今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 3 篇
Additively-manufactured gradient porous bio-scaffolds: Permeability, cytocompatibility and mechanical properties
Yong Xu, Shuangjun Zhang, Wenhao Ding, Haocheng Du, Mengqi Li, Zonghan Li, Meigui Chen
doi:10.1016/j.compstruct.2024.118021
添加式制造的梯度多孔生物支架:渗透性、细胞相容性和机械性能
The additive manufacturing technology enables the customization of artificial bone scaffolds, especially those with internal gradient porous structures (GS). It is of great significance to study the correlation between parametric design of GS and its properties. In this study, GS scaffolds were obtained by triply periodic minimal surfaces (TPMS) parametric design and fabricated by selective laser sintering. The stress distribution and permeability of GS scaffolds were elucidated by a combination of numerical simulation and experimental testing. Experimental tests indicated that the pore size of GS scaffold is in the range of 570 ∼ 1440 μm, corresponding to the average compressive strength of 3.0 ∼ 9.3 MPa, respectively. The test permeability of GS scaffolds ranged from 1.241 × 10-9 to 2.231 × 10-9 m2, all within the range of human bones (2.56 × 10-11 to 7.43 × 10-8 m2). Moreover, in vitro biomineralization and biological testing of GS scaffolds showed excellent calcium-phosphorus formation induction and biocompatibility. In summary, GS scaffold successfully realizes flexible control of structural parameters, especially GP-type scaffolds with radial gradient porous structures exhibit mechanical properties and permeability comparable to natural bone tissue, and even effectively regulate cell behavior. Therefore, the GS scaffolds proposed in this work is expected to exhibit great application potential in orthopedic implants.
增材制造技术实现了人工骨支架的定制,尤其是具有内部梯度多孔结构(GS)的人工骨支架。研究GS的参数设计与其特性之间的相关性具有重要意义。本研究通过三重周期性最小表面(TPMS)参数化设计获得了GS支架,并通过选择性激光烧结制造了GS支架。通过数值模拟和实验测试相结合的方法,阐明了 GS 支架的应力分布和渗透性。实验测试表明,GS 支架的孔径范围为 570 ∼ 1440 μm,对应的平均抗压强度分别为 3.0 ∼ 9.3 MPa。GS 支架的测试渗透率范围为 1.241 × 10-9 至 2.231 × 10-9 m2,均在人体骨骼(2.56 × 10-11 至 7.43 × 10-8 m2)的范围内。此外,GS 支架的体外生物矿化和生物测试表明其具有良好的钙磷形成诱导性和生物相容性。综上所述,GS支架成功实现了对结构参数的灵活控制,尤其是具有径向梯度多孔结构的GP型支架表现出与天然骨组织相当的力学性能和渗透性,甚至能有效调节细胞行为。因此,本研究提出的 GS 型支架有望在骨科植入物中展现出巨大的应用潜力。
Experimental process characterisation for High-Volume compression moulding of Hybrid-Architecture composites
Hao Yuan, Muhammad Khan, Ton Peijs, Connie Qian
doi:10.1016/j.compositesa.2024.108137
混合结构复合材料大容量压缩成型的实验工艺特征描述
Compression moulding of woven fabric prepreg and sheet moulding compound (SMC) in a single-shot process combines the superior mechanical properties of continuous fibre composites and the high design flexibility of discontinuous fibre composites. This experimental study presents insights into the moulding characteristics of prepreg and SMC and explores the interaction between these two materials during manufacturing of hybrid-architecture composites. All tests were performed under typical compression moulding conditions using a squeeze flow testing rig. The response of each material was interpreted through proposed material models applied to the data acquired from single architecture tests. Critical interaction mechanisms were identified from hybrid architecture tests, alongside some additional deformation mechanisms, such a high level of in-plane fibre tow deformation not observed in single-architecture tests. Novel experimental methods were also introduced to quantify the change in meso-scale fibre architecture in the prepreg induced by the flow of SMC. The outcomes of this study not only shed light on the essential interaction mechanisms of hybrid-architecture composites but also provide valuable insights into deformation mechanisms not apparent in isolated material studies. Ultimately, these findings will facilitate the future development of a numerical simulation model for hybrid moulding processes.
编织物预浸料和片状模塑料(SMC)的压缩模塑一次成型工艺结合了连续纤维复合材料的优异机械性能和非连续纤维复合材料的高设计灵活性。本实验研究深入探讨了预浸料和 SMC 的成型特性,并探讨了这两种材料在制造混合结构复合材料过程中的相互作用。所有测试都是在典型的压缩成型条件下使用挤压流动试验台进行的。每种材料的响应都通过应用于单一结构测试数据的材料模型进行解释。从混合结构测试中确定了关键的相互作用机制,以及一些额外的变形机制,如单一结构测试中未观察到的高水平面内纤维束变形。此外,还引入了新的实验方法来量化 SMC 流动引起的预浸料中中尺度纤维结构的变化。这项研究的成果不仅揭示了混合结构复合材料的基本相互作用机制,还为孤立材料研究中不明显的变形机制提供了宝贵的见解。最终,这些发现将有助于未来混合成型工艺数值模拟模型的开发。
A simple stress-based failure criterion for predicting unfolding failure
S. Bushpalli, P. Zumaquero, B. López-Romano, E. Graciani
doi:10.1016/j.compositesa.2024.108139
基于应力的简单失效标准,用于预测展开失效
Corners of highly curved composite laminates experience unfolding failure when they are loaded under opening bending moments. This work provides a comprehensive experimental test campaign and a detailed stress analysis to gain insight into the different failure mechanisms occurring in curved CFRP laminates made from three different thermoset materials. Two distinct failure mechanisms are observed: firstly, traditional unfolding failure, occurring in unidirectional curved composite laminates exhibiting pure interlaminar delamination associated to the maximum interlaminar stresses in the curved region and, secondly, induced unfolding failure occurring in multi-directional curved composite laminates, where the failure is assumed to be originated from intralaminar matrix cracks which, under the presence of high interlaminar stresses, further propagate as an interlaminar delamination. A simple stress-based failure criterion is proposed to predict the unfolding failure load which provides a fairly good agreement with the experimental results in all cases.
当高度弯曲的复合材料层压板的角部在开口弯矩作用下受力时,会出现展开失效。这项研究提供了全面的实验测试活动和详细的应力分析,以深入了解由三种不同热固性材料制成的弯曲 CFRP 层压板的不同失效机理。观察到两种不同的失效机制:第一种是传统的展开失效,发生在单向弯曲复合材料层压板中,表现出与弯曲区域最大层间应力相关的纯层间分层;第二种是诱导展开失效,发生在多向弯曲复合材料层压板中,假定失效源于层内基体裂缝,在高层间应力作用下,裂缝进一步扩展为层间分层。我们提出了一个简单的基于应力的失效准则来预测展开失效载荷,该准则在所有情况下都与实验结果相当吻合。
Simultaneously enhancing strength and ductility of coarse grain Cu–Al alloy via a macro dual-cable structure
Kaixuan Zhou, Yonghao Zhao, Qingzhong Mao, Ruisheng Zhang, Shunqiang Li, Guosheng Sun, Hongzhen Dong, Lei Gu, Jizi Liu
doi:10.1016/j.compositesb.2024.111371
通过宏观双缆结构同时提高粗晶粒铜铝合金的强度和延展性
The trade-off relationship of strength and ductility of metals leads to a strength increase accompanied by a ductility decrease. In the past two decades, despite significant efforts to increase strength while minimizing the ductility loss by tailoring microstructures, it has been rare to achieve simultaneous enhancement in strength and ductility, i.e., to disrupt the trade-off relationship. Here via rotary swaging and subsequent annealing, we prepared a macro dual-cable structured Cu–Al alloy rod with an inner micro-grain (MG) core (2.2 mm in diameter, 54% volume fraction) wrapped in an outer ultrafine-grain (UFG) shell (a thickness of 0.4 mm). Tensile tests revealed that the inner core has a yield strength of 472 MPa and a ductility of 29.1%, while the wrapping of the outer shell simultaneously enhances the yield strength to 552 MPa and ductility to 31.9%, respectively. The analysis of strain during the stretching process shows that the shell has a strong restraining effect on the core. Microstructure characterization indicates that the core blocks the propagation of the shear bands of shell and maximizes its density. At the same time, the restriction of the shell increases the lattice defect accumulation and work hardening ability as well as ductility of the core. Our research not only provides a method for preparing macro dual-cable structured materials with industrial scale and clean interface, but also explores a new strategy for simultaneously enhancing strength and ductility of metals, which designs macro millimeter-scale structures instead of adjusting microstructure from the micrometer scale.
金属强度和延展性的权衡关系导致强度增加的同时延展性降低。在过去的二十年中,尽管人们做出了巨大努力,通过定制微结构来提高强度,同时尽量减少延展性的损失,但同时提高强度和延展性,即打破这种权衡关系的情况却很少见。在此,我们通过旋转锻造和随后的退火,制备了一种宏观双缆结构铜铝合金棒材,其内部为微细晶粒(MG)内核(直径 2.2 毫米,体积分数 54%),外部包裹着超细晶粒(UFG)外壳(厚度 0.4 毫米)。拉伸试验显示,内芯的屈服强度为 472 兆帕,延展性为 29.1%,而包裹外壳的内芯屈服强度和延展性分别提高到 552 兆帕和 31.9%。拉伸过程中的应变分析表明,外壳对内核具有很强的约束作用。显微结构表征表明,芯材阻止了壳的剪切带的扩展,并使其密度最大化。同时,壳的限制增加了晶格缺陷的积累和加工硬化能力,并提高了芯的延展性。我们的研究不仅为制备具有工业规模和洁净界面的宏观双缆结构材料提供了方法,而且探索了同时提高金属强度和延展性的新策略,即设计宏观毫米尺度结构,而不是从微米尺度调整微观结构。
Insight into faceted-nonfaceted transition of directionally solidified eutectic ceramic composites by laser floating zone melting and infrared imaging
Di Zhao, Haijun Su, Shuqi Hao, Zhonglin Shen, Yinuo Guo, Yuan Liu, Peixin Yang, Zhuo Zhang, Min Guo
doi:10.1016/j.compositesb.2024.111372
通过激光浮动区熔化和红外成像观察定向凝固共晶陶瓷复合材料的切面-非切面转变
Faceted-nonfaceted transition was found during directional solidification of an Al2O3/Y3Al5O12(YAG)/ZrO2 eutectic ceramic composite at the pulling rate over 260 μm/s by laser floating zone melting. This transition, for the first time, optimized the colony structure of faceted eutectic composite materials, resulting in a refined and homogeneous microstructure consisting of both rod and lamella. Infrared imaging was employed to uncover temperature field evolution of the melt during the transition relying on an interesting measurement calibration strategy. In addition to an in-depth discussion about this evolution, we revealed that the transition was triggered by a critical undercooling at the solid-liquid interface. A 3D model of this novel eutectic structure was established, by which the mechanism of structural optimization achieved by the transition was discussed. We supposed that the growth orientation with the smallest index could firstly occur faceted-nonfaceted transition under a certain undercooling degree, and subsequently predominated the growth of faceted eutectic composites, which contributed to the optimization of faceted eutectic colony structure.
通过激光浮区熔化法,在拉速超过 260 μm/s 的条件下定向凝固 Al2O3/Y3Al5O12(YAG)/ZrO2 共晶陶瓷复合材料时,发现了面状-非面状转变。这一转变首次优化了面状共晶复合材料的菌落结构,形成了由棒状和片状组成的精细均匀的微观结构。红外成像技术利用一种有趣的测量校准策略,揭示了转变过程中熔体温度场的演变。除了对这一演变过程进行深入探讨外,我们还揭示了这一转变是由固液界面的临界过冷引发的。我们建立了这种新型共晶结构的三维模型,并据此讨论了转变所实现的结构优化机制。我们认为,在一定的过冷度下,指数最小的生长取向会首先发生刻面-非刻面转变,随后刻面共晶复合材料的生长占主导地位,这有助于优化刻面共晶菌落结构。
Material representativeness of a polymer matrix doped with nanoparticles as the random speckle pattern for digital volume correlation of fibre-reinforced composites
Thanasis Chatziathanasiou, Okan Demir, Jeroen Soete, Christian Breite, Mahoor Mehdikhani, Martin Diehl, Yentl Swolfs
doi:10.1016/j.compositesb.2024.111381
掺杂纳米颗粒的聚合物基体的材料代表性,作为纤维增强复合材料数字体积相关性的随机斑点模式
Combining tomographic imaging with digital volume correlation allows in-situ 3D strain mapping, leading to a quantitative assessment of damage mechanisms and associated material properties in structural materials. Being based on pattern recognition, digital volume correlation is well-suited for materials with intrinsic and stable microstructural heterogeneity, such as certain biological tissues. Unfortunately, conventional polymers and fibre-reinforced polymer composites lack the required heterogeneity. Recently, solutions like doping the polymers with particles have been explored to overcome this limitation. The particles embedded in the polymer matrix provide a random, volumetric speckle pattern, acting as displacement trackers for the digital volume correlation algorithm. However, the particles might influence the mechanical and rheological behaviour of the polymer, which is detrimental in investigations of the composite material properties. This paper investigates the mechanical, mechanistic, and rheological representativeness of an epoxy doped with two types of sub-micrometre particles optimised for digital volume correlation. Since particle dispersion is considered a key driver for representativeness, we simultaneously quantitatively assess the dispersion by combining scanning electron microscopy and X-ray computed tomography.
将断层成像与数字体积相关技术相结合,可进行原位三维应变绘图,从而对结构材料的损伤机制和相关材料特性进行定量评估。数字体积相关技术以模式识别为基础,非常适合具有内在和稳定的微观结构异质性的材料,如某些生物组织。遗憾的是,传统聚合物和纤维增强聚合物复合材料缺乏所需的异质性。最近,人们探索了在聚合物中掺入微粒等解决方案,以克服这一局限性。嵌入聚合物基体中的微粒提供了随机的体积斑点模式,可作为数字体积相关算法的位移跟踪 器。然而,颗粒可能会影响聚合物的机械和流变特性,这不利于对复合材料特性的研究。本文研究了掺杂了两种亚微米颗粒的环氧树脂在机械、力学和流变学方面的代表性,并对数字体积相关性进行了优化。由于颗粒的分散性被认为是影响代表性的关键因素,我们同时结合扫描电子显微镜和 X 射线计算机断层扫描对分散性进行了定量评估。