了一种具有快速应力松弛功能的硅氧烷基玻璃聚合物及其玻璃纤维增强玻璃聚合物(GFRV),并对其进行了机械性能表征,以作为通过导流生产的热固性复合材料的可持续替代品。通过动态机械分析和差示扫描量热法确定了老化对材料玻璃化转变温度的影响。为了研究材料在高温下的性能,还进行了拉伸和平面剪切试验。测试结果与热固性材料的测试结果进行了比较,结果表明,经过高达 50 ° C 的老化后,纯玻璃聚合物及其相应复合材料的热机械性能与热固性材料相当。随后,GFRV 试样通过连续两个循环的热压成功地进行了再加工。在第一个热压循环中,GFRV 试样被热成型为欧米茄加固轮廓,而在第二个循环中,其扁平轮廓得以恢复。最后,通过光学显微镜对再加工结果进行了评估,证明新开发的先进 GFRV 确实是一种可行的、可持续的替代品。
High-efficiency electromagnetic wave absorption of lightweight Nb2O5/CNTs/polyimide with excellent thermal insulation and compression resistance integration
Yuanyuan Zeng, Lan Long, Jiaqi Yu, Yuqi Li, Yang Li, Wei Zhou
doi:10.1016/j.compscitech.2024.110531
轻质 Nb2O5/CNTs/ 聚酰亚胺的高效电磁波吸收技术,具有优异的隔热性和抗压性一体化性能
With the widespread application of electronic devices, multifunctional electromagnetic wave (EMW) absorbing materials suitable for complex high-temperature and high-pressure environments, have attracted tremendous research attention. Herein, multifunctional polyimide (PI) composites doped with fluffy Nb2O5/CNTs microspheres (NBCP) were prepared by combining the ultrasonic spraying process and freeze-drying technique. Introduction of fillers results in the formation of diverse conduction paths and heterogeneous interfaces, which enhance the dielectric loss. Furthermore, the multi-porous structure of the PI matrix induces multiple reflection scattering events and improves the impedance matching. Such a multi-loss mechanism endows NBCP with an excellent EMW absorption performance. At 15 vol% filling, the minimum reflection loss is −41.66 dB, the effective absorption bandwidth is 2.63 GHz, and the radar cross-section is reduced by 85%. Furthermore, NBCP exhibits outstanding mechanical properties and a thermal insulation of over 100 °C in thermal environment at 150 °C. The proposed multifunctional NBCP is thus an efficient EMW absorber that offers significant potential for applications in harsh environments.
随着电子设备的广泛应用,适用于复杂高温高压环境的多功能电磁波(EMW)吸收材料引起了人们的极大关注。本文结合超声喷涂工艺和冷冻干燥技术,制备了掺杂绒毛状 Nb2O5/CNTs 微球(NBCP)的多功能聚酰亚胺(PI)复合材料。填料的引入导致形成了不同的传导路径和异质界面,从而提高了介电损耗。此外,PI 基体的多孔结构还诱导了多重反射散射事件,改善了阻抗匹配。这种多重损耗机制赋予了 NBCP 极佳的电磁波吸收性能。当填充量为 15 vol% 时,最小反射损耗为 -41.66 dB,有效吸收带宽为 2.63 GHz,雷达截面减少了 85%。此外,NBCP 还具有出色的机械性能,在 150 °C 的热环境中隔热性能超过 100 °C。因此,所提出的多功能 NBCP 是一种高效的电磁波吸收器,在恶劣环境中的应用潜力巨大。