今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 4 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 4 篇
A novel cellular structure with center-symmetric cell walls for morphing applications
Dezhi Wu, Guang Yang, Jianguo Tao, Yue Wang, Hong Xiao, Hongwei Guo
doi:10.1016/j.compstruct.2024.118644
具有中心对称细胞壁的新型细胞结构用于变形应用
Cellular structures are potential candidates for the supporting framework of flexible morphing skins. Unlike traditional zero Poisson’s ratio (ZPR) cellular structures with axisymmetric cell walls, this paper proposes a novel cellular structure with center-symmetric cell walls. The in-plane mechanical properties of this novel structure are explored through theoretical analysis and substantiated by both finite element simulations and experimental tests. Compared to the classic accordion honeycomb structure, the elastic modulus in the x-direction of the novel structure is reduced by an average of 58%, the strain amplification rate is increased by 122%, and the in-plane stiffness anisotropy is improved by 200%. These findings suggest that the proposed structure offers far superior stiffness anisotropy and large deformation potential, making it more suitable for morphing applications than the traditional ZPR cellular structures.
细胞结构是柔性变形皮肤支持框架的潜在候选者。与传统的轴对称细胞壁零泊松比(ZPR)细胞结构不同,本文提出了一种中心对称细胞壁的新型细胞结构。通过理论分析探索了这种新型结构的面内力学性能,并进行了有限元模拟和实验验证。与经典手风琴蜂窝结构相比,该结构x方向弹性模量平均降低58%,应变放大率提高122%,面内刚度各向异性提高200%。这些发现表明,所提出的结构具有优越的刚度各向异性和大的变形潜力,使其比传统的ZPR细胞结构更适合变形应用。
In-plane properties of an in-situ consolidated automated fiber placement thermoplastic composite
Timothy Yap, Nathaniel Heathman, Behrooz Shirani Bidabari, Emile Motta de Castro, Ali Tamijani, Amir Asadi, Mehran Tehrani
doi:10.1016/j.compositesa.2024.108525
原位固结自动铺放纤维热塑性复合材料的面内性能
Automated fiber placement (AFP) has been employed to manufacture aerospace structures for decades, recently focusing on thermoplastic composites (TPC). The in-situ consolidation AFP of TPCs is pursued as an energy-efficient additive manufacturing (AM) approach for fabricating composite structures. This work compares the in-plane mechanical properties of in-situ consolidated coupons with those of compression molded counterparts to provide new insights into their failure mechanics and processing-structure relationships. Tensile and compressive properties along the fiber and transverse directions, in-plane shear properties, and short beam strength were measured for all samples. Failure modes and mechanics in tested coupons were related to AFP defects and processing, i.e., resultant crystallinities, fiber misalignment, matrix mechanical properties, porosity, and fiber–matrix interfacial strength. The findings of this study can be used to guide the manufacturing of future TPC structures and potentially open new avenues for applications where post-processing is not feasible or reduced mechanical performance is acceptable.
自动纤维铺放技术(AFP)已经应用于航空航天结构制造几十年了,最近的重点是热塑性复合材料(TPC)。原位固结复合材料是一种高效节能的增材制造(AM)方法。这项工作比较了原位固结板与压缩成型板的平面内力学性能,为其破坏机制和加工-结构关系提供了新的见解。测试了所有样品沿纤维方向和横向的拉伸和压缩性能、面内剪切性能和短梁强度。试样中的失效模式和力学与AFP缺陷和加工有关,即结晶度、纤维错位、基体力学性能、孔隙率和纤维-基体界面强度。这项研究的结果可用于指导未来TPC结构的制造,并可能为后处理不可行的应用或降低机械性能可接受的应用开辟新的途径。
Bearing performance and progressive failure analysis of bolted joint in 3D printed pseudo-woven CFRP composite with fibre steering
Aonan Li, Haoqi Zhang, Dongmin Yang
doi:10.1016/j.compositesa.2024.108526
3D打印纤维转向伪编织CFRP复合材料螺栓连接承载性能及渐进失效分析
This study investigates the bearing failure process of 3D printed pseudo-woven carbon fibre reinforced polymer (CFRP) composite joints, with a particular focus on the damage mechanisms influenced by steered fibres. A multiscale finite element model employing LaRC05 failure criteria is developed and validated against the experimental load–displacement curves and micro-computed microtomography (CT) images of four distinct cases. The model clearly demonstrates the critical importance of maintaining fibre continuity around the bolt hole, as this significantly influences the ability to reduce stress concentrations caused by the direct bearing loads from the bolt. Moreover, the model reveals that fibre steering can substantially improve the composite joint’s performance. This enhancement is achieved by adjusting the level of shear-induced damage propagation in individual filaments. The results demonstrate the potential and capability of the model to capture individual filament behaviour for the failure analysis of 3D printed composites, achieving good correlations with experimental measurements and observations, in terms of failure modes and load-bearing capacities.
本文研究了3D打印伪编织碳纤维增强聚合物(CFRP)复合材料接头的承载破坏过程,重点研究了定向纤维对其损伤机制的影响。采用LaRC05失效准则建立了一个多尺度有限元模型,并根据实验载荷-位移曲线和四种不同情况的微计算机微断层扫描(CT)图像进行了验证。该模型清楚地表明,保持螺栓孔周围纤维的连续性至关重要,因为这极大地影响了降低由螺栓直接承载载荷引起的应力集中的能力。此外,该模型还表明,纤维转向可以显著提高复合材料接头的性能。这种增强是通过调整单个细丝中剪切引起的损伤传播水平来实现的。结果表明,该模型具有捕获单个细丝行为的潜力和能力,可用于3D打印复合材料的失效分析,在失效模式和承载能力方面,与实验测量和观察结果具有良好的相关性。
The moisture absorption of additively manufactured short carbon fibre reinforced polyamide
Yingwei Hou, Ajit Panesar
doi:10.1016/j.compositesa.2024.108528
增材制造短碳纤维增强聚酰胺的吸湿性能
Polymer composites are commonly exposed to moisture and undergo reductions in mechanical properties. It is challenging to describe the moisture absorption dynamics of 3D printed parts due to manufacture-induced microstructures. This work investigates the moisture absorption of printed short carbon fibre reinforced polyamide (SFRP) with varied microstructures and its impact on mechanical properties. The printed SFRP have inferior microstructures and diffusivity increases with the number of interlayer interfaces by up to 119%, which is 258% higher than that of compression moulded composite. The yield stress and tensile modulus of SFRP decrease by up to 59% and 79%, respectively. This deterioration is irreversible and more significant than injection moulded samples as the microstructure is permanently degraded by moisture. Additionally, the shear moduli of printed polyamide and SFRP decrease by up to 63% and 74%, respectively. The results are crucial for prediction, evaluation, and maintenance of 3D printed applications in humid conditions.
聚合物复合材料通常暴露在潮湿中,机械性能会降低。由于制造诱导的微结构,描述3D打印部件的吸湿动力学具有挑战性。本文研究了不同微观结构的印刷短碳纤维增强聚酰胺(SFRP)的吸湿性能及其对力学性能的影响。打印后的SFRP具有较差的微观结构,其扩散系数随着层间界面数量的增加而提高了119%,比压缩成型复合材料提高了258%。SFRP的屈服应力和拉伸模量分别降低了59%和79%。这种劣化是不可逆的,并且比注射成型样品更重要,因为微观结构被水分永久劣化。此外,打印聚酰胺和SFRP的剪切模量分别下降了63%和74%。研究结果对于潮湿条件下3D打印应用的预测、评估和维护至关重要。
Translaminar fracture in (non–)hybrid thin-ply fibre-reinforced composites: An in-depth examination through a novel mini-compact tension specimen compatible with microscale 4D computed tomography
Sina AhmadvashAghbash, Guillaume Broggi, Abdullah Aydemir, Alexios Argyropoulos, Joël Cugnoni, Véronique Michaud, Mahoor Mehdikhani, Yentl Swolfs
doi:10.1016/j.compositesa.2024.108529
(非)混杂薄层纤维增强复合材料的跨层断裂:通过与微尺度4D计算机断层扫描兼容的新型微型紧凑型拉伸试样进行深入检查
Translaminar fracture toughness is pivotal for notch sensitivity and damage tolerance of fibre-reinforced composites. Hybridisation offers a promising pathway for enhancing this parameter in thin-ply composites. Three novel mini-compact tension specimen geometries were investigated for their competence in microscale characterisation of translaminar fracture using in-situ synchrotron radiation computed tomography (SRCT). Only “mini-protruded” design resulted in stable crack propagation with adequate crack increments. Based on this design, five baseline and hybrid cross-ply configurations incorporating low- and high-strain carbon fibres were studied. Crack propagation in low- and high-strain baseline configurations was stable. For interlayer and intrayarn fibre-hybrid configurations, a correlation between load–displacement curves and delamination is observed. The SRCT data confirmed that 90° ply-blocks cushion the interaction between 0° plies, enabling independent fracture. Additionally, crack fronts in 90° plies advance further than those in 0° plies. Moreover, mechanical interlocking and bundle bending within 0° plies serve as supplementary mechanisms for energy dissipation.
跨层断裂韧性是影响纤维增强复合材料缺口敏感性和损伤容限的关键因素。杂化为提高薄层复合材料的这一参数提供了一条很有前途的途径。利用原位同步辐射计算机断层扫描(SRCT)技术,研究了三种新型的微型紧致拉伸试样几何形状在跨椎板断裂微尺度表征中的能力。只有“微突出”设计导致裂纹扩展稳定且有足够的裂纹增量。基于这种设计,研究了包含低应变和高应变碳纤维的五种基线和混合交叉层配置。在低应变和高应变基线配置下,裂纹扩展是稳定的。对于层间和层内纤维混杂结构,观察到载荷-位移曲线与分层之间的相关性。SRCT数据证实,90°层段缓冲了0°层段之间的相互作用,实现了独立压裂。此外,90°层的裂缝前缘比0°层的裂缝前缘超前得多。此外,机械联锁和0°层内的束弯曲是能量耗散的补充机制。
A New Path Planning Strategy Driven by Geometric Features and Tensile Properties for 3D Printing of Continuous Fiber Reinforced Thermoplastic Composites
Wang Gongshuo, Wang Fuji, Guan Shouyan, Rao Fu, Wang Hongquan, Lei Yajing
doi:10.1016/j.compositesb.2024.111885
基于几何特征和拉伸性能的连续纤维增强热塑性复合材料3D打印路径规划策略
Three-dimensional (3D) printing technology for continuous fiber reinforced thermoplastic composites (C-FRTP), capable of rapid manufacturing of lightweight components with intricate geometric features, has emerged as one of the most promising technologies in the field of advanced composite manufacturing. Path planning is a crucial step for determining the fabrication quality of C-FRTP components. In this study, we proposed a new 3D printing path planning strategy driven by the geometric features and tensile properties of C-FRTP components. This strategy employed the properties of the Euler graph to generate the continuous full-field filling paths, ensuring the geometric features of the target components. The intersections were scattered along the printing path to enhance the tensile strength. The feasibility and advantages of the new path planning strategy were validated by comparative experiments with different printing paths. The results indicated that the new strategy not only achieved the geometric features of the target components but significantly enhanced their tensile strength. Using the printing path generated by the new path planning strategy, the tensile strength of specimens featuring mounting holes reached 349.4 MPa, which was only about 4.1% lower than the tensile strength of continuous fibers at straight paths. Compared to the existing contour-parallel path, the new strategy in this work improved the tensile properties by about 40.9%. The new path planning strategy proposed in this study shows great potential to design and fabricate C-FRTP components with enhanced mechanical properties for practical applications.
连续纤维增强热塑性复合材料(C-FRTP)的三维(3D)打印技术能够快速制造具有复杂几何特征的轻质部件,已成为先进复合材料制造领域最有前途的技术之一。路径规划是决定C-FRTP构件制造质量的关键步骤。在这项研究中,我们提出了一种新的3D打印路径规划策略,该策略由C-FRTP部件的几何特征和拉伸性能驱动。该策略利用欧拉图的特性生成连续的全场填充路径,保证了目标部件的几何特征。在打印路径上分散交点以提高拉伸强度。通过不同打印路径的对比实验,验证了新路径规划策略的可行性和优越性。结果表明,新策略既能满足目标部件的几何特征,又能显著提高目标部件的抗拉强度。采用新路径规划策略生成的打印路径,安装孔试件的抗拉强度达到349.4 MPa,仅比连续纤维在直线路径下的抗拉强度低4.1%左右。与现有的轮廓平行路径相比,新策略的拉伸性能提高了约40.9%。本研究提出的新的路径规划策略在设计和制造具有增强机械性能的C-FRTP部件的实际应用中具有很大的潜力。
Multiscale study of interfacial properties of carbon fiber reinforced polyphthalazine ether sulfone ketone resin matrix composites
Zhenyu Qian, Tianqi Zhu, Xingyao Liu, Xinyu Fan, Zhongwei Yan, Xigao Jian, Jian Xu
doi:10.1016/j.compscitech.2024.110906
碳纤维增强聚酞醚砜酮树脂基复合材料界面性能的多尺度研究
In view of the limitations of traditional research tools on interfacial failure mechanisms in fiber/PPESK composites, this work proposes a multiscale research tool to carry out an in-depth study of the interfacial behavior between fibers and matrix. Based on microdroplet debonding tests, at the mesoscopic scale, the influence of residual thermal stress on the interface damage mode is explored through finite element (FEM) simulations. The evolution mechanism of composite material interfaces in spatial and temporal dimensions is examined based on changes in interfacial stress distribution, energy dissipation, and damage morphology during the debonding process, which can be summarized as follows: accompanied by elastic-plastic deformation and friction effects, the progressive process from localized to complete failure presents a dominant Type II damage mode at the interface. To further explore the interface failure mechanism at the molecular level, an interface model of CF/PPESK composite materials was established using molecular dynamics (MD) method. By monitoring the atom movement trend, the "fiber-matrix displacement synergistic effect" in the interfacial shear damage process was revealed, thereby establishing a multiscale mapping relationship of composite material interface. Based on this, the combination of FEM and MD was utilized to investigate the interface damage process of composite materials under different service conditions and to reasonably predict the initiation and expansion of microcracks. This study provides a pioneering perspective on interface damage research in composite materials with a "top-down" multiscale approach.
鉴于传统研究工具对纤维/PPESK复合材料界面破坏机制的局限性,本工作提出了一种多尺度研究工具,以深入研究纤维与基体之间的界面行为。基于微液滴脱粘试验,在细观尺度上,通过有限元模拟探讨了残余热应力对界面损伤模式的影响。基于剥离过程中界面应力分布、能量耗散和损伤形态的变化,考察复合材料界面在时空维度上的演化机制,可归纳为:伴随着弹塑性变形和摩擦作用,界面从局部破坏到完全破坏的渐进过程以II型损伤模式为主;为了在分子水平上进一步探讨界面破坏机理,采用分子动力学(MD)方法建立了CF/PPESK复合材料的界面模型。通过对原子运动趋势的监测,揭示了界面剪切损伤过程中的“纤维-基质位移协同效应”,从而建立了复合材料界面的多尺度映射关系。在此基础上,采用有限元法和模态分析相结合的方法,研究了复合材料在不同使用条件下的界面损伤过程,合理预测了微裂纹的萌生和扩展。本研究为复合材料界面损伤研究提供了一个“自上而下”的多尺度方法。
Composite Janus film based on the synergistic interactions of π-π stacking and dynamic covalent bond toward direction recognition sensing
Yang Bai, Guoliang Yang, Zhong Jing, Boyuan Zhang, Xinrui Li, Guiqiang Fei
doi:10.1016/j.compscitech.2024.110913
基于π-π堆叠和动态共价键协同作用的方向识别传感复合Janus膜
Although flexible strain sensors have made important advancements recently, most of them are unable to recognize the direction of motion, which greatly limits their application in fields such as human-machine interaction. This paper presents the fabrication of a bilayer asymmetric composite film that exhibits Janus dual-sided characteristics and interfacial properties. Specifically, the two sides possess different chemical compositions and surface features. The strong π-π stacking interaction between carbon nanotubes (CNTs) and pyrene enables a tight coating on the surface of poly(glycidyl propyl urethane) (PGPU), resulting in excellent sensing capabilities and electromagnetic shielding properties for the composite material. This composite film can effectively monitor the amplitude and direction of motion. Firstly, pyrene-grafted polyurethane (PGPU) was synthesized including on dynamic covalent bonds. The tensile strength of different samples can reach up to 19.69 MPa, and the strain at break is up to 501.95%. Furthermore, PGPU/CNTs conductive composite films were fabricated by spray-coating carbon nanotubes (CNTs) onto PGPU, and the pyrene units in PGPU can effectively interact with CNTs via π-π stacking, ensuring that stable adhesion of CNTs layer during long-term usage. Due to the dynamic covalent bonds and hydrogen bonds inside PGPU, PGPU and PGPU/CNTs both exhibit well-performed self-healing capability. Notably, the Janus structure of PGPU/CNTs can adjust the positive and negative values of relative resistance based on stretchable and compressive status of CNTs layer. Thus, PGPU/CNTs are directionally sensitive and self-healing flexible wearable sensor, which might apply in human-machine interaction field.
虽然柔性应变传感器近年来取得了重要的进展,但它们大多无法识别运动方向,这极大地限制了它们在人机交互等领域的应用。本文介绍了一种具有双面特性和界面特性的双层非对称复合膜的制备方法。具体来说,两面具有不同的化学成分和表面特征。碳纳米管(CNTs)和芘之间的强π-π堆叠相互作用使得聚甘油三酯(PGPU)表面具有紧密的涂层,从而使复合材料具有优异的传感能力和电磁屏蔽性能。这种复合薄膜可以有效地监测运动的幅度和方向。首先合成了含动态共价键的芘接枝聚氨酯(PGPU)。不同试样的抗拉强度可达19.69 MPa,断裂应变可达501.95%。此外,通过在PGPU上喷涂碳纳米管(carbon nanotubes, CNTs)制备了PGPU/CNTs导电复合膜,PGPU中的芘单元可以通过π-π堆叠与CNTs有效相互作用,保证了长期使用过程中CNTs层的稳定粘附。由于PGPU内部的动态共价键和氢键,PGPU和PGPU/CNTs都表现出良好的自愈能力。值得注意的是,PGPU/CNTs的Janus结构可以根据CNTs层的可拉伸和压缩状态调节相对阻力的正负值。因此,PGPU/CNTs是一种方向敏感、自修复的柔性可穿戴传感器,有望应用于人机交互领域。
Experimental and Numerical Investigations on the Tensile Response of Pin-Loaded Carbon Fibre Reinforced Polymer Straps
Danijela Stankovic, James R. Davidson, Valentin Ott, Luke A. Bisby, Giovanni P. Terrasi
doi:10.1016/j.compscitech.2024.110915
引脚加载碳纤维增强聚合物带拉伸响应的实验与数值研究
Carbon fibre reinforced polymer (CFRP) pin-loaded looped straps are increasingly being used in a range of structural load-bearing applications, notably for bridge hanger cables in network arch rail and highway bridges. The static performance of such CFRP straps is investigated through experimental and numerical analyses. Finite element (FE) models based on both one-eighth and half pin-strap assembly geometries were modelled. The resulting strains, stresses, and applied loads were compared against experimental data obtained using Digital Image Correlation, Distributed Fibre Optic Sensing (DFOS), and Fibre Bragg Grating (FBG) Sensing. The FE models effectively captured local strain distributions around the vertex area, close to the pin ends of the straps, as well as in the mid-shaft region, and aligned reasonably with experimental observations. The half FE model accurately predicted the overall strain distribution when compared to DFOS data; however, higher strain magnitudes (by 0.45-10.2%) and larger strain reductions were observed in some locations. Regarding failure loads, the FE models agreed well with Schürmann's analytical solution and the maximum stress criterion, exhibiting less than 2.5% deviations from the experimental data. Furthermore, the predicted onset of strap failure (by delamination) in the half model agreed with experimental values, with a maximum variance of 9.2%.
碳纤维增强聚合物(CFRP)销加载环带越来越多地应用于一系列结构承重应用,特别是在网络拱轨道和公路桥梁的桥吊索中。通过试验和数值分析研究了碳纤维布带的静力性能。基于八分之一和二分之一针带装配几何形状的有限元模型进行了建模。将得到的应变、应力和施加的载荷与使用数字图像相关、分布式光纤传感(DFOS)和光纤布拉格光栅(FBG)传感获得的实验数据进行比较。有限元模型有效地捕获了顶点区域周围、靠近吊带销端以及中轴区域的局部应变分布,与实验观测值吻合较好。与DFOS数据相比,半有限元模型更准确地预测了整体应变分布;然而,在某些位置观察到更高的应变大小(0.45-10.2%)和更大的应变减小。在破坏荷载方面,有限元模型与sch<s:1> rmann解析解和最大应力准则吻合较好,与试验数据偏差小于2.5%。此外,在半模型中,预测的皮带失效(由分层)开始与实验值一致,最大方差为9.2%。
Hollow core-shell structure Fe3O4@Polypyrrole composites for enhanced electromagnetic wave absorption
Jiang Guo, Yukun Sun, Xu Li, Shaohua Xi, Mohamed M. Ibrahim, Hua Qiu, Gaber A.M. Mersal, Zeinhom M. El-Bahy, Vignesh Murugadoss, Waras Abdul, Fujian Zhou, Juanna Ren, Zhanhu Guo, Jianfeng Zhu
doi:10.1016/j.compscitech.2024.110917
中空核壳结构Fe3O4@Polypyrrole增强电磁波吸收复合材料
Due to the rapid development of electronic devices, the electromagnetic pollution has become increasingly serious. Developing electromagnetic wave absorption (EWA) materials with lightweight, strong absorption capacity and wide effective absorption bandwidth (EAB) becomes a research hotspot. In this work, the hollow-Fe3O4@polypyrrole (HFO@PPy) composites with core-shell structure were successfully synthesized by in situ polymerization method. The electromagnetic parameters could be adjusted by controlling the content of HFO in HFO@PPy. In addition, HFO@PPy composites show both dielectric and magnetic losses. The synergistic effect of both two losses contributes to an enhanced electromagnetic attenuation. The enhanced impedance matching is achieved by the composition (HFO and PPy) and designed unique structure (core-shell and hollow structure). The maximum reflection loss (RL) and EAB are -52.01 dB and 2.72 GHz at 3.1 mm for 60.0 wt% HFO@PPy composites. Therefore, by reasonably regulating the component content and optimizing the structural design, the EWA performance of HFO@PPy composites could be effectively improved, providing a significant inspiration for fabrication of microwave absorbers.
由于电子设备的快速发展,电磁污染日益严重。开发重量轻、吸收能力强、有效吸收带宽宽的电磁波吸收材料成为研究热点。本文采用原位聚合法制备了具有核壳结构的hollow-Fe3O4@polypyrrole (HFO@PPy)复合材料。通过控制HFO@PPy中HFO的含量,可以调节电磁参数。此外,HFO@PPy复合材料同时显示介电和磁损耗。这两种损耗的协同效应有助于增强电磁衰减。通过HFO和PPy组成和独特的结构(核壳和空心结构)实现了增强的阻抗匹配。60.0 wt% HFO@PPy复合材料在3.1 mm处的最大反射损耗(RL)和EAB分别为-52.01 dB和2.72 GHz。因此,通过合理调节组分含量和优化结构设计,可有效提高HFO@PPy复合材料的EWA性能,为微波吸收材料的制造提供重要启示。