今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 1 篇
Prediction and optimization of global temperature field of composite materials under multiple heat sources
Sen Yang, Wen Yao, Lin-Feng Zhu, Richard-Kwok-Kit Yuen, Liao-Liang Ke
doi:10.1016/j.compstruct.2024.117974
多热源下复合材料全局温度场的预测与优化
The property measurement and structure optimization of composite materials are difficult topics due to the diversity of combinations of composite constituents and complexity of their application environments. The distribution of composite constituents and heat sources can cause heat aggregation phenomenon which may lead to failure of materials. In this paper, we first propose a deep learning-based surrogate model (DLBSM) which can quickly and accurately achieve the end-to-end prediction between the layout of composite materials under multiple heat sources and its temperature field. The prediction result depicts that the coefficient of determination for the maximum and average temperature of all cases exceeds 0.996. Then, the layout optimization is transformed into a combinatorial optimization problem, and the DLBSM is combined with optimization algorithm to optimize the maximum temperature, temperature gradient, and uniformity of the temperature field. The optimized maximum temperature and temperature gradient are significantly reduced, while the temperature uniformity is improved. These enhancements effectively reduce the probability of failure in composites. This approach can significantly improve the efficiency of thermal behavior prediction of composite and its layout optimization compared with finite element method (FEM).
由于复合材料成分组合的多样性及其应用环境的复杂性,复合材料的性能测量和结构优化是一个难题。复合材料成分和热源的分布会造成热聚集现象,从而导致材料失效。本文首先提出了一种基于深度学习的代用模型(DLBSM),可以快速准确地实现复合材料在多热源下的布局与温度场之间的端到端预测。预测结果表明,所有情况下最高温度和平均温度的判定系数均超过 0.996。然后,将布局优化转化为组合优化问题,并将 DLBSM 与优化算法相结合,优化温度场的最高温度、温度梯度和均匀性。优化后的最高温度和温度梯度明显降低,温度均匀性得到改善。这些改进有效降低了复合材料的失效概率。与有限元法(FEM)相比,这种方法可以大大提高复合材料热行为预测及其布局优化的效率。
Thermomechanical characterisation of a thermoplastic polymer and its short glass fibre reinforced composite: Influence of fibre, fibre orientation, strain rates and temperatures
Peihao Song, David J. Chapman, Aaron M. Graham, Bratislav Lukić, Alexander Rack, Clive R. Siviour
doi:10.1016/j.compositesa.2024.108099
热塑性聚合物及其短玻璃纤维增强复合材料的热力学特性:纤维、纤维取向、应变率和温度的影响
Polycarbonate composites are widely used in products exposed to high strain rate deformation. This paper investigates the thermomechanical properties of polycarbonate and 20 wt% glass fibre reinforced polycarbonate to provide characterisation data and improved mechanistic understanding of the response to load, supported by Dynamic Mechanical Analysis and time–temperature superposition. Compressive behaviour is characterised from 0.001 to 5000 s−1 at room temperature and from −60 to 120 °C at 0.01 s−1; and a thermal imaging camera used to obtain temperature rise data. Quasi-static tensile experiments were also performed in different orientations relative to the injection flow direction. High-rate compression experiments are performed with X-ray imaging. As well as information about rate dependence of yield stresses and softening in the two materials, these data show how adiabatic shear band formation can cause significant softening in the composite. These data will enhance application of these polymers and facilitate development of advanced thermo-mechanical models.
聚碳酸酯复合材料广泛应用于承受高应变率变形的产品中。本文研究了聚碳酸酯和 20 wt%玻璃纤维增强聚碳酸酯的热机械特性,通过动态机械分析和时间-温度叠加,提供特性数据并提高对负载响应的机械理解。在室温条件下,以 0.001 至 5000 s-1 的速度对压缩行为进行表征;在 -60 至 120 °C 的条件下,以 0.01 s-1 的速度对压缩行为进行表征;并使用热像仪获取温升数据。此外,还在相对于注入流动方向的不同方向上进行了准静态拉伸实验。利用 X 射线成像技术进行了高速压缩实验。除了两种材料屈服应力和软化的速率依赖性信息外,这些数据还显示了绝热剪切带的形成如何导致复合材料的显著软化。这些数据将促进这些聚合物的应用,并有助于开发先进的热机械模型。
Physical and mechanical properties of nano-modified polybenzoxazine nanocomposite laminates: Pre-flight tests before exposure to low Earth orbit
Kyungil Kong, Joseph Gargiuli, Konstantina Kanari, Mayra Yadira Rivera Lopez, James Thomas, George Worden, Lucas Lu, Sean Cooper, Stuart Donovan-Holmes, Alexander Mathers, Nick Hewlings, Agnieszka Suliga, Johanna Wessing, Sebastien Vincent-Bonnieu, Katharine Robson Brown, Ian Hamerton
doi:10.1016/j.compositesb.2024.111311
纳米改性聚苯并恶嗪纳米复合材料层压板的物理和机械性能:暴露于低地球轨道前的飞行前测试
Polybenzoxazine (PBZ) formulations based on commercial components and modified with polyhedral oligomeric silsesquioxanes (POSS, 5 wt.% and 10 wt.%) have been scaled up for industrialisation, and their processing characteristics determined using thermal analysis and rheometry. The ultimate glass transition temperatures for the cured PBZ resins are increased by catalysis and by the incorporation of POSS. Carbon fibre reinforced polymer (CFRP) laminates (500 mm × 500 mm x 3 mm) were manufactured using resin transfer moulding and subjected to a suite of mechanical tests. The addition of 5 wt.% POSS to the PBZ formulation leads to substantial improvements in both strength (tensile, flexural, short beam shear, and compression) and modulus (tensile, flexural, and compression). The CFRP specimens were subjected to a suite of pre-flight qualification tests prior to deployment in low Earth orbit. When the CFRP laminates were exposed to <1 × 10−5 mbar and 125 °C, the total mass loss recorded for each sample was <1 wt.%. The introduction of POSS at both levels of incorporation improves erosion yield following exposure to high atomic oxygen flux and the ratio of solar absorptance (α) to emittance (ε) remained constant following simulated solar exposure. The outcome was that the three PBZ CFRP samples passed their pre-flight tests.
以商用成分为基础并用多面体低聚硅倍半氧烷(POSS,5 wt.% 和 10 wt.%)改性的聚苯并恶嗪(PBZ)配方已按比例进行了工业化生产,并使用热分析和流变仪确定了其加工特性。通过催化和加入 POSS,固化 PBZ 树脂的最终玻璃化转变温度得到了提高。使用树脂传递模塑法制造了碳纤维增强聚合物(CFRP)层压板(500 毫米 × 500 毫米 × 3 毫米),并对其进行了一系列机械测试。在 PBZ 配方中添加 5 wt.% 的 POSS 后,强度(拉伸、弯曲、短梁剪切和压缩)和模量(拉伸、弯曲和压缩)均有大幅提高。在低地球轨道部署之前,CFRP 试样接受了一系列飞行前鉴定测试。当 CFRP 层压板暴露在 <1 × 10-5 mbar 和 125 °C 的环境中时,每个试样记录到的总质量损失均小于 1 wt.%。在两个添加水平上引入 POSS 可提高暴露于高原子氧通量后的侵蚀产量,并且在模拟太阳暴露后,太阳吸收率(α)与发射率(ε)之比保持不变。结果表明,三种 PBZ CFRP 样品均通过了飞行前测试。
Optimisation of ultrasonic welding process of carbon/epoxy composites using Nylon-based or PES thermoplastic interlayers
L. Calabrese, G. Cicala, G. Di Bella, E. Proverbio, C. Tosto, L. Saitta
doi:10.1016/j.compositesb.2024.111318
优化使用尼龙基或聚醚砜热塑性夹层的碳/环氧树脂复合材料的超声波焊接工艺
The aim of this study is to investigate ultrasonic welding in carbon fibre-reinforced thermosetting composites by optimizing process parameters, specifically sonotrode pressure and ultrasound application time. Joining is accomplished by incorporating electrospun veils, consisting of either polyether sulfone or nylon, into the outer layers of the composite laminates. Single lap shear tests were conducted to evaluate the mechanical strength of the joints and identify failure mechanisms. The results highlight a significant influence of the thermoplastic interlayer. Polyether Sulfone ensures consistently lower mechanical properties, while Nylon contributes to higher strength. In both scenarios, these joints show promising applications, particularly in sports automotive contexts where rapid and reliable part welding is crucial.
本研究旨在通过优化工艺参数,特别是超声电极压力和超声应用时间,研究碳纤维增强热固性复合材料的超声波焊接。通过在复合材料层压板的外层加入由聚醚砜或尼龙组成的电纺纱来实现接合。为评估接合处的机械强度并确定失效机制,进行了单搭接剪切试验。测试结果表明,热塑性夹层具有重大影响。聚醚砜确保了持续较低的机械性能,而尼龙则有助于提高强度。在这两种情况下,这些接头都显示出良好的应用前景,尤其是在运动型汽车领域,快速可靠的零件焊接至关重要。
The impacts of CaCO3 deposition in natural wood on its viscoelastic properties
Hyunjun Choi, Laura E. Dalton, Ilona Peszlen, Moe Pourghaz
doi:10.1016/j.compositesb.2024.111324
天然木材中 CaCO3 沉积对其粘弹性能的影响
In this study, we discuss the methods used for depositing calcium carbonate (CaCO3) and the resulting 2D and 3D particle distributions of CaCO3 in two types of wood, which were quantified using scanning electron microscopy (SEM) and X-ray computed tomography (CT). We also present the results of dynamic mechanical analysis (DMA), which was used to measure the impact of CaCO3 deposition on the viscoelastic properties of the wood. X-ray CT scanning showed that CaCO3 deposits inside the wood scaffold with increased amounts as the deposition cycles were iterated. However, DMA results did not indicate significant improvement in storage moduli (E′) of CaCO3 deposited wood. SEM images revealed that the particles did not fill all the voids to provide stress transfer between the wood scaffold and the particles, indicating a lack of composite action between the wood and CaCO3 components. To address this issue, we hypothesized that heat-pressing would lead to a mechanical bond between the particles and the matrix. After heat-pressing, DMA results showed a dramatic increase in E′ not only in CaCO3 deposited wood samples but also in control wood samples. In other words, the densification of the structure led to significant increases in E′, primarily due to densification, while the impact of the presence of CaCO3 particles was minimal. This is mainly because the volume fraction of the deposited CaCO3 particles is small as compared to the total volume of the composite.
在本研究中,我们讨论了沉积碳酸钙 (CaCO3) 的方法以及两种木材中 CaCO3 的二维和三维颗粒分布,并使用扫描电子显微镜 (SEM) 和 X 射线计算机断层扫描 (CT) 对其进行了量化。我们还介绍了动态机械分析 (DMA) 的结果,该分析用于测量 CaCO3 沉积对木材粘弹性能的影响。X 射线 CT 扫描显示,随着沉积周期的反复进行,CaCO3 在木材支架内的沉积量不断增加。然而,DMA 结果表明,沉积 CaCO3 的木材的存储模量(E′)并没有明显改善。SEM 图像显示,颗粒没有填满所有空隙,无法在木材支架和颗粒之间提供应力传递,这表明木材和 CaCO3 成分之间缺乏复合作用。为了解决这个问题,我们假设热压将导致颗粒和基质之间的机械结合。热压后,DMA 结果表明,不仅 CaCO3 沉积木材样品的 E′显著增加,而且对照木材样品的 E′也显著增加。换句话说,结构致密化导致 E′显著增加,主要原因是致密化,而 CaCO3 颗粒的存在影响很小。这主要是因为沉积 CaCO3 颗粒的体积分数与复合材料的总体积相比很小。
The investigation and fabrication of novel ballistic composites with checkerboard-shaped lay-up design to improve ballistic performances
Feilong Han, Chenghao Wang, Ya Zhang, Ziyu Wang, Hangyu Yue, Lishuai Zong, Jinyan Wang, Xigao Jian
doi:10.1016/j.compscitech.2024.110511
研究和制造采用棋盘格形铺层设计的新型弹道复合材料,以提高弹道性能
High-performance and lightweight ballistic composites prepared through layer-by-layer lay-up of matrix and fabric have attracted significant interest. However, the traditional full-coverage lay-up design constrains the energy absorption of the composites during ballistic impact. Therefore, novel ballistic composites configured with checkerboard-shaped lay-up design were studied, using checkerboard-shaped polycarbonate (PC) films and aramid plain-woven fabrics. The effect of the size and cross-layered distribution of the checkerboard-shaped PC films was investigated. Compared with the full-coverage lay-up design, the checkerboard-shaped lay-up design can effectively improve the ballistic performance. For checkerboard-shaped lay-up design ballistic composites, the ballistic performances exhibited minor variation when impacting PC regions but gradually increased with the size of the fabric regions when impacting aramid fabric regions. The ballistic performance of interval cross-layered checkerboard-shaped PC films also increased with the number of interval layers. When impacting PC regions, the primary ballistic mechanisms were compression/shear and shear/tensile failures; however, when delamination and stress waves propagated into the regions without PC films, the checkerboard lay-up design allowing for effective energy absorption through tensile failure by fabrics. When impacting aramid fabric regions, the primary ballistic mechanisms were shear/tensile failure and tensile failure. However, when the size of aramid fabric region was insufficient, the near PC region can restrict transverse deformation of the fabrics, which did not benefit the ballistic performance.
通过逐层铺设基体和织物制备的高性能轻质弹道复合材料引起了人们的极大兴趣。然而,传统的全覆盖铺层设计限制了复合材料在弹道冲击中的能量吸收。因此,研究人员使用棋盘格状聚碳酸酯(PC)薄膜和芳纶平纹织物,研究了采用棋盘格状铺层设计的新型弹道复合材料。研究了棋盘状 PC 薄膜的尺寸和交叉层分布的影响。与全覆盖铺层设计相比,棋盘格状铺层设计能有效提高弹道性能。对于棋盘格形铺层设计的防弹复合材料,在撞击 PC 区域时,防弹性能变化不大,但在撞击芳纶纤维区域时,防弹性能随纤维区域的大小而逐渐增加。间隔交叉层棋盘状 PC 薄膜的防弹性能也随着间隔层数的增加而提高。在撞击 PC 区域时,主要的弹道机制是压缩/剪切和剪切/拉伸破坏;然而,当分层和应力波传播到没有 PC 薄膜的区域时,棋盘式层叠设计允许织物通过拉伸破坏有效吸收能量。在冲击芳纶织物区域时,主要的弹道机制是剪切/拉伸破坏和拉伸破坏。然而,当芳纶织物区域的尺寸不足时,靠近 PC 的区域会限制织物的横向变形,这不利于弹道性能的提高。