今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Science and Technology 3 篇
Broadband and robust vibration reduction in lattice-core sandwich beam with 3D-printed QZS resonators
Lei Xiao, Xiang Sun, Li Cheng, Xiang Yu
doi:10.1016/j.compstruct.2024.118626
3d打印QZS谐振器在格芯夹层梁中的宽带和鲁棒减振
The demand for lightweight lattice-core sandwich structures that exhibit superior mechanical and dynamic properties is widespread in many devices. This paper presents a lattice-core sandwich beam (LSB) with an embedded array of quasi-zero-stiffness (QZS) resonators, referred to as Q-LSB. This research distinguishes itself from existing studies on metamaterial structures with QZS resonators by investigating the nonlinear stiffness of QZS resonators and the damping of a soft three-dimensional (3D) printing material. The objective is to achieve efficient and robust vibration reduction beyond the band gap of its linear counterpart. We investigate the beam vibration using both experimental and numerical methods. The experimental results demonstrate that the resonators can entail significant vibration reduction in a wide frequency range, covering the first three eigenmodes of the host LSB. Furthermore, the reduction effect improves as the excitation level increases within the tested excitation range, highlighting the structure’s robustness against the excitation amplitude. A numerical model based on a dynamically equivalent homogenization method and the finite element method is established and experimentally validated. Subsequently, the numerical parametric results reveal that the broadband vibration reduction is due to the damping effect, while the robust vibration reduction effect is attributed to the nonlinear stiffness of the resonators.
在许多器件中,对具有优异力学和动态性能的轻质格芯夹层结构的需求是广泛存在的。本文提出了一种嵌入准零刚度(QZS)谐振器阵列的格芯夹层梁(LSB),简称Q-LSB。本研究通过研究QZS谐振器的非线性刚度和软三维(3D)打印材料的阻尼,与现有的QZS谐振器超材料结构研究不同。目标是实现有效和稳健的减振超出其线性对应的带隙。我们用实验和数值方法研究了梁的振动。实验结果表明,谐振器可以在较宽的频率范围内显著降低振动,覆盖宿主LSB的前三个特征模态。此外,在测试的激励范围内,随着激励水平的增加,减少效果也会改善,这突出了结构对激励幅度的鲁棒性。建立了基于动态等效均匀化法和有限元法的数值模型,并进行了实验验证。随后,数值参数分析结果表明,宽带减振是由于阻尼效应,而鲁棒减振是由于谐振器的非线性刚度。
Fracture simulation of fiber reinforced composite panels with holes
Yang Zhang, Jialu Guo, Zhan Shu, Yaojing Guan, A.S. Ademiloye
doi:10.1016/j.compstruct.2024.118627
带孔纤维增强复合材料板断裂模拟
Fiber reinforced composite (FRC) with holes have broad applications in various fields. In this study, the influence of fiber orientation and hole distribution on the fracture behavior of FRC was investigated. A phase-field modeling was established to simulate the fracture process of the composite, and the mechanical performance of unidirectional fiber reinforced composite and woven fiber reinforced composite were analyzed, respectively. Our numerical results showed that fiber orientation and hole distribution have a significant impact on the fracture behavior of FRC. We observed that aligning the fibers parallel to the loading direction led to an increase in the maximum load bearing capacity of the composite. A more uniform hole distribution can enhance the overall mechanical performance of FRC. Furthermore, in the presence of thermal shock, crack propagation tends to grow towards the hole. These findings are of great significance for understanding the fracture behavior of FRC, and for optimizing material design and fabrication processes.
带孔纤维增强复合材料在各个领域有着广泛的应用。本文研究了纤维取向和孔分布对FRC断裂行为的影响。建立相场模型,模拟复合材料的断裂过程,分别对单向纤维增强复合材料和编织纤维增强复合材料的力学性能进行了分析。数值结果表明,纤维取向和孔洞分布对纤维纤维的断裂行为有显著影响。我们观察到,平行于加载方向的纤维排列导致复合材料的最大承载能力增加。孔分布越均匀,FRC的整体力学性能越好。此外,在热冲击存在时,裂纹扩展倾向于向孔方向扩展。这些发现对于理解FRC的断裂行为,优化材料设计和制造工艺具有重要意义。
Structural response of glass fiber-polymer composite bending-active elastica beam under long-term loading conditions
Tara Habibi, Landolf Rhode-Barbarigos, Thomas Keller
doi:10.1016/j.compstruct.2024.118628
长期荷载作用下玻璃纤维-聚合物复合材料主动弯曲弹性梁的结构响应
Bending-active elastica beams represent structural members which are initially installed as straight beams and then bent into arched shapes by applying horizontal displacements to one support. Designing such members for permanent structures made of fiber-polymer composites involves complex viscoelastic responses, which have not yet been thoroughly investigated. An experimental investigation of medium-scale bending-active elastica beams, consisting of pultruded glass fiber-polymer composite profiles, was thus conducted to investigate the long-term structural behavior of such members under imposed sustained bending and axial compression. The results revealed that viscoelastic responses are based on an interaction of stress relaxation and creep with their effects increased with increasing bending degree and time of exposure to sustained strains and stresses. The imposed horizontal displacement to one of the supports to maintain the bent beam shape induced sustained bending stresses in the beam. Beneficial relaxation of these stresses occurred with relaxation predicted to reach 12 % during a targeted 50-year design service life. Furthermore, the likelihood of the curved beam exhibiting in-plane deformations under sustained stresses enabled creep to occur simultaneously, with associated in-plane creep deformations and strength reduction. While creep deformations remained insignificant, progressive creep rupture occurred at highest bending degrees, exhibiting sequential creep rupture in the outer combined mat layers, delamination, crack opening and final fiber failure. Creep rupture can be prevented by postponing crack initiation in the combined mat layer beyond the targeted design service life. This can be achieved by limiting the bending degree to 50 % of the bending degree at which short-term crack initiation occurs.
主动弯曲弹性梁是指最初作为直梁安装的结构构件,然后通过对一个支撑施加水平位移而弯曲成拱形。为由纤维-聚合物复合材料制成的永久性结构设计此类构件涉及复杂的粘弹性响应,这方面的研究尚未深入。因此,对由拉挤玻璃纤维-聚合物复合材料型材组成的中尺度弯曲主动弹性梁进行了实验研究,以研究此类构件在施加持续弯曲和轴向压缩下的长期结构行为。结果表明,粘弹性响应是基于应力松弛和蠕变的相互作用,其影响随着弯曲程度和持续应变和应力暴露时间的增加而增加。施加在其中一个支座上的水平位移以保持弯曲梁的形状,从而在梁中产生持续的弯曲应力。这些应力发生了有益的松弛,在目标50年的设计使用寿命期间,松弛率预计达到12% %。此外,弯曲梁在持续应力下表现出面内变形的可能性使蠕变同时发生,并伴有面内蠕变变形和强度降低。当蠕变不明显时,在最高弯曲度处发生渐进性蠕变断裂,表现为外层复合层的顺序蠕变断裂、分层、开裂和最终纤维破坏。通过将组合垫层中的裂纹起始推迟到目标设计使用寿命之后,可以防止蠕变破裂。这可以通过将弯曲度限制在产生短期裂纹的弯曲度的50% %来实现。
Characterization and property prediction of fibre structures within discontinuous-fibre reinforced polymer matrix composites using 3D fibre cells assisted by contrastive learning
Yuheng Zhou, Pascal Hubert
doi:10.1016/j.compositesa.2024.108506
利用对比学习辅助的三维纤维细胞对非连续纤维增强聚合物基复合材料中的纤维结构进行表征和性能预测
Fibre-cell-based fibre structure characterization approach was proposed recently to characterize the fibre distribution within discontinuous-fibre reinforced polymer matrix composites (DFR PMCs) over a 2D domain. This approach determines the distribution state of each fibre based on the relative size and topological features of its fibre cell. In this study, the fibre-cell-based approach is extended for 3D fibre domains. A convolutional neural network (CNN) encoder is trained through contrastive learning to quantitatively represent topological features of 3D fibre cells. Subsequently, the feature-property correlations are established using an artificial neural network (ANN). For practical application, the ANN is integrated with an image analysis software to provide in situ predictions of local elastic modulus of a DFR PMC based on its fibre structures observed from micro-CT images. The predictions are also compared with the experimental measurements acquired through microindentation testing, and it shows a good agreement.
最近提出了一种基于纤维细胞的纤维结构表征方法,用于表征非连续纤维增强聚合物基复合材料(DFR PMCs)内的二维纤维分布。这种方法根据纤维细胞的相对大小和拓扑特征来确定每根纤维的分布状态。在本研究中,基于纤维细胞的方法扩展到三维纤维域。通过对比学习训练卷积神经网络(CNN)编码器,定量表征三维纤维细胞的拓扑特征。随后,使用人工神经网络(ANN)建立特征-属性相关性。在实际应用中,人工神经网络与图像分析软件相结合,根据微ct图像观察到的纤维结构,提供DFR PMC局部弹性模量的原位预测。并将预测结果与微压痕试验结果进行了比较,结果表明预测结果吻合较好。
Design of experiments investigation into the production of all cellulose composites using regenerated cellulosic textiles
Ashley Victoria, Peter John Hine, Keeran Ward, Michael Edward Ries
doi:10.1016/j.compositesa.2024.108510
利用再生纤维纺织品生产全纤维素复合材料的实验设计研究
All cellulose composites (ACCs) can be produced from native and man-made cellulosic fibres; use of the latter provides an additional application for waste-derived regenerated fibers. ACCs were prepared using an ionic liquid dissolution method, utilizing a regenerated cellulose (Tencel) textile, with and without an interleaf cellulosic film. A design of experiments methodology was applied to explore process-property relationships; concentration of the ionic liquid and the processing time and temperature were investigated. It was found that the film remained in-between the textile layers, rather than penetrating the fiber assembly, in contrast to our previous work on cotton-based ACCs. This is due to the structural differences between Tencel and cotton fabric. A multi-response optimization was conducted through a central composite face centered strategy, which captured the film system more strongly. Optimized processing conditions were identified, yielding a Young’s modulus and strain-to-failure of 5.3 GPa and 3.5% respectively,;alidated through in-lab samples.
所有纤维素复合材料(ACCs)都可以由天然和人造纤维素纤维生产;后者的使用为废物衍生的再生纤维提供了额外的应用。采用离子液体溶解法,利用再生纤维素(天丝)织物,有或没有交错的纤维素膜制备acc。采用实验设计方法探索工艺-性能关系;考察了离子液体的浓度、处理时间和温度。我们发现,薄膜仍然在纺织层之间,而不是穿透纤维组件,这与我们之前对棉基ACCs的研究相反。这是由于天丝和棉织物的结构差异。采用中心复合面为中心策略进行多响应优化,更强地捕获了薄膜系统。确定了优化的加工条件,杨氏模量和应变破坏比分别为5.3 GPa和3.5%,并通过实验室样品进行了验证。
Experimental and numerical validation of high strain rate impact response and progressive damage of 3D orthogonal woven composites
Xue Yang, Dian-sen Li, Xiao-long Jia, Hong-mei Zuo, Lei Jiang, Stepan V. Lomov, Frederik Desplentere
doi:10.1016/j.compscitech.2024.110896
三维正交编织复合材料高应变率冲击响应及渐进损伤的实验与数值验证
Advanced three-dimensional (3D) woven composites for aerospace and automotive applications are commonly subjected to complex dynamic environments involving vibrations and impacts, resulting in examining their impact properties is extremely important. This paper first experimentally discussed the influences of strain rates, weft yarn densities and loading directions on the impact performances and failure mechanisms of 3D orthogonal woven composites (3DOWCs). Secondly, full-scale finite element models were developed to predict the stress distribution and interfacial damage evolution process. The predictions were well in agreement with the experimental results. This research revealed that the impact characteristics exhibited strain rate sensitivity. With increasing weft yarn densities, the high strain rate impact behaviors also improved. Particularly, the warp impact strength of 3DOWCs with a weft yarn density of 2 yarn/cm (W5-2) at 812 s-1 was 17.4% and 24.0% higher than that of 3DOWCs with a weft yarn density of 1.5 yarn/cm (W5-1) at 822 s-1. Meanwhile, warp impact strength consistently exceeded to that of the weft impact strength. Additionally, strain rates, weft yarn densities, and loading directions dramatically affected the stress distribution and interfacial damage evolution process of 3DOWCs. Significant warp yarns fracture and matrix cracking were the principal failure patterns in the warp impact, whereas the damage in the weft impact was dominated by localized fracture of weft yarns and interfacial debonding.
用于航空航天和汽车应用的先进三维(3D)编织复合材料通常会受到涉及振动和冲击的复杂动态环境的影响,因此检查其冲击性能非常重要。本文首先通过实验研究了应变率、纬纱密度和加载方向对三维正交编织复合材料(3DOWCs)冲击性能和破坏机理的影响。其次,建立全尺寸有限元模型,预测应力分布和界面损伤演化过程;预测结果与实验结果非常吻合。研究表明,冲击特性具有应变率敏感性。随着纬纱密度的增加,高应变率冲击性能也得到改善。纬纱密度为2支/cm (W5-2)的3DOWCs在812 s-1下的经纱冲击强度比纬纱密度为1.5支/cm (W5-1)的3DOWCs在822 s-1下的经纱冲击强度分别提高了17.4%和24.0%。同时,经纱冲击强度不断超过纬纱冲击强度。应变速率、纬纱密度和加载方向对三维dowcs的应力分布和界面损伤演化过程有显著影响。经纱断裂和基体开裂是经纱冲击的主要破坏形式,纬纱局部断裂和界面脱粘是纬纱冲击的主要破坏形式。
Post Impact Flexural Behavior Investigation of Hybrid Foam-Core Sandwich Composites at Extreme Arctic Temperature
Faizan Mirza, Jason P. Mack, Arnob Banik, M.H. Khan, K.T. Tan
doi:10.1016/j.compscitech.2024.110897
极端北极温度下混杂泡沫芯夹层复合材料冲击后弯曲行为研究
This study explores the post-impact bending behavior and failure mechanisms in hybrid sandwich composites made of Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP). Flexural tests conducted at both ambient room temperature and low temperature Arctic conditions reveal a significant enhancement in flexural performance when GFRP layer is incorporated on the outer side of the hybrid composite. The investigation utilizes images from testing to elucidate damage modes, including fiber and matrix cracking in the composite facesheet, as well as core shearing and debonding in the Polyvinyl Chloride (PVC) foam core. Residual flexural properties are notably influenced by stacking sequence, facesheet compressive properties, pre-existing impact damage and temperature conditions. Analytical predictions, validated experimentally, highlight the effect of stacking sequence, low temperature, and impact energy on flexural collapse modes, with competing failure modes such as indentation and core shear. Collapse maps indicate that room temperature specimens predominantly collapse through indentation, while diverse collapse mechanisms emerge due to facesheet thickness, rigidity, and degraded tensile strength. The study aims to provide fundamental insights for future composite designs tailored for Arctic applications.
本研究探讨了碳纤维增强聚合物(CFRP)和玻璃纤维增强聚合物(GFRP)混合夹层复合材料的冲击后弯曲行为和破坏机制。在室温和北极低温条件下进行的弯曲试验表明,在混合复合材料的外侧加入玻璃钢层后,弯曲性能显著增强。该研究利用测试图像来阐明损伤模式,包括复合材料表面的纤维和基体开裂,以及聚氯乙烯(PVC)泡沫芯的剪切和脱粘。残余弯曲性能受堆积顺序、表面压缩性能、预先存在的冲击损伤和温度条件的显著影响。经过实验验证的分析预测强调了堆积顺序、低温和冲击能量对弯曲破坏模式的影响,以及压痕和核心剪切等竞争破坏模式。坍塌图表明,室温试样主要通过压痕坍塌,而由于面板厚度、刚度和抗拉强度下降,出现了多种坍塌机制。该研究旨在为未来针对北极应用量身定制的复合材料设计提供基本见解。
Synergistic enhancement of magic triangle properties of PC tread stocks modified by amine-capped trans-1,4-poly (butadiene-co-isoprene)
Shufang Luo, Kaixuan Dong, Shuo Wang, Aihua He
doi:10.1016/j.compscitech.2024.110899
胺包覆反式-1,4-聚丁二烯-co-异戊二烯改性PC胎面胶的魔三角性能协同增强
The development of high-performance “green tires” with synergistically improved “magic triangle” properties like lower rolling resistance, higher wet-skid resistance and higher abrasion resistance has always been a hot issue. In this work, an effective strategy for developing high-performance “green tires” with simultaneously improved “magic triangle” properties of solution-polymerized styrene-butadiene rubber (SSBR)/cis-1,4-polybutadiene rubber (BR) nanocomposites modified by amine-capped trans-1,4-poly(butadiene-co-isoprene) copolymers (F-TBIR) was proposed. A series of F-TBIR with 10-60 mol% amine-capped efficiency (CE) and 30-90×104 weight-average molecular weight (Mw) were synthesized by using heterogeneous TiCl4/MgCl2-Al(i-Bu)3 Ziegler-Natta catalyst with dicyclohexylamine (DCHA) as chain transfer agent (CTA). With the increase in CE of F-TBIR, the silica-filled SSBR/BR/F-TBIR compounds exhibited improved green strength, modulus at 100% elongation and bound rubber, and their vulcanizates showed synergistically improved “magic triangle” properties like obviously reduced rolling resistance and abrasion loss, and increased wet-skid resistance. It was found that the incorporation of 10 phr F-TBIR3 with CE of 60% and Mw of 32×104 resulted in highly expected properties of the SSBR/BR/F-TBIR3 nanocomposite. The contribution mechanism of F-TBIR3 was discussed based on the improvements of polymer network structures and filler network structures. This work is expected to provide an effective strategy to construct the desired network structures for high-performance rubber composites.
高性能“绿色轮胎”在降低滚动阻力、提高湿滑阻力和耐磨性等“魔术三角”性能的协同提升方面,一直是研究的热点问题。本研究提出了一种有效策略,通过使用胺封端的顺式-1,4-聚(丁二烯-共-异戊二烯)共聚物(F-TBIR)改性的溶液聚合苯乙烯-丁二烯橡胶(SSBR)/顺式-1,4-聚丁二烯橡胶(BR)纳米复合材料,来开发高性能的“绿色轮胎”,并实现“魔术三角”性能的同步改善。采用TiCl4/MgCl2-Al(i-Bu)3 Ziegler-Natta催化剂体系,以二环己胺(DCHA)为链转移剂,合成了胺封端效率(CE)为10%-60%、重均分子量(Mw)为30-90×10⁴的系列F-TBIR。随着F-TBIR CE的增加,填充了硅石的SSBR/BR/F-TBIR化合物表现出提高的绿色强度、100%伸长率下的模量和结合橡胶含量,其硫化物表现出协同改善的“魔术三角”性能,包括明显降低的滚动阻力和磨损损失,以及提高的湿滑阻力。研究发现,当引入10份质量比的F-TBIR3(CE为60%,Mw为32×10⁴)时,SSBR/BR/F-TBIR3纳米复合材料表现出理想的性能。基于聚合物网络结构和填料网络结构的改善,讨论了F-TBIR3的贡献机制。本研究有望为构建高性能橡胶复合材料的理想网络结构提供一种有效策略。