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【新文速递】2024年3月25日复合材料SCI期刊最新文章

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今日更新:Composite Structures 1 篇,Composites Science and Technology 1 篇

Composite Structures

Improving energy absorption and failure characteristic of additively manufactured lattice structures using hollow and curving techniques

Disaya Disayanan, Pattarapong Buntornvorapan, Thammayuth Sukprasertchai, Vitoon Uthaisangsuk

doi:10.1016/j.compstruct.2024.118067

利用空心和弯曲技术改善快速成型晶格结构的能量吸收和失效特性

Strut-based lattice structures of various types exhibited a common critical issue, namely, high tensile stress concentration occurred at node-to-strut sites, which often led to lowered energy absorbability as compared to triply periodic minimal surfaces structures. Therefore, this work aimed for improving the Octet-truss structure by a combined technique using hollow core and varying cross-section ratio. Firstly, test specimens were fabricated using a stereo-lithography based additive manufacturing of photopolymer hard resin. Elastic-plastic properties and damage criterion of the used polymer were experimentally determined and applied for finite element models. Validation by compressive tests of lattice samples showed deviations of stress–strain responses less than 12%, in which local deformation and subsequent damages were fairly predicted. Afterwards, finite element simulations of designed lattice structures subjected to compressive, combined shear, shear and tensile loads were performed and obtained stress–strain characteristics including total absorbed energies and deformation behaviors were studied. Under uniaxial compression and combined shear loads, modified Octet-truss structures exhibited considerable increases of energy absorptions up to 173% and 116%, respectively, and stress–strain responses were more stable. On the other hand, by tension mode peak stresses and elongations could be enhanced about 41% and 11%, accordingly. The improved performances of proposed strut-based structures were comparable to those of triply periodic minimal surfaces diamond structure. This was due to that local stress distributions in the structure became more uniform and previously dominated tensile stresses were switched to compressive stresses. Therefore, occurrences of shear bands and plastic hinges could be effectively inhibited.

与三周期最小表面结构相比,基于支柱的各种类型的晶格结构表现出一个共同的关键问题,即在节点到支柱的位置出现高拉伸应力集中,这往往会降低能量吸收能力。因此,这项工作旨在通过使用空心芯材和不同截面比的组合技术来改进 Octet 桁架结构。首先,使用基于立体光刻技术的光聚合物硬树脂增材制造技术制作了测试试样。通过实验确定了所用聚合物的弹塑性能和损伤准则,并将其应用于有限元模型。通过对晶格样品进行压缩试验验证,结果表明应力-应变响应的偏差小于 12%,其中局部变形和随后的损伤得到了很好的预测。随后,对受到压缩、联合剪切、剪切和拉伸载荷的设计晶格结构进行了有限元模拟,并研究了所获得的应力应变特性,包括总吸收能量和变形行为。在单轴压缩荷载和组合剪切荷载作用下,改进型八叉桁架结构的能量吸收率显著提高,分别达到 173% 和 116%,应力-应变响应也更加稳定。另一方面,在拉伸模式下,峰值应力和伸长率分别提高了约 41% 和 11%。所提出的支柱型结构的性能改善程度与三周期最小表面金刚石结构相当。这是因为结构中的局部应力分布变得更加均匀,以前占主导地位的拉应力转变为压应力。因此,剪切带和塑性铰的出现可以得到有效抑制。


Composites Science and Technology

Sm2O3 micro-plates/B4C/HDPE composite containing high specific surface area fillers for neutron and gamma-ray complex radiation shielding

Zhipeng Huo, Yidong Lu, Hong Zhang, Guoqiang Zhong

doi:10.1016/j.compscitech.2024.110567

 

含有高比表面积填料的 Sm2O3 微板/B4C/高密度聚乙烯复合材料,用于中子和伽马射线复合辐射屏蔽

In this study, a series of Sm2O3 micro-plates/B4C/HDPE composites composed of synthesized Sm2O3 fillers (Sm2O3 micro-plates) are prepared for shielding neutron and gamma radiation. The influence of micromorphology of Sm2O3 fillers on neutron and gamma radiation shielding properties of composites is investigated in detail. The XRD pattern reveals that the phase of synthetic Sm2O3 is cubic crystal systems, body-centered cubic lattices, and its space group is Ia3¯(206). SEM images and BET analyses reveal that the micromorphology of synthesized Sm2O3 is micro-plates. The BET-specific surface area of the Sm2O3 fillers is increased with addition of urea content. The differential scanning calorimetry (DSC) curves reveal that Sm2O3 fillers increase the melting temperature of the composites, which is up to 138.6 °C. The thermogravimetric analysis (TGA) results reveal that the initial thermal degradation temperatures of the composites are all above 440 °C. The neutron and gamma radiation shielding tests show that Sm2O3 fillers with high BET-specific surface area (8.20 m2/g) and uniform size improve the neutron and gamma shielding rate of composites. A superior composite containing 10 wt% Sm2O3 (R = 1:25, R value represents the molar ratio of rare earth elements to urea)/20 wt% B4C/70 wt% HDPE has a neutron radiation shielding rate of 98.7% with a thickness of 15 cm under the 252Cf neutron source and a gamma radiation shielding rate of 72.1% with a thickness of 15 cm under 137Cs gamma source. And these lead-free and environment-friendly composites can be widely used in the neutron and gamma complex radiation fields.

本研究制备了一系列由合成 Sm2O3 填料组成的 Sm2O3 微板/B4C/HDPE 复合材料(Sm2O3 微板),用于屏蔽中子和伽马辐射。详细研究了 Sm2O3 填料的微观形貌对复合材料中子和伽马辐射屏蔽性能的影响。XRD 图谱显示,合成的 Sm2O3 为立方晶系,体心立方晶格,空间群为 Ia3¯(206)。扫描电镜图像和 BET 分析表明,合成 Sm2O3 的微观形态为微板状。Sm2O3 填料的 BET 比表面积随着尿素含量的增加而增大。差示扫描量热曲线(DSC)显示,Sm2O3 填料提高了复合材料的熔化温度,最高可达 138.6 ℃。热重分析(TGA)结果表明,复合材料的初始热降解温度均高于 440 ℃。中子和伽马辐射屏蔽试验表明,具有高 BET 比表面积(8.20 m2/g)和均匀尺寸的 Sm2O3 填料可提高复合材料的中子和伽马屏蔽率。含有 10 wt% Sm2O3(R = 1:25,R 值代表稀土元素与尿素的摩尔比)/20 wt% B4C/70 wt% HDPE 的优质复合材料在 252Cf 中子源下,厚度为 15 cm 的中子辐射屏蔽率为 98.7%;在 137Cs 伽马源下,厚度为 15 cm 的伽马辐射屏蔽率为 72.1%。这些无铅环保型复合材料可广泛应用于中子和伽马复合辐射领域。



来源:复合材料力学仿真Composites FEM
ACTAdditiveSystemDeform复合材料增材ADS材料试验
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首次发布时间:2024-11-13
最近编辑:9天前
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【新文速递】2024年3月27日复合材料SCI期刊最新文章

今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Science and Technology 1 篇Composite StructuresStiffness-driven design and optimization of a 3D-printed composite prosthetic foot: A beam finite Element-Based frameworkAbdel Rahman N. Althahabi, Luca M. Martulli, Andrea Sorrentino, Marino Lavorgna, Emanuele Gruppioni, Andrea Bernasconidoi:10.1016/j.compstruct.2024.118053三维打印复合材料义足的刚度驱动设计与优化:基于梁有限元的框架Composite foot prostheses are traditionally produced via lamination, a process that grants high structural efficiency. However, it is an expensive and time-consuming process. Production rate and customizability are thus limited. Additive manufacturing of composites can be a potential solution to these limitations. This work presents a tool to design and optimize Continuous Fiber-Reinforced Additively Manufactured (CFRAM) prosthetic feet using beam Finite Element (FE) modeling. This optimization tool was developed for weight minimization and obtaining a CFRAM prosthesis design matching up to three static stiffness parameters. The design variables were defined through parametrizing the geometry of the prosthesis designed and using the composite structure parameters. Thanks to the versatility of the tool, solutions to multiple optimization and design cases were used to assess different design concepts, such as the shape of the prosthesis (C-shape or J-shape). Also, the tool successfully duplicated the stiffness characteristics of an assumed laminated prosthesis. Finally, the sources of inaccuracy associated with the beam FE modeling approach were identified through a comparison with plane stress FE analysis.复合材料脚假肢传统上是通过层压工艺生产的,这种工艺具有很高的结构效率。然而,这种工艺既昂贵又耗时。因此,生产率和可定制性受到限制。复合材料的增材制造是解决这些限制的潜在方法。这项工作介绍了一种利用梁有限元(FE)建模设计和优化连续纤维增强增材制造(CFRAM)义足的工具。开发该优化工具的目的是使重量最小化,并获得与三个静态刚度参数相匹配的 CFRAM 假肢设计。设计变量是通过设计假肢的几何参数和复合结构参数来定义的。得益于该工具的多功能性,多个优化和设计案例的解决方案被用于评估不同的设计理念,如假体形状(C 形或 J 形)。此外,该工具还成功复 制了假定层叠假体的刚度特征。最后,通过与平面应力 FE 分析的比较,确定了与梁 FE 建模方法相关的不准确性来源。Composites Part A: Applied Science and ManufacturingIn-situ solid-state deformation-driven rapid reaction towards higher strength-ductility Al-CuO compositesDongxin Mao, Xiaotian Ma, Yuming Xie, Xiangchen Meng, Naijie Wang, Zeyu Zhang, Xiuwen Sun, Yongxian Huangdoi:10.1016/j.compositesa.2024.108174 原位固态变形驱动快速反应,实现更高强度和电导率的 Al-CuO 复合材料The strength-ductility dilemma of metallic matrix composites is mainly attributed to the mismatched phase/matrix interfaces, which induce stress concentration as dislocation piles up. Here, coherent nano-Al2O3 phases were in-situ formed in Al-CuO composites via rapid diffusion of neoteric deformation-driven metallurgy. The complex dislocation configuration was also promoted to induce the formation of about 14.5 % incoherent twin boundaries. The mean free path for dislocation movements was expanded, as dislocations could cut through the coherent nano-Al2O3 phases and interact with the incoherent twin boundaries without piled-up dislocations. The yield strength and elongation of the strength-ductility synergy Al-5CuO composites were 201 ± 14 MPa and 16.1 ± 0.5 %, indicating that in-situ Al2O3-Al coherent interface and incoherent twin boundaries exert remarkable ability of dislocation transmission.金属基复合材料的强度-电导率困境主要归因于不匹配的相/基界面,这种界面会随着位错的堆积而导致应力集中。在这里,通过新形变驱动冶金的快速扩散,在 Al-CuO 复合材料中就地形成了相干的纳米 Al2O3 相。复杂的位错配置也促进了约14.5%的非相干孪晶边界的形成。位错运动的平均自由路径扩大了,因为位错可以穿过相干的纳米 Al2O3 相,并与不相干的孪生边界相互作用,而不会堆积位错。强度-电导率协同效应 Al-5CuO 复合材料的屈服强度和伸长率分别为 201 ± 14 MPa 和 16.1 ± 0.5 %,表明原位 Al2O3-Al 相干界面和非相干孪晶边界具有显著的位错传输能力。Composites Science and TechnologyIn-situ exfoliation of hexagonal boron nitride during the forced flow of highly elastic polylactide to fabricate electrospun fibrous film with high thermal conductivity and low dielectric lossRuixue Wu, Xudong Song, Yuan Ji, Hong Wu, Shaoyun Guo, Jianhui Qiudoi:10.1016/j.compscitech.2024.110573 在高弹性聚乳酸的强制流动过程中原位剥离六方氮化硼,以制造具有高热导率和低介电损耗的电纺纤维膜Boron nitride nanosheets (BNNS) have promising applications in thermal management materials, due to their high thermal conductivity and low dielectric loss. However, it is still challenging to fabricate BNNS with large lateral size and structural integrity via solvent-free methods. Here, we report a novel processing method for in-situ exfoliation of hexagonal boron nitride (h-BN) to fabricate BNNS with an average lateral size of 1.45 μm, average thickness of 4.88 nm and few lattice defects during the forced flow of polylactide (PLA) in a highly elastic state. We further fabricate flexible and bio-degradable PLA/BNNS electrospun fibrous film for electronic devices to replace petroleum-based composites. The PLA/BNNS fibrous film exhibits an in-plane thermal conductivity of 4.9 W/(m·K) at the BNNS loading of 20 wt%. Moreover, the fibrous film also has a low dielectric loss (0.007 at 1 kHz) and good electrical insulation. The in-situ exfoliation strategy is simple, economical and environmentally friendly, providing an effective route to design thermal management materials with high thermal conductivity and low dielectric loss in the future of electronic devices.氮化硼纳米片(BNNS)具有高热导率和低介电损耗的特点,因此在热管理材料领域有着广阔的应用前景。然而,通过无溶剂方法制造具有大横向尺寸和结构完整性的 BNNS 仍然具有挑战性。在此,我们报告了一种原位剥离六方氮化硼(h-BN)的新型加工方法,在高弹性聚乳酸(PLA)的强制流动过程中,制备出平均横向尺寸为 1.45 μm、平均厚度为 4.88 nm 且晶格缺陷极少的 BNNS。我们进一步制备了柔韧且可生物降解的聚乳酸/BNNS电纺纤维膜,用于电子设备以取代石油基复合材料。当 BNNS 含量为 20 wt% 时,聚乳酸/BNNS 纤维薄膜的面内导热系数为 4.9 W/(m-K)。此外,该纤维膜还具有较低的介电损耗(1 kHz 时为 0.007)和良好的电绝缘性。这种原位剥离策略简单、经济、环保,为未来电子设备设计具有高热导率和低介电损耗的热管理材料提供了一条有效途径。来源:复合材料力学仿真Composites FEM

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