今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 6 篇,Composites Part B: Engineering 1 篇
Fracture mechanics investigation for 2D orthotropic materials by using ordinary state-based peridynamics
Hanlin Wang, Satoyuki Tanaka, Selda Oterkus, Erkan Oterkus
doi:10.1016/j.compstruct.2023.117757
利用基于普通状态的周动力学对二维正交材料进行断裂力学研究
Fracture behaviours of orthotropic plates are studied by using ordinary state-based peridynamic (OSPD) theory. Based on OSPD, a novel nonlocal formulation of interaction integral is proposed by considering the material orthogonality for the fracture parameter evaluation. By employing peridynamic differential operator, the partial differential terms in the formulation can be transformed into corresponding spatial integral form, which contributes to the calculations of stress intensity factors within the framework of OSPD. It has built up a relationship between classical theory and peridynamic theory. Static and dynamic fracture parameters are carefully evaluated. The crack propagation directions are predicted by prototype microelastic brittle (PMB) criterion in OSPD and maximum circumferential stress (MCS) criterion in classical theory. Several pre-cracked plates with orthotropic material are examined, and results are validated by comparing against the reference solutions. The relationship between fiber orientation and crack inclined angle are also examined. Meanwhile, the crack inclination determined by PMB criterion and MCS criterion are compared and discussed. Accuracy of the peridynamic orthotropic model and proposed nonlocal interaction integral are discussed in detail.
利用基于普通状态的周动力学(OSPD)理论研究了各向同性板的断裂行为。在 OSPD 的基础上,考虑到材料的正交性,提出了一种新的非局部相互作用积分公式,用于断裂参数评估。通过使用周动态微分算子,可将公式中的偏微分项转化为相应的空间积分形式,从而有助于在 OSPD 框架内计算应力强度因子。它建立了经典理论与周动态理论之间的关系。对静态和动态断裂参数进行了仔细评估。通过 OSPD 中的原型微弹性脆性(PMB)准则和经典理论中的最大圆周应力(MCS)准则预测了裂纹的扩展方向。研究了几种具有正交性材料的预裂纹板材,并通过与参考解的比较验证了结果。此外,还研究了纤维取向与裂纹倾斜角之间的关系。同时,对 PMB 准则和 MCS 准则确定的裂纹倾角进行了比较和讨论。详细讨论了围动力正交模型和所提出的非局部相互作用积分的准确性。
Applying an extrapolation approach to prevent the thermal degradation of CFRPs at extreme heating rates - The laser processing of CF/PEEK
Dimitrios Gaitanelis, Chris Worrall, Mihalis Kazilas
doi:10.1016/j.compositesa.2023.107938
采用外推法防止 CFRP 在极端加热速率下发生热降解 - CF/PEEK 的激光加工
This study proposes a coupled thermal-chemical numerical model for preventing the thermal degradation of carbon fibre (CF) reinforced polymers at extreme heating rates. Its applicability is demonstrated in a laser-heating case study of CF-reinforced poly-ether-ether-ketone (CF/PEEK). The kinetic parameters of the PEEK matrix, derived from thermogravimetry at conventional heating rates, are introduced in the model and an extrapolation approach is applied to investigate the laser heating of CF/PEEK. The results show that the model captures the heating rate effect on the material’s decomposition, and it is used to identify the optimum laser parameters that prevent the thermal degradation of the PEEK matrix. Likewise, a multi-technique experimental investigation takes place to identify the processing conditions that first trigger the thermal degradation mechanisms of CF/PEEK in the examined laser-heating case study. Interestingly, a good agreement is found between the experimental and numerical results which validates the model and the applied extrapolation approach.
本研究提出了一种热化学耦合数值模型,用于防止碳纤维(CF)增强聚合物在极端加热速率下发生热降解。通过对碳纤维增强聚醚醚酮(CF/PEEK)的激光加热案例研究,证明了该模型的适用性。模型中引入了根据传统加热速率下的热重分析得出的 PEEK 基体动力学参数,并采用外推法研究了 CF/PEEK 的激光加热。结果表明,该模型捕捉到了加热速率对材料分解的影响,并可用于确定防止 PEEK 基体热降解的最佳激光参数。同样,在所研究的激光加热案例中,还进行了一项多技术实验调查,以确定首先引发 CF/PEEK 热降解机制的加工条件。有趣的是,实验结果和数值结果之间存在良好的一致性,从而验证了模型和应用的外推法。
From 2D graphene and MXene nanolayers to 3D biomimetic porous composite aerogels for electromagnetic interference shielding
Qilei Wu, Zhihui Zeng, Long Xiao
doi:10.1016/j.compositesa.2023.107939
从二维石墨烯和 MXene 纳米层到用于电磁干扰屏蔽的三维仿生多孔复合气凝胶
The need for high-performance electromagnetic interference (EMI) shielding materials with low density, high mechanical strength, and effective EMI shielding capabilities is paramount in addressing the growing issue of electromagnetic pollution. Three-dimensional aerogels, constructed from two-dimensional transition metal carbides and/or nitrides (MXenes), or graphene nanosheets, exhibit immense potential in EMI shielding. These materials are characterized by their lightweight nature, remarkable mechanical properties, excellent conductivity, and large specific surface area, with the added advantage of a biomimetic aligned porous structure that significantly enhances EMI shielding performance. This review highlights recent studies focusing on the design of biomimetic unidirectional pore structures in MXene or graphene-based composite aerogels, advancing the development of lightweight EMI shields. We provide a comprehensive summary of the preparation methods, current progress, ongoing challenges, and future prospects for MXene and graphene-based aerogels with aligned porous structures. This serves as a valuable guideline for future development of high-performance aerogel-based EMI shields.
在解决日益严重的电磁污染问题时,最需要的是具有低密度、高机械强度和有效电磁干扰屏蔽能力的高性能电磁干扰(EMI)屏蔽材料。由二维过渡金属碳化物和/或氮化物(MXenes)或石墨烯纳米片构成的三维气凝胶在电磁干扰屏蔽方面具有巨大的潜力。这些材料的特点是重量轻、机械性能卓越、导电性好、比表面积大,而且具有仿生物排列的多孔结构,可显著提高电磁干扰屏蔽性能。本综述重点介绍了近期关于在 MXene 或石墨烯基复合气凝胶中设计仿生物单向孔结构的研究,这些研究推动了轻质 EMI 屏蔽的发展。我们全面总结了具有对齐多孔结构的 MXene 和石墨烯基气凝胶的制备方法、当前进展、持续挑战和未来前景。这为今后开发基于气凝胶的高性能 EMI 屏蔽板提供了宝贵的指导。
Laser Additive Manufacturing of Ceramic Reinforced Titanium Matrix Composites: A Review of Microstructure, Properties, Auxiliary Processes, and Simulations
Yuzhou Zeng, Jiandong Wang, Xuanrui Liu, Yu Xue, Lang Tang, Yunxiang Tong, Fengchun Jiang
doi:10.1016/j.compositesa.2023.107941
陶瓷增强钛基复合材料的激光增材制造:微观结构、性能、辅助工艺和模拟综述
The satisfactory integrated performance of titanium matrix composites (TMCs) has rendered them promising candidates in significant industries including aerospace and biomedicine. Laser additive manufacturing (LAM) technology has facilitated the fabrication of titanium-based materials in a more convenient and efficient manner. Microstructure and properties of LAM-fabricated TMCs are influenced by diverse variables, such as process and powder parameters. To enhance the composites, various reinforcement materials have been employed. However, defects and undesired microstructure frequently cause suboptimal properties. Recent research has explored the possibility of enhancing material properties by combining LAM with auxiliary treatment processes. Furthermore, numerical simulations have been employed to optimize the LAM process of TMCs, elucidate mechanisms, and make predictions. This article provides a comprehensive review of the current research on TMCs produced by LAM techniques, highlighting their potential for future development. The technological development and practical application of LAM-fabricated TMCs can be promoted potentially through suggested research endeavors.
钛基复合材料(TMC)令人满意的综合性能使其在航空航天和生物医学等重要行业中大有可为。激光增材制造(LAM)技术以更便捷、更高效的方式促进了钛基材料的制造。LAM 制成的钛基复合材料的微观结构和性能受到工艺和粉末参数等多种变量的影响。为了提高复合材料的性能,人们采用了各种增强材料。然而,缺陷和不理想的微观结构经常会导致性能不理想。最近的研究探索了通过将 LAM 与辅助处理工艺相结合来增强材料性能的可能性。此外,还利用数值模拟来优化 TMC 的 LAM 工艺、阐明机理并进行预测。本文全面综述了目前有关 LAM 技术生产 TMC 的研究,并强调了其未来的发展潜力。通过建议的研究工作,可促进 LAM 制造 TMC 的技术发展和实际应用。
Laser-Induced Selective Metallization of Epoxy Resin: Preparing Ultra-Thin and Ultra-Light Motors
Feifan Yu, Haoran Xu, Tao Zhou
doi:10.1016/j.compositesa.2023.107946
激光诱导环氧树脂选择性金属化:制备超薄超轻电机
Epoxy composites with an excellent laser-induced selective metallization (LISM) capability were designed and prepared by combining the bisphenol A-type epoxy resin (EP) with laser sensitizers (CuO·Cr2O3 and ATO). The dispersion of laser sensitizers in epoxy molding compound (EMC), as well as their influence on the curing reaction and mechanical strength of epoxy composites, was investigated. We confirmed that CuO·Cr2O3 is the more suitable laser sensitizer for epoxy composites. The tensile strength of EP/CuO·Cr2O3 composite was 51.6 MPa, and the resistance of the obtained copper layers was 0.2 Ω. Moreover, this composite can be used to produce ultrafine copper wires and perforated circuits using LISM technology. Inspired by its excellent LISM performance, an ultra-thin and ultra-light motor was designed and fabricated. The weight of the entire motor was only 28.8 g and a thickness of 6 mm due to the integration of the stator frame and stator windings.
通过将双酚 A 型环氧树脂(EP)与激光敏化剂(CuO-Cr2O3 和 ATO)相结合,设计并制备了具有优异激光诱导选择性金属化(LISM)能力的环氧复合材料。研究了激光敏化剂在环氧模塑料(EMC)中的分散情况及其对环氧复合材料固化反应和机械强度的影响。我们证实 CuO-Cr2O3 是更适合环氧树脂复合材料的激光敏化剂。EP/CuO-Cr2O3 复合材料的拉伸强度为 51.6 MPa,铜层的电阻为 0.2 Ω。此外,这种复合材料还可用于利用 LISM 技术生产超细铜线和穿孔电路。受其出色的 LISM 性能启发,我们设计并制造出了超薄超轻电机。由于定子框架和定子绕组的集成,整个电机的重量仅为 28.8 克,厚度仅为 6 毫米。
Reinforcement Effects of Graphite Fluoride on Breakdown Voltage Rating and Pyro-Resistive Properties of Carbon Black/Poly (vinylidene fluoride) Composites
Yinghao Qi, Chuanchuan Dai, Jiaqi Gao, Boyuan Gou, Siwen Bi, Peng Yu, Xuhuang Chen
doi:10.1016/j.compositesa.2023.107947
氟化石墨对炭黑/聚(偏氟乙烯)复合材料击穿电压等级和耐热性能的增强效果
The utilization of conductive polymer-matrix composites (CPCs) with a high concentration of filler as an overcurrent protection device can reduce operational load and improves circuit stability. However, limitations such as reduced positive temperature coefficient (PTC) intensity and inferior voltage breakdown strength hinder its development. To overcome this, the study investigates the integration of graphite fluoride into carbon black (CB)/Poly (vinylidene fluoride) (PVDF) composites. The graphite fluoride-doped CPCs demonstrate outstanding voltage resistance, PTC intensity, and electrical properties, which can be ascribed to the heightened compatibility and adhesion between CB and PVDF, resulting in diminished migration and agglomeration of conductive fillers during current shock and thermal conditions. Graphite fluoride also acts as a shield, counteracting the negative effects of electrical, chemical, and thermal breakdown failures, thus inhibiting PVDF degradation during current impact. Overall, this approach significantly enhances the voltage withstand capability of overcurrent protection devices under current saturation conditions.
利用含有高浓度填料的导电聚合物基复合材料(CPC)作为过流保护装置,可以降低工作负载并提高电路稳定性。然而,正温度系数(PTC)强度降低和电压击穿强度低等局限性阻碍了其发展。为了克服这一问题,本研究探讨了将氟化石墨融入炭黑(CB)/聚偏二氟乙烯(PVDF)复合材料的问题。掺杂氟化石墨的 CPC 具有出色的耐压性、PTC 强度和电气性能,这可归因于炭黑与 PVDF 之间的相容性和粘附性增强,从而减少了导电填料在电流冲击和热条件下的迁移和聚集。氟化石墨还能起到屏蔽作用,抵消电气、化学和热击穿故障的负面影响,从而抑制 PVDF 在电流冲击下的降解。总之,这种方法大大提高了过流保护装置在电流饱和状态下的耐压能力。
Analytical fracture toughness model for multiphase epoxy matrices modified by thermoplastic and carbon nanotube/thermoplastic
Hong Ma, Peihao Geng, Tingyu Xu, Aswani Kumar Bandaru, Ali Aravand, Brian G. Falzon
doi:10.1016/j.compositesa.2023.107948
热塑性塑料和碳纳米管/热塑性塑料改性多相环氧基质的断裂韧性分析模型
The introduction of a toughener is considered one of the most effective approaches to address the brittleness of epoxy resins. This paper introduces an analytical model for investigating the Mode-I fracture toughness of modified epoxy resins by including a phase-separating thermoplastic (TP) polymer, polyetherimide (PEI), and the combination of PEI and carbon nanotubes (CNTs). The fracture energy contributions from different toughening mechanisms, identified by the fractographical studies of the modified epoxy resins, were calculated, in which the energy contribution from TP deformation was obtained by molecular dynamics model simulation. The developed fracture toughness model showed satisfactory agreement with the experimental data. In the TP/epoxy binary system, the increase in TP content from 5 to 20 wt.% resulted in a rise in the contribution of TP deformation (crack bridging) leading to a commensurate increase in fracture toughness from 33% to 70%. This transformation established TP deformation as the dominant mechanism for crack energy dissipation. In the CNT/TP/epoxy ternary system, from the model, the observed synergy in toughness was attributed to the improved dispersion of nanotubes. The developed analytical model may be used to formulate multiphase toughened resin matrices for optimal fracture toughness.
引入增韧剂被认为是解决环氧树脂脆性的最有效方法之一。本文介绍了一种分析模型,通过加入相分离热塑性(TP)聚合物、聚醚酰亚胺(PEI)以及 PEI 与碳纳米管(CNT)的组合,研究改性环氧树脂的模态 I 断裂韧性。通过对改性环氧树脂进行断裂力学研究,计算了不同增韧机制的断裂能量贡献,其中 TP 变形的能量贡献是通过分子动力学模型模拟获得的。所建立的断裂韧性模型与实验数据的一致性令人满意。在 TP/epoxy 二元体系中,TP 含量从 5 wt.% 增加到 20 wt.%,导致 TP 变形(裂纹桥接)的贡献增加,断裂韧性也相应从 33% 增加到 70%。这种转变确定了 TP 变形是裂纹能量耗散的主要机制。在 CNT/TP/epoxy 三元体系中,从模型中观察到的韧性协同作用归因于纳米管分散性的改善。所开发的分析模型可用于配制多相增韧树脂基体,以获得最佳断裂韧性。
Thermoforming of partially biodegradable hybrid thermoplastic composites for bone plate applications
Ho-Seok Lee, Seung-Hwan Chang
doi:10.1016/j.compositesb.2023.111123
用于骨板的部分生物可降解混合热塑性复合材料的热成型
This study introduces a partially biodegradable composite of carbon fibre/Nylon and Magnesium alloy (Mg) wire/polylactic acid (PLA) for bone fracture healing, focusing on its mechanical properties, with Young's modulus, flexural strength, and interlaminar shear strength investigated under different forming conditions. The Mg wires were subjected to mechanical and chemical treatments (with 80 and 220 grit sandpapers and phytic acid) to improve mechanical performance. Optimal treatment conditions were determined, and material test results were compared with microscopic observations. Using the recommended forming conditions, a hybrid composite bone plate was thermoformed for potential medical use.
本研究介绍了一种部分可生物降解的碳纤维/尼龙和镁合金(Mg)丝/聚乳酸(PLA)复合材料,用于骨骨折愈合,重点研究其机械性能,包括不同成型条件下的杨氏模量、抗弯强度和层间剪切强度。对镁丝进行了机械和化学处理(使用 80 和 220 号砂纸和植酸),以改善其机械性能。确定了最佳处理条件,并将材料测试结果与显微观察结果进行了比较。利用推荐的成型条件,对混合复合骨板进行了热成型,以用于潜在的医疗用途。