今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 4 篇,Composites Science and Technology 1 篇
Stability of tensegrity-inspired structures fabricated through additive manufacturing
Anna Al Sabouni-Zawadzka, Wojciech Gilewski, Rana Nazifi Charandabi, Adam Zawadzki
doi:10.1016/j.compstruct.2024.118377
通过增材制造制造的张拉整体结构的稳定性
This study encompasses experimental and theoretical research on the stability of tensegrity-inspired structures in view of additive manufacturing technology. The aim of the research is to produce a qualitative and quantitative estimation of the post-critical behavior of struts in 3D-printed tensegrity-inspired modules. Presented results of compression tests performed on modules and single struts show that the bars work in the post-critical state before they reach their load bearing capacity. Comparison of theoretical solutions with experimental tests allowed us to conclude that the struts can carry axial loads significantly higher than the limits resulting from the classical Euler theory.
本研究包括增材制造技术下张拉整体结构稳定性的实验和理论研究。该研究的目的是对3d打印张拉整体启发模块中支柱的后临界行为进行定性和定量估计。对模块和单支杆进行的压缩试验结果表明,杆在达到其承载能力之前处于后临界状态。理论解与实验测试的比较使我们得出结论,支撑可以承受的轴向载荷明显高于经典欧拉理论的极限。
Harvesting tacit knowledge for composites workforce development
John Summerscales
doi:10.1016/j.compositesa.2024.108357
为复合材料劳动力开发获取隐性知识
Explicit knowledge can often be shared through textbooks, technical papers, instruction manuals, guides, and videos. It is normally objective, logical and technical. However, tacit (implicit) knowledge is any information or skills that arise from personal and professional experiences. It is often subjective, cognitive and experiential. When an individual leaves an organisation, they can take intellectual property with them that could compromise future operations, unless that knowledge is harvested. This brief review considers how transient knowledge might be retained in an organisation.
显性知识通常可以通过教科书、技术论文、指导手册、指南和视频进行共享。它通常是客观的、合乎逻辑的和技术性的。然而,隐性知识是来自个人和专业经验的任何信息或技能。它通常是主观的、认知的和经验的。当一个人离开一个组织时,他可能会带走知识产权,这可能会影响到未来的运营,除非他能收获这些知识。这篇简短的综述考虑了如何在组织中保留瞬时知识。
Development of the CaCO3-coated passive film on Mg alloy densified by glucose/sodium gluconate via the assistance of ultrasound with a regrowth feature in Portland cement
Ye Wang, Jingfeng Wang, Fusheng Pan
doi:10.1016/j.compositesb.2024.111719
超声辅助下葡萄糖/葡萄糖酸钠致密镁合金caco3包覆钝化膜在硅酸盐水泥中的再生特性研究
To address the limitations of non-dense chemical conversion coatings on Mg alloys, glucose and sodium gluconate were employed to facilitate the creation of dual-layered CaCO3 coated MgO passive layers via ultrasound-assisted chemical conversion. Results indicate that the addition of an appropriate quantity of glucose enhances the corrosion resistance of CaCO3/MgO coatings, whereas excessive glucose compromises coating density. Furthermore, higher concentrations of sodium gluconate contribute to improving coating density. Significantly, the immersion in simulated concrete pore solutions with 0.6M NaCl reveals a re-growth phenomenon instead of corrosion. This observation stems from the increased CaCO3 production, including calcite and aragonite during the immersion process.
为了解决镁合金非致密化学转化涂层的局限性,利用葡萄糖和葡萄糖酸钠通过超声辅助化学转化制备了双层CaCO3涂层MgO被动层。结果表明,添加适量的葡萄糖可以增强CaCO3/MgO涂层的耐腐蚀性,而过量的葡萄糖会降低涂层的密度。此外,较高的葡萄糖酸钠浓度有助于提高涂层密度。值得注意的是,0.6M NaCl浸泡在模拟混凝土孔隙溶液中,出现了再生长现象,而不是腐蚀。这一观察结果源于浸没过程中CaCO3产量的增加,包括方解石和文石。
Semi-destructive Methods for Evaluating the Micro-scale Residual Stresses of Carbon Fiber Reinforced Polymers
Wanying Zhao, Xiang Li, Jinrui Ye, Kai Liu, Xiangyu Xu, Zhanwei Liu
doi:10.1016/j.compositesb.2024.111722
评价碳纤维增强聚合物微尺度残余应力的半破坏性方法
Micro-scale residual stress in carbon fiber reinforced polymers have a significant impact on their mechanical performance. The residual stresses in the carbon fibers were released by micro-slotting and micro-ring-core methods using focused ion beam (FIB). The released deformation fields were captured by cross-gratings and mapped by geometric phase analysis (GPA) and digital image correlation (DIC) methods. The in-plane residual stresses in the carbon fibers were experimentally determined to be -40.5 MPa using elastic constitutive relations, which is consistent with the composites cylinder model. The axial compressive residual stresses in the fibers were found to be greater than -100 MPa. Moreover, the maximum value of residual stress in the polymer matrix was observed at the interface, potentially serving as a crack initiation site.
碳纤维增强聚合物的微尺度残余应力对其力学性能有重要影响。采用聚焦离子束(FIB)微开槽法和微环芯法释放碳纤维中的残余应力。通过交叉光栅捕获释放变形场,并通过几何相位分析(GPA)和数字图像相关(DIC)方法进行映射。利用弹性本构关系确定了碳纤维的面内残余应力为-40.5 MPa,与复合材料圆柱体模型一致。纤维的轴向残余压应力大于-100 MPa。此外,在界面处观察到聚合物基体中残余应力的最大值,这可能是裂纹起裂的部位。
In-situ nanoscale precipitation behavior and strengthening mechanism of WC/IN718 composites manufactured by laser powder bed fusion
Hongmei Zhang, Yujie Wu, Yi Wang, Weiwei Deng, Gang Xu, Kaiyu Luo, Jinzhong Lu
doi:10.1016/j.compositesb.2024.111727
激光粉末床熔覆WC/IN718复合材料的原位纳米析出行为及强化机理
Nickel matrix composites (NMCs) have received much attention as they show excellent high temperature performances, which could meet the demand for hot-end components in severe environments. In this study, the duplex in-situ nanoscale carbides and oxides reinforcing IN718 were fabricated by laser powder bed fusion (LPBF) and addition of submicron WC particles. The microstructural features and mechanical properties were investigated with variations of WC content (0, 0.5, 2, and 4wt.%). The columnar dendrites with strong <001> texture that boundary distributed continuous Laves phase were found in the LPBF-processed IN718. Incorporating WC led to higher laser absorption and processability, whereas it also decreased the anisotropy of the matrix featured by weak texture index. With an optimized content of 2wt.%, the WC was dissolved into W and C atoms under laser irradiation, which promoted the homogeneous precipitation of intergranular cubic (Nb, Ti)C (∼50 nm) and intragranular spherical Al2O3 (∼20 nm). These precipitates would for heterogenous nucleation to refine grains (∼12.6 μm) and bring about high-density dislocations. The yield strength (YS) and ultimate tensile strength (UTS) increased by 28.8% and 26.5%, respectively, while maintaining high elongation compared with reported NMCs, demonstrating a favorable strength-ductility combination. Finally, the mechanism of microstructure evolution and strengthening was elucidated.
镍基复合材料因其优异的高温性能,能够满足恶劣环境下热端部件的需求而备受关注。在本研究中,采用激光粉末床熔合(LPBF)和添加亚微米WC颗粒的方法制备了增强IN718的双相原位纳米碳化物和氧化物。研究了WC含量(0、0.5、2和4wt.%)变化时的微观组织特征和力学性能。在lpbf处理的IN718中发现了具有强<001>织构的柱状枝晶,具有边界分布的连续Laves相。WC的加入提高了激光吸收率和可加工性,同时降低了织构指数较弱的基体的各向异性。优化含量为2wt。%, WC在激光照射下溶解于W和C原子中,促进晶间立方(Nb, Ti)C (~ 50 nm)和晶内球形Al2O3 (~ 20 nm)的均匀析出。这些析出相使晶粒细化(~ 12.6 μm)并产生高密度位错。与已有报道的nmc相比,其屈服强度(YS)和极限抗拉强度(UTS)分别提高了28.8%和26.5%,同时保持了较高的延伸率,表现出良好的强度-塑性组合。最后,对微观组织演化和强化机理进行了探讨。
CNT modified chopped ultra-thin CF/PET tapes reinforced PET thermoplastic composite laminates with elevated interfacial properties and ultra-low porosity
Yang Guang, Cui Jinze, Zhang Simin, Kuang Xingwen, Luo Yutai, Bao Feng, Yu Jiali, Liu Huichao, Zhu Caizhen, Xu Jian
doi:10.1016/j.compositesb.2024.111718
碳纳米管改性短切超薄CF/PET带增强具有高界面性能和超低孔隙率的PET热塑性复合材料层合板
Carbon fiber (CF) reinforced thermoplastic polyethylene terephthalate (PET) laminate composites with light weight, high strength, excellent damage tolerance, and recyclability have garnered increasing attention. However, the weak interface between inert CF and PET resin, as well as the difficulty of impregnating the considerably high melt viscosity of PET matrix into the CF bundles, have impeded further development of the CF/PET composites. To settle the challenge, the chopped ultra-thin CF tapes (thickness of 40 μm and length of 30 mm) reinforced PET composite laminates were prepared by mechanical spreading technology, following with random stacking and molding technology via the plasma treatment and PET/carbon nanotubes (CNT) sizing. As a results, the optimal interlaminar shear strength (ILSS), tensile strength, and Young’s modulus of the chopped ultra-thin CF tapes reinforced PET composites (with 1.0 wt.% CNT) achieved 42.4 MPa, 780.9 MPa, and 47.8 GPa, which increased by 41.9%, 40.7%, and 68.9%, respectively, compared to unmodified CF/PET composites. Especially, the porosity of the composites reached 0.68%, decreased by 84.3%. Therefore, combining the easy infiltrability of chopped ultra-thin CF tapes technology and the multiscale interfacial reinforced strategy (plasma treatment and PET/CNT sizing) is an effective way to reduce the porosity and enhance the mechanical properties of the thermoplastic composites.
碳纤维(CF)增强热塑性聚对苯二甲酸乙二醇酯(PET)层压板复合材料具有重量轻、强度高、耐损伤性好、可回收性好等优点,越来越受到人们的关注。然而,惰性CF和PET树脂之间的弱界面,以及将相当高的熔融粘度的PET基体浸渍到CF束中的困难,阻碍了CF/PET复合材料的进一步发展。为了解决这一难题,采用机械铺层技术制备了厚度为40 μm、长度为30 mm的CF薄带增强PET复合材料层合板,然后通过等离子体处理和PET/碳纳米管(CNT)上浆,采用随机堆叠和成型技术制备了PET复合材料层合板。结果表明,与未改性的CF/PET复合材料相比,剪切超薄CF带增强PET复合材料(含1.0 wt.% CNT)的最佳层间剪切强度(ILSS)、抗拉强度(780.9 MPa)和杨氏模量(47.8 GPa)分别提高了41.9%、40.7%和68.9%。特别是复合材料的孔隙率达到0.68%,降低了84.3%。因此,将剪切超薄CF带的易渗透特性与多尺度界面增强策略(等离子体处理和PET/CNT上浆)相结合,是降低热塑性复合材料孔隙率、提高其力学性能的有效途径。
Novel computational model for the failure analysis of composite pipes under bending
Tianyu Wang, Oleksandr Menshykov, Marina Menshykova
doi:10.1016/j.compscitech.2024.110757
复合材料管道弯曲失效分析的新计算模型
This study presents a novel computational model to investigate the bending behaviour of thin- and thick-walled composite pipes made from fully bonded fibre-reinforced thermoplastic composite materials. The primary objective is to analyse the stress state and predict potential failure modes of these pipes, which have gained significant interest in the oil and gas industry due to their advantageous properties. The developed model is validated through comparisons with finite element analysis and published results, demonstrating its accuracy and adaptability. Utilizing the validated computational model, safety zones for composite pipes with various stacking sequences are established, providing valuable insights into the optimal design of composite pipes under bending loads. Furthermore, the method is employed to determine the maximum bending moment and critical bendable radius of the pipe, revealing the direct correlation between maximum bending moment and bending stiffness, independent of the bending radius. The findings of this study offer practical guidance for the design and optimisation of composite pipes in the oil and gas industry, promoting their adoption as a viable alternative to traditional metal pipes. The developed computational model serves as an efficient and reliable tool for engineers to make informed decisions in the design and selection of advanced composite materials for pipe applications, enabling the optimisation of pipe performance under various bending load scenarios.
本研究提出了一种新的计算模型来研究由全粘合纤维增强热塑性复合材料制成的薄壁和厚壁复合管材的弯曲行为。主要目的是分析这些管道的应力状态并预测其潜在的失效模式,这些管道因其优越的性能而引起了石油和天然气行业的极大兴趣。通过与有限元分析和已发表结果的比较,验证了所建模型的准确性和适应性。利用验证的计算模型,建立了复合材料管道在不同堆叠顺序下的安全区域,为复合材料管道在弯曲载荷下的优化设计提供了有价值的见解。利用该方法确定了管道的最大弯矩和临界弯曲半径,揭示了最大弯矩与弯曲刚度之间的直接关系,而与弯曲半径无关。该研究结果为油气行业复合管道的设计和优化提供了实用指导,促进了复合管道作为传统金属管道的可行替代品的采用。开发的计算模型是工程师在设计和选择先进复合材料时做出明智决策的有效可靠工具,可以优化管道在各种弯曲载荷情况下的性能。