今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Anti-bird-strike behavior of M40J carbon fiber reinforced plastic laminates
Liangbin Chen, Xueyu Lin, Risheng Bai, Zhenqiang Zhao, Zaoyang Guo
doi:10.1016/j.compstruct.2024.118094
M40J 碳纤维增强塑料层压板的防鸟击性能
In this paper the anti-bird-strike behavior of M40J 12 K/7901 carbon fiber reinforced plastic (CFRP) laminates is investigated numerically and experimentally. Gelatin artificial birds were used to perform the bird-strike tests on various M40J CFRP laminated square plates with a wide range of impact velocities. Ultrasonic C-scan was utilized to measure the damage of the tested plates. Finite Element (FE) Models were created to simulate the bird-strike tests and the numerical predictions agreed well with the experimental results. The threshold values of bird’s impact velocity V0 when fibers begin to break were studied for 4 types of plates under normal and oblique bird-strikes to evaluate the anti-bird-strike capability of the laminates. The fiber damage after a flock-strike of two small birds was then investigated and the results suggest that the investigation of one large bird strike is more convincing in qualifying the anti-bird-strike resistance than that of a flock-strike of two small birds. Finally, a ply stacking sequence optimization in anti-bird-strike stiffness was obtained by the global optimization method.
本文对 M40J 12 K/7901 碳纤维增强塑料(CFRP)层压板的抗鸟击行为进行了数值和实验研究。使用明胶人造鸟对各种 M40J CFRP 层压方板进行鸟击试验,冲击速度范围很宽。利用超声波 C 扫描测量受测板材的损坏情况。建立了有限元(FE)模型来模拟鸟击试验,数值预测结果与实验结果吻合良好。研究了 4 种板材在正向和斜向鸟击下纤维开始断裂时的鸟击速度阈值 V0,以评估层压板的抗鸟击能力。然后研究了两只小鸟成群撞击后的纤维损伤情况,结果表明,对一只大鸟撞击的研究比两只小鸟成群撞击的研究在鉴定抗鸟击能力方面更有说服力。最后,通过全局优化法得出了抗鸟击刚度的层叠顺序优化方案。
Thermal runaway criterion for thick polymer composites
Rikard Gebart
doi:10.1016/j.compositesa.2024.108187
厚聚合物复合材料的热失控标准
An analytical solution has been developed for the curing of thick polymer composite laminates that shows how the temperature profile responds to arbitrary changes to the material properties and process parameters and that curing with slow reactions and a low exotherm temperature is impossible if the Damköhler number is above a well-defined limit. The thermal runaway criterion can be recast as a criterion for the maximum allowable thickness of the laminate. The thermal runaway criterion was found to agree well with some results for thick laminates from the literature, but the peak temperature in the laminate was underpredicted for stable conditions. The model has a constant that can be adjusted to improve the peak temperature prediction, but more validation data is needed before the model can be optimized to simultaneously predict the peak temperature and thermal runaway with high accuracy.
针对厚聚合物复合材料层压板的固化问题开发了一种分析解决方案,该方案显示了温度曲线如何对材料特性和工艺参数的任意变化做出反应,并显示了如果达姆克勒数高于一个明确定义的极限,则不可能出现反应缓慢和放热温度低的固化现象。热失控标准可重新作为层压板最大允许厚度的标准。研究发现,热失控准则与文献中一些厚层压板的结果十分吻合,但对稳定条件下层压板的峰值温度预测不足。该模型有一个常数,可以通过调整来改善峰值温度预测,但还需要更多的验证数据,才能对模型进行优化,以同时高精度地预测峰值温度和热失控。
Superior photoluminescence of quantum dot displays via organic-inorganic composite scatterers
MinSu Kim, DaYeon Lee, HaYoung Jung, Seung Hee Lee
doi:10.1016/j.compositesb.2024.111425
通过有机-无机复合散射体实现量子点显示器的卓越光致发光性能
High color purity of quantum dot organic light-emitting diodes (QD-OLEDs) can be achieved by blue OLED light to stimulate pixelized green and red QDs within a color conversion layer, providing high color conversion efficiency in commercialized displays. However, enhancing external quantum efficiency (EQE) and minimizing blue light leakage remain significant challenges. To resolve these issues, we have developed an organic-inorganic composite system comprising quantum dots (QDs), liquid crystal (LC), polymer, and inorganic nanoparticles, like titanium dioxide (TiO2). The best EQE was enhanced by ∼81.9% when TiO2 of 6 wt%. More importantly, the EQE was enhanced by ∼58.6% when TiO2 of 3 wt% while TiO2 nanoparticles were well-dispersed and stable without aggregation for more than 3 days, which is crucial for preventing nozzle blockages during inkjet printing in manufacturing processes. We believe our innovative approach is promising for boosting color conversion efficiency by exciting highly concentrated green and red QDs with blue light while also overcoming inherent fabrication hurdles associated with high concentrations of inorganic scatterers.
量子点有机发光二极管(QD-OLED)的高色彩纯度可通过蓝色 OLED 光激发色彩转换层内像素化的绿色和红色量子点来实现,从而在商业化显示器中提供高色彩转换效率。然而,提高外部量子效率(EQE)和最大限度地减少蓝光泄漏仍然是重大挑战。为了解决这些问题,我们开发了一种有机无机复合系统,由量子点(QDs)、液晶(LC)、聚合物和无机纳米粒子(如二氧化钛(TiO2))组成。当二氧化钛含量为 6 wt% 时,最佳 EQE 增强了 ∼81.9%。更重要的是,当 TiO2 含量为 3 wt% 时,EQE 提高了 ∼58.6% ,同时 TiO2 纳米粒子分散良好,且在 3 天以上的时间里都保持稳定,没有聚集现象,这对于在制造过程中防止喷墨打印时喷嘴堵塞至关重要。我们相信,我们的创新方法有望通过蓝光激发高浓度绿光和红光 QDs 来提高色彩转换效率,同时还能克服与高浓度无机散射体相关的固有制造障碍。
Capacitive BaTiO3-PDMS hand-gesture sensor: Insights into sensing mechanisms and signal classification with machine learning
Frances Danielle M. Fernandez, Munseong Kim, Sukeun Yoon, Jihoon Kim
doi:10.1016/j.compscitech.2024.110581
电容式 BaTiO3-PDMS 手势传感器:利用机器学习深入了解传感机制和信号分类
Flexible sensors have gained extensive interest because of their versatile applications in healthcare, robotics, and wearable devices. This study introduces a capacitive sensor utilizing barium titanate oxide (BaTiO3)-polydimethylsiloxane (PDMS) for bending sensing and addresses crucial performance parameters including sensitivity, repeatability, response time, and durability. The sensor exhibited a notable capacitance change of 42.85% in conjunction with fast (1 s) responses and recovery times, and minimal hysteresis (<2%). Its reliable performance across varying bending rates and durability through extensive cyclic tests underscore its applicability in real-world scenarios. Importantly, the sensor's capabilities were enhanced by integrating machine learning (ML), achieving an impressive accuracy of 97.11% in recognizing hand-sign language gestures. Furthermore, finite element analysis was employed to validate the correlation between the increase in compression-induced packing density and capacitance enhancement. This holistic integration of advanced materials, computational simulations, and ML not only extends the boundaries of sensor technology but also holds promise for revolutionizing human–machine interactions, aiding speech-impaired individuals, and enriching virtual reality experiences. This study represents a pivotal advancement in the field of flexible sensors and the unlocking of new dimensions of their applications.
柔性传感器因其在医疗保健、机器人和可穿戴设备中的广泛应用而受到广泛关注。本研究介绍了一种利用钛酸钡氧化物(BaTiO3)-聚二甲基硅氧烷(PDMS)进行弯曲传感的电容式传感器,并探讨了灵敏度、可重复性、响应时间和耐用性等关键性能参数。该传感器的电容变化率高达 42.85%,响应速度快(1 秒),恢复时间短,滞后极小(<2%)。该传感器在不同弯曲率下的可靠性能以及通过大量循环测试的耐用性,都突出表明了它在实际应用中的适用性。重要的是,该传感器通过集成机器学习(ML)功能,在识别手势语言手势方面达到了令人印象深刻的 97.11% 的准确率。此外,还采用了有限元分析来验证压缩引起的堆积密度增加与电容增强之间的相关性。这种先进材料、计算模拟和 ML 的整体集成不仅扩展了传感器技术的边界,而且有望彻底改变人机交互、帮助语言障碍人士和丰富虚拟现实体验。这项研究代表了柔性传感器领域的关键性进步,并开启了其应用的新维度。