今日更新:Composite Structures 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Active vibration control effect of 3D printed cruciform honeycomb laminates based on fiber-reinforced shape memory polymer
Peilei Xu, Xin Lan, Chengjun Zeng, Jinsong Leng, Yanju Liu
doi:10.1016/j.compstruct.2024.118415
基于纤维增强形状记忆聚合物的3D打印十字形蜂窝层压板的主动振动控制效果
Honeycomb structures offer the benefits of being lightweight and having high out-of-face compressive stiffness, making them a popular choice for aerostructures. The present study delineates the design and active vibration control effect for fiber-reinforced cruciform honeycomb laminates (CHLs) characterized by variable parameters. Employing a continuous fiber 3D printer, carbon fiber filament and shape memory polymers (SMPs) were utilized in the fabrication of the specimens. Differential equations of motion for CHLs were deduced from Kirchhoff plate theory. To ascertain their frequency response, these laminates were subjected to a sinusoidal swept frequency excitation. Subsequently, the classical proportional integral derivative (PID) program was employed to scrutinize the efficacy of closed-loop active vibration control on CHLs. The investigation extended to analyzing the impact of active vibration control across laminates with disparate parameters, including an examination of the convergence speed during vibration control procedures. A comparative analysis of simulated versus experimental data revealed a substantial consonance between the two, thereby corroborating the accuracy of the experimental findings. This study offers crucial insights and reference value for the utilization of CHLs in the aerospace industry.
蜂窝结构具有重量轻,抗压刚度高的优点,使其成为航空结构的热门选择。本文研究了变参数纤维增强十字形蜂窝层合板的设计及其振动主动控制效果。采用连续纤维3D打印机,碳纤维长丝和形状记忆聚合物(SMPs)用于样品的制造。利用基尔霍夫板理论推导了chl的运动微分方程。为了确定其频率响应,对这些层合板进行了正弦扫频激励。随后,采用经典的比例积分导数(PID)程序考察了闭环振动主动控制对CHLs的效果。研究扩展到分析具有不同参数的层压板的主动振动控制的影响,包括检查振动控制过程中的收敛速度。模拟数据与实验数据的对比分析揭示了两者之间的一致性,从而证实了实验结果的准确性。本研究为CHLs在航空航天工业中的应用提供了重要的见解和参考价值。
Mechanical characteristics of Si/SiC graded ceramic lattice structures with a triply periodic minimal surface fabricated by laser powder bed fusion
Siqi Wu, Guanglin Sha, Lei Yang, Changshun Wang, Qing Duan, Chunze Yan, Yusheng Shi
doi:10.1016/j.compstruct.2024.118417
激光粉末床熔合制备具有三周期最小表面的Si/SiC梯度陶瓷晶格结构的力学特性
SiC graded ceramic lattice structures (GCLSs) have attracted rising attention owing to outperformed merits including ultra-lightweight and excellent specific strength compared with uniform ceramic lattice structures (UCLSs). In this study, Si/SiC Gyroid GCLSs with variable relative densities (35 % and 45 %) and different gradient directions were designed and fabricated via laser powder bed fusion combined with liquid silicon infiltration techniques. 35 % and 45 % UCLSs were also prepared as a reference. The manufacturing precision and mechanical responses of these CLSs were systematically investigated through compressive tests and micro-computed tomography analysis. The mechanical performances of 35 % GCLSs are lower than that of 35 % UCLSs. The weaker load-bearing capacity in the upper portion and the stress concentration in the inclined load-bearing surface lead to the knockdown of mechanical properties for 35 % GCLSs. The nonlinear superposition of mechanical properties in 45 % GCLSs is the main reason for the superior mechanical performance of 45 % GCLSs compared to 45 % UCLSs. Besides, various theoretical models and finite element simulations were implemented to evaluate the mechanical properties of SiC CLSs. The comparison of compressive strength with other ceramic porous structures emphasized the exceptional mechanical properties (16.07 MPa for 35 % UCLSs and 22.91 MPa for 45 % GCLSs) of Si/SiC CLSs.
SiC梯度陶瓷晶格结构(GCLSs)由于其超轻、比强度优异等优点而受到越来越多的关注。本研究采用激光粉末床熔融结合液态硅渗透技术,设计并制备了相对密度(35 %和45 %)不同梯度方向的Si/SiC Gyroid gcls。制备了35 %和45 %的UCLSs作为参考。通过压缩试验和微计算机断层扫描分析,系统地研究了这些cls的制造精度和力学响应。35% % gcls的力学性能低于35% % UCLSs。35% % gcls的上部承载能力较弱和倾斜承载面应力集中导致其力学性能下降。45 % gcls力学性能的非线性叠加是45 % gcls力学性能优于45 % ucls的主要原因。此外,采用各种理论模型和有限元模拟方法对SiC类材料的力学性能进行了评价。与其他陶瓷多孔结构的抗压强度比较,突出了Si/SiC多孔结构优异的力学性能(35 % ucls为16.07 MPa, 45 % gcls为22.91 MPa)。
Exploring thermal and in-situ mechanical properties of flexible 2D tungsten disulfide foam-polymer composite for thermal management
Kazue Orikasa, Ambreen Nisar, Preyojon Dey, Luiza Benedetti, Tyler Dolmetsch, Tony Thomas, Arvind Agarwal
doi:10.1016/j.compositesb.2024.111743
用于热管理的柔性二维二硫化钨泡沫-聚合物复合材料的热性能和原位力学性能研究
In the realm of thermal management applications, there is a growing need for flexible materials that can efficiently dissipate heat. Polymer composites incorporating two-dimensional (2D) materials offer promising solutions due to their superior thermal and mechanical properties. Tungsten disulfide (WS2) is an excellent filler candidate for polymer composites due to its superior thermal conductivity, mechanical strength, and electrical properties. Unlike graphene, WS2 has a tunable bandgap, exhibits higher thermal resistance in inert atmospheres, is an effective lubricant over a wide temperature range of −190°C to over 800°C, and offers superior gamma radiation shielding. However, high-density 2D material polymer composite fabrication faces challenges due to the agglomeration tendency and sedimentation of heavy nanomaterials within the polymer matrix. This poor dispersion stability negatively impacts the performance and reliability of the composite. We developed a flexible WS2 foam-polydimethylsiloxane (PDMS) composite via freeze drying and vacuum-assisted infiltration, which not only overcomes fabrication challenges but also enables unique filler reinforcement foam designs. The thermal conductivity of WS2-PDMS foam was 1.57 times higher than that of neat PDMS. These thermal properties were modeled using the Lewis-Nielsen model. In-situ tensile tests were conducted to understand the mechanical reinforcing behavior and failure mechanisms of WS2 foam, which were further studied using the Gibson and Ashby model. The addition of WS2 into PDMS resulted in an elastic modulus 1.56 times higher than that of neat PDMS. The composite's mechanical properties were analyzed using the Halpin-Tsai model. These findings highlight the potential of WS2-PDMS composites for flexible thermal management applications.
在热管理应用领域,人们越来越需要能够有效散热的柔性材料。含有二维(2D)材料的聚合物复合材料因其卓越的热性能和机械性能,为我们提供了前景广阔的解决方案。二硫化钨(WS2)具有优异的导热性、机械强度和电气性能,是聚合物复合材料的理想填充物。与石墨烯不同,WS2 具有可调带隙,在惰性气氛中表现出更高的耐热性,在 -190°C 至 800°C 的宽温度范围内是一种有效的润滑剂,并具有优异的伽马辐射屏蔽性能。然而,高密度二维材料聚合物复合材料的制造面临着挑战,原因是重纳米材料在聚合物基质中容易团聚和沉淀。分散稳定性差会对复合材料的性能和可靠性产生负面影响。我们通过冷冻干燥和真空辅助浸润技术开发了一种柔性 WS2 泡沫-聚二甲基硅氧烷(PDMS)复合材料,不仅克服了制造难题,还实现了独特的填充增强泡沫设计。WS2-PDMS 泡沫的热导率是纯 PDMS 的 1.57 倍。这些热性能是通过 Lewis-Nielsen 模型模拟出来的。为了了解 WS2 泡沫的机械增强行为和破坏机制,我们进行了原位拉伸试验,并使用 Gibson 和 Ashby 模型对其进行了进一步研究。在 PDMS 中添加 WS2 后,其弹性模量是纯 PDMS 的 1.56 倍。使用 Halpin-Tsai 模型分析了复合材料的机械性能。这些发现凸显了 WS2-PDMS 复合材料在柔性热管理应用方面的潜力。
Environmental-friendly and fast production of ultra-strong phenolic aerogel composite with superior thermal insulation and ablative-resistance
Can Wu, Lumeng Wang, Xiaojie Yan, He Huang, Yiwu Pan, Hebing Wang, Wei Wang, Shuai Yuan, Jiahui Fan, Xiangyu Jin, Changqing Hong, Xinghong Zhang
doi:10.1016/j.compscitech.2024.110776
环保、快速生产具有优异保温、耐烧蚀性能的超强酚醛气凝胶复合材料
There is an urgent need for developing “low-carbon” synthesis technology to prepare aerogel composites with both high mechanical strength and efficient thermal insulation for applications of modern aerospace and energy saving. Herein, we propose a strategy for fabricating lightweight phenolic aerogel composites with thick-united connected nano-structure and good aerogel-fiber interfacial compatibility. The specific micro-nano structure and optimized material synergism endow the aerogel composites with an ultrahigh tensile strength (12.84±0.64 MPa), bending strength (24.69±1.96 MPa) and compressive strength (1.7±0.053 MPa under 5% strain), as well as low thermal conductivity (0.0541±0.0003 W/(m·K)). The aerogel composites behave excellent ablation-resistance under the flame of 1200 °C within 30 min and maintain a cold-side temperature of 56.07 °C without any shape change. The rigid-flexible comminated aerogel composites open up a new technical track for developing lightweight thermal protective composites with high strength, toughness, and efficient thermal insulation demanded in extreme environments.
迫切需要发展“低碳”合成技术,制备既具有高机械强度又具有高效保温性能的气凝胶复合材料,以满足现代航空航天和节能应用的需要。在此,我们提出了一种具有厚连接纳米结构和良好的气凝胶-纤维界面相容性的轻质酚醛气凝胶复合材料的制备策略。特殊的微纳结构和优化的材料协同作用使气凝胶复合材料具有超高的抗拉强度(12.84±0.64 MPa)、抗弯强度(24.69±1.96 MPa)和抗压强度(5%应变下1.7±0.053 MPa)和低导热系数(0.0541±0.0003 W/(m·K))。该气凝胶复合材料在1200℃火焰下30 min内具有优异的耐烧蚀性能,冷侧温度为56.07℃时无任何形状变化。刚柔混合气凝胶复合材料为开发具有高强度、高韧性和高效绝热的轻质热防护复合材料开辟了一条新的技术道路。