今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 4 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Pullout behavior of recycled macro fibers in the cementitious matrix: analytical model and experimental validation
YUAN Hong, FAN Y.C., YOU X.M., FU Bing, ZOU Q.Q.
doi:10.1016/j.compstruct.2023.117690
水泥基质中再生大纤维的拉拔行为:分析模型和实验验证
A novel mechanical recycling method has been recently developed in the authors’ group for processing waste glass fiber-reinforced polymer (GFRP) composites into macro fibers, which are then incorporated into concrete to produce green fiber-reinforced concrete (FRC). The present study has been conducted for facilitating the characterization of the tensile properties of macro fiber reinforced concrete (MFRC). A trilinear bond-slip model based on the shear-lag theory has first been refined by introducing a slip coefficient to consider different slip behaviors at the final pullout stages. Such a refined trilinear bond-slip model is suitable for describing the bond-slip behavior of the recycled macro fibers embedded in the cementitious matrix. The bond parameters are obtained through an inverse analysis, in which an improved particle swarm optimization algorithm (PSO) is used. The predicted force-end slip curves are compared with the pullout test results, and a good agreement is observed counterparts with the integral absolute error (IAE) ranging from 3.05%-5.52%, demonstrating the feasibility of the proposed analytical model. A parametric study is finally conducted to examine the sensitivity of different parameters including the fiber geometries and bond properties on the pullout behavior of the macro fibers.
作者的研究小组最近开发了一种新的机械回收方法,用于将废玻璃纤维增强聚合物(GFRP)复合材料加工成大纤维,然后将其融入混凝土中,生产出绿色纤维增强混凝土(FRC)。本研究的目的是分析大纤维增强混凝土(MFRC)的拉伸特性。基于剪切滞后理论的三线性粘结滑移模型首先通过引入滑移系数进行了改进,以考虑最后拉拔阶段的不同滑移行为。这种改进后的三线粘结滑移模型适用于描述嵌入水泥基质中的再生大纤维的粘结滑移行为。粘结参数是通过反分析获得的,其中使用了改进的粒子群优化算法(PSO)。将预测的力端滑移曲线与拉拔测试结果进行比较,发现两者之间存在很好的一致性,其积分绝对误差(IAE) 在 3.05%-5.52% 之间,证明了所提分析模型的可行性。最后还进行了参数研究,以检验不同参数(包括纤维几何形状和粘结性能)对宏纤维拉拔行为的敏感性。
Ti-PEEK interpenetrating phase composites with minimal surface for property enhancement of orthopedic implants
Xie Haiqiong, Chen Junjie, Liu Fei, Wang Rui, Tang Yichuan, Wang Yiru, Luo Tao, Zhang Kaifei, Cao Jian
doi:10.1016/j.compstruct.2023.117689
具有最小表面的 Ti-PEEK 互穿相复合材料,用于提高骨科植入物的性能
Bioinspired interpenetrating phase composites (IPCs) present a promising strategy for augmenting the mechanical properties of materials, thereby synergistically enhancing the strength and fracture toughness of orthopedic implants. In this study, Ti6Al4V-PEEK IPCs were fabricated by pressing molten PEEK into additively manufactured Ti6Al4V scaffolds designed using minimal surface structures. The mutual spatial interpenetration and strong binding between Ti and PEEK were confirmed through CT detection and SEM analyses, revealing the presence of continuous constituents within biomimetic architectures. Due to interpenetration promoting interaction and efficient stress transfer of the two phases, IPCs enhances toughness and energy absorption by over 291% and 309% respectively while maintaining bone-compatible elastic modulus and higher strength. The mechanisms underlying stress dispersion, crack propagation resistance, and prolonged stress plateau period of IPCs were investigated through the utilization of digital image correlation (DIC) and finite element simulation techniques. Among the various types of IPCs investigated, Gyroid IPCs exhibit superior comprehensive mechanical properties, thereby facilitating the development of customized IPCs aimed at ensuring long-term stability in orthopedic implantation scenarios.
受生物启发的互穿相复合材料(IPC)是增强材料力学性能的一种有前途的策略,可协同增强骨科植入物的强度和断裂韧性。在这项研究中,通过将熔融的 PEEK 压入采用最小表面结构设计的添加式制造的 Ti6Al4V 支架中,制造出了 Ti6Al4V-PEEK IPC。通过 CT 检测和 SEM 分析证实了 Ti 和 PEEK 之间的空间互穿和强结合,揭示了生物仿生结构中存在连续的成分。由于相互渗透促进了两相之间的相互作用和有效应力传递,IPCs 在保持骨兼容弹性模量和更高强度的同时,韧性和能量吸收分别提高了 291% 和 309%。通过利用数字图像相关(DIC)和有限元模拟技术,研究了 IPCs 的应力分散、抗裂纹扩展和应力高原期延长的机理。在所研究的各种类型的 IPC 中,Gyroid IPC 表现出更优越的综合机械性能,从而促进了定制 IPC 的开发,以确保骨科植入应用中的长期稳定性。
Nonlinear electromechanical bending of bi-modular piezoelectric laminated beams
Zeng Shan, Yu Zhiyong, Wang Fei, Wang Kaifa, Wang Baolin
doi:10.1016/j.compstruct.2023.117718
双模块压电叠层梁的非线性机电弯曲
In this paper, the nonlinear electromechanical bending of a bi-modular piezoelectric laminated beam is studied based on the principle of minimum potential energy and the Adomian decomposition method. The different tensile-compressive Young’s modulus of the core and piezoelectric layers, and the different tensile-compressive piezoelectric coefficients are considered. The electromechanical governing equations and related boundary conditions are obtained by using the principle of minimum potential energy. The deflection, neutral layer and interlaminar stresses of the beam are solved by the Adomian decomposition method and the iterative method, and verified by the finite element model and Galerkin's method. Results show that the applied voltage and the bi-modular characteristics affect the position of the neutral layer and the interlaminar stresses. Compared with the bi-modular properties of the core layer, the influences of the bi-modular properties of the piezoelectric layer on the neutral layer are relatively unobvious. In addition, the interlaminar stresses between the piezoelectric layer and core layer can be increased or decreased, depending on the relative magnitude of the applied voltage ratio and the bi-modular ratio. The results obtained are helpful for the analysis of the electromechanical coupling mechanism and design of piezoelectric composites and structures with bi-modular characteristics.
本文基于最小势能原理和 Adomian 分解法研究了双模块压电层叠梁的非线性机电弯曲。考虑了芯层和压电层不同的拉伸-压缩杨氏模量以及不同的拉伸-压缩压电系数。利用最小势能原理得到了机电控制方程和相关边界条件。采用 Adomian 分解法和迭代法求解了梁的挠度、中性层和层间应力,并通过有限元模型和 Galerkin 方法进行了验证。结果表明,外加电压和双模块特性会影响中性层的位置和层间应力。与芯层的双模块特性相比,压电层的双模块特性对中性层的影响相对不明显。此外,压电层与芯层之间的层间应力可以增加或减少,这取决于外加电压比和双模态比的相对大小。所获得的结果有助于分析机电耦合机制和设计具有双模块特性的压电复合材料和结构。
Anisotropy Behavior of Liquid Metal Elastomer Composites with Both Enhanced Thermal Conductivity and Crack Resistance by Direct Ink Writing
Xu Peihua, Zhu Lida, Zhao Zixu, Yang Zhichao, Ning Jinsheng, Xue Pengsheng, Lu Hao
doi:10.1016/j.compositesa.2023.107890
通过直接油墨写入法增强导热性和抗裂性的液态金属弹性体复合材料的各向异性行为
Liquid metal elastomer composites (LMEC) have broad application prospects in flexible devices, but the research on the basic processes of DIW for LMEC and the properties of DIW-ed LMEC is lacking. In this study, liquid metal (LM) is added to silicone elastomers such as Polydimethylsiloxane (PDMS), and the effect of LM volume fraction on ink rheology is investigated. Results show that the storage modulus of ink is lower than its loss modulus, which is not conducive to self-support formation. Therefore, fluorination is adopted to treat the silicon dioxide substrate used, thereby reducing the deformation rate of the printed structure to below 110%. The results of properties show that the crack resistance and thermal conductivity of soft elastomers increase with the LM volume fraction. Additionally, the tensile properties of PDMS printed via DIW exhibit significant anisotropy parallel and perpendicular to the scanning direction, and that the addition of LM droplets reduces the anisotropy. And with the increase of curing temperature and LM droplet size, the stretchability of DIW-ed LMEC in both directions decreases, but only LMEC samples cured at 140℃ exhibit significant anisotropy. This study provides guidance pertaining to the basic process and printing directions for the application of DIW in the manufacture of LMEC equipment.
液态金属弹性体复合材料(LMEC)在柔性设备中具有广阔的应用前景,但有关液态金属弹性体复合材料 DIW 的基本工艺以及 DIW 后液态金属弹性体复合材料性能的研究却十分缺乏。本研究将液态金属(LM)添加到聚二甲基硅氧烷(PDMS)等有机硅弹性体中,并研究了 LM 体积分数对油墨流变性的影响。结果表明,油墨的存储模量低于其损耗模量,不利于自支撑的形成。因此,采用氟化处理所用的二氧化硅基底,从而将印刷结构的变形率降低到 110% 以下。性能结果表明,软弹性体的抗裂性和导热性随 LM 体积分数的增加而提高。此外,通过 DIW 印刷的 PDMS 的拉伸性能在平行和垂直于扫描方向上表现出明显的各向异性,而添加 LM 液滴则会降低这种各向异性。随着固化温度和 LM 液滴大小的增加,DIW 印刷的 LMEC 在两个方向上的拉伸性都会降低,但只有在 140℃ 下固化的 LMEC 样品才会表现出明显的各向异性。这项研究为在 LMEC 设备制造中应用 DIW 的基本工艺和印刷方向提供了指导。
Evolutionary Algorithm-Based Integrated Design of Material-Structural Microwave Absorption Using Material Extrusion
Zhang Yuhui, Shan Mengtong, Lei Han, Zhao Pengzhen, Yu Chen, Huang Yixing
doi:10.1016/j.compositesa.2023.107891
基于进化算法的材料-结构微波吸收综合设计(材料挤压法
The development of electromagnetic wave absorbing materials and structures holds significant importance in fields such as aerospace and electronic communications. Traditional absorbing coatings have poor mechanical load-bearing capacity and struggle to meet the requirements of lightweight applications. On the other hand, the research on lossy dielectric absorbers is limited by process constraints, making it difficult to fabricate complex configurations, thereby greatly restricting their broadband absorption performance. In this study, a functional absorbing composite filament was developed using material extrusion technique. A magnetic lossy four-layer gradient honeycomb metastructure was designed, which enables effective absorption in the frequency range of 6.09-37.18 GHz within a thickness of 16 mm. The effective absorption bandwidth covers 81.82% in the frequency range of 2-40 GHz. This broadband absorbing design achieves the integration of material functionality and structural design by additive manufacturing, enabling effective absorption across a broad frequency range.
电磁波吸收材料和结构的开发在航空航天和电子通信等领域具有重要意义。传统的吸波涂层机械承载能力差,难以满足轻质应用的要求。另一方面,有损电介质吸收体的研究受到工艺限制,难以制造复杂的结构,从而大大限制了其宽带吸收性能。本研究利用材料挤压技术开发了一种功能性吸波复合丝。设计了一种磁性损耗四层梯度蜂窝结构,在厚度为 16 毫米的范围内实现了 6.09-37.18 GHz 频率范围内的有效吸收。在 2-40 GHz 频率范围内,有效吸收带宽达到 81.82%。这种宽带吸收设计通过增材制造实现了材料功能与结构设计的整合,从而实现了宽频率范围内的有效吸收。
Hybrid assembly based on nanomaterial reinforcement for multifunctionalized skin-like flexible sensors
Lv Xiaohua, Ling Yufei, Tang Kaiyou, Qiao Changyu, Fu Lihua, Xu Chuanhui, Lin Baofeng, Wei Yen
doi:10.1016/j.compositesa.2023.107892
基于纳米材料加固的混合组件,用于多功能类肤柔性传感器
Currently, the inferior mechanical strength, weak environmental adaptability, and limited functionality of conductive hydrogel significantly impede its potential application in wearable sensors. Here, ''hard'' acrylic bentonite (AABT) intercalated nanostructures and silver-modified polydopamine (PDA@Ag) particles are encapsulated in a ''soft'' polyacrylic acid matrix in a water/glycerol binary solvent system. This strategy successfully realized the high matched skin modulus (58 kPa), high stress (371 kPa) and strain (1025%). The PDA@Ag particles retains rich phenolic hydroxyl groups imitating mussel to provide strong adhesion (29.12 kPa). These particles also give the hydrogel long time antibacterial properties (3 days), while demonstrating excellent biosafety. The introduction of a binary system of water/glycerol effectively suppresses the evaporation and crystallization of water, thereby maintaining sensing performance above 82% even under extreme conditions. This hydrogel achieves integrated applications of multifunctionality and multi-environmental adaptability, providing a new idea for the development of next-generation skin-like hydrogel sensors.
目前,导电水凝胶的机械强度低、环境适应性弱、功能有限,这些都严重阻碍了其在可穿戴传感器中的潜在应用。在这里,"硬 "丙烯酸膨润土(AABT)插层纳米结构和银改性聚多巴胺(PDA@Ag)颗粒被封装在水/甘油二元溶剂体系中的 "软 "聚丙烯酸基质中。这种策略成功实现了高匹配表皮模量(58 kPa)、高应力(371 kPa)和应变(1025%)。PDA@Ag 颗粒保留了仿贻贝的丰富酚羟基,提供了强大的粘附力(29.12 kPa)。这些颗粒还赋予了水凝胶长效抗菌特性(3 天),同时表现出卓越的生物安全性。水/甘油二元体系的引入有效抑制了水的蒸发和结晶,因此即使在极端条件下也能保持 82% 以上的传感性能。这种水凝胶实现了多功能和多环境适应性的综合应用,为开发下一代类皮肤水凝胶传感器提供了新思路。
Dual-modulus 3D Printing Technology for Magnetorheological Metamaterials-Part II: Negative Regulation Theory and Application
Lou Congcong, Liu Bing, Cao Xufeng, Gao Liang, Xuan Shouhu, Deng Huaxia, Gong Xinglong
doi:10.1016/j.compositesa.2023.107893
磁流变超材料的双模量三维打印技术--第二部分:负调控理论与应用
Metamaterials are artificially structured periodic materials that have remarkable property of wave attenuation in bandgaps. However, metamaterials with adjustable and low-frequency bandgap are still challenge in traditional method. In this work, a novel magnetorheological metamaterial (MRM) with negative regulation and low-frequency bandgaps was fabricated by dual-modulus 3D printing technology. The bandgaps of negative regulation MRM were analyzed theoretically by using the mass-spring model. As a result, the starting frequency of bandgap reduced by 37.6% and ending frequency increased by 47.8% under external magnetic field. Moreover, the propagation characteristics of longitudinal wave in negative regulation MRM were also studied and the results indicated that the stiffnesses were magnetic-related, and the bandgap can be tuned substantially under external magnetic field. This work presented a negative regulation MRM that the bandgap was broadened and moved to lower frequency under the external magnetic field, showing a great potential in the field of vibration isolation.
超材料是一种人工结构的周期性材料,在带隙中具有显著的波衰减特性。然而,具有可调低频带隙的超材料仍然是传统方法的挑战。在这项工作中,利用双模量三维打印技术制作了一种具有负调控和低频带隙的新型磁流变超材料(MRM)。利用质量弹簧模型对负调节超材料的带隙进行了理论分析。结果表明,在外加磁场作用下,带隙的起始频率降低了 37.6%,终止频率提高了 47.8%。此外,还研究了负调压磁共振中纵波的传播特性,结果表明刚度与磁有关,带隙在外加磁场作用下可大幅调整。这项研究提出了一种负调控磁共振,其带隙在外加磁场的作用下被拓宽并向低频移动,在隔振领域显示出巨大的潜力。
Recycled carbon fiber potential for reuse in carbon fiber/PA6 composite parts
Jeantet Louis, Regazzi Arnaud, Perrin Didier, Pucci Monica Francesca, Corn Stéphane, Quantin Jean-Christophe, Ienny Patrick
doi:10.1016/j.compositesb.2023.111100
再生碳纤维在碳纤维/PA6 复合材料部件中的再利用潜力
Pyrolysis reclaiming is the most promising process to treat high volumes of composite waste with an advantageous carbon footprint. This paper aims to compare pyrolysis reclaimed carbon fibers (RCF) to virgin sized fibers (VF) and de-sized fibers (VFT) in their capability to bond to a polyamide 6 matrix. Micromechanical tensile testing of single fiber samples of the three fiber types was conducted. A minor reduction in tensile strength and an unchanged elastic modulus of the RCF compared to VF was observed. Scanning electron microscopy and atomic force microscopy scans were used to evaluate the morphology of the fibers. To evaluate the surface energy of the fibers, tensiometric testing was conducted. RCF showed a better adhesion capability compared to VFT through higher total surface energy. Moreover, X-ray spectrophotometry scans highlighted a higher proportion of functional groups at the RCF surface compared to VFT. Finally, pull-out tests underlined a decrease of the interfacial shear strength of RCF and VFT by 35 % compared to VF. Overall, this study’s results further the understanding of the impact of the pyrolysis reclaiming process on RCF mechanical and adhesion properties.
热解再生是处理大量复合材料废料的最有前途的工艺,同时还具有良好的碳足迹。本文旨在比较热解再生碳纤维(RCF)与原生尺寸纤维(VF)和去尺寸纤维(VFT)与聚酰胺 6 基质的粘合能力。对三种纤维的单纤维样品进行了微机械拉伸测试。与 VFT 相比,RCF 的拉伸强度略有降低,弹性模量保持不变。扫描电子显微镜和原子力显微镜扫描用于评估纤维的形态。为了评估纤维的表面能,还进行了张力测试。与 VFT 相比,RCF 通过更高的总表面能显示出更好的粘附能力。此外,X 射线分光光度扫描显示,与 VFT 相比,RCF 表面的官能团比例更高。最后,拉出试验表明,与 VF 相比,RCF 和 VFT 的界面剪切强度降低了 35%。总之,这项研究的结果进一步加深了人们对热解再生工艺对 RCF 机械和粘附性能影响的理解。
A simple rheological method for the experimental assessment of the fiber percolation threshold in short fiber biocomposites
Vitiello Libera, Salzano de Luna Martina, Ambrogi Veronica, Filippone Giovanni
doi:10.1016/j.compscitech.2023.110345
用于实验评估短纤维生物复合材料纤维渗流阈值的简单流变学方法
The identification of the percolation threshold (Φc) in short fiber composites is a challenging problem in Composite Science. Above Φc the fibers form a continuous network that causes substantial changes in mechanical and transport properties. Besides, percolation of natural fibers in biodegradable polymer matrices allows water and other pro-degradative species to access the inner parts of the material from the external environment, accelerating biodegradation. Whether such a speeding up is desired or not, assessing Φc in composites is of utmost importance. Unfortunately, natural fibers are not conductive and exhibit highly variable shape and physical properties. This prevents the use of many experimental and theoretical approaches for the estimate of Φc. Here we propose an original rheological approach borrowed from the viscoelastic modelling of polymer nanocomposites. The method was applied to two systems made of poly(lactic acid) filled with hemp or kenaf fibers (average length <500 μm, average length-to-diameter ratio <5). The estimate of Φc (∼10.1 and 19.5 vol% for the hemp- and kenaf-based composite, respectively) required a single set of simple linear viscoelastic measurements, and the computed values were in good agreement with those obtained through time-consuming (measurement times >3 weeks) dielectric spectroscopy analyses (∼10.1 and 18.5 vol%).
确定短纤维复合材料中的渗流阈值(Φc)是复合材料科学中一个具有挑战性的问题。超过 Φc 时,纤维会形成连续的网络,从而导致机械和传输性能发生重大变化。此外,天然纤维在可生物降解聚合物基质中的渗滤作用可使水和其他促降解物质从外部环境进入材料内部,从而加速生物降解。无论是否希望加速降解,评估复合材料中的Φc 都至关重要。遗憾的是,天然纤维并不导电,而且其形状和物理性质变化很大。这使得许多实验和理论方法无法用于估算 Φc。在此,我们从聚合物纳米复合材料的粘弹性建模中借鉴了一种独创的流变学方法。我们将该方法应用于由聚乳酸填充麻纤维或槿麻纤维(平均长度小于 500 μm,平均长径比小于 5)制成的两个系统。只需进行一组简单的线性粘弹性测量,即可估算出Φc(麻基和槿麻基复合材料的Φc分别为 10.1 ∼ 10.1 和 19.5 vol%),计算值与耗时(测量时间大于 3 周)的介电光谱分析结果(Φc 为 10.1 ∼ 10.1 和 18.5 vol%)十分吻合。