今日更新:Composite Structures 4 篇,Composites Part A: Applied Science and Manufacturing 3 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Structural topology optimization of three-dimensional multi-material composite structures with finite deformation
Du Zongliang, Guo Yunhang, Liu Chang, Zhang Weisheng, Xue Riye, Guo Yilin, Tang Shan, Guo Xu
doi:10.1016/j.compstruct.2023.117692
有限变形三维多材料复合结构拓扑优化
In this work, an explicit three-dimensional (3D) topology optimization approach is presented for multi-material composite structures accounting the finite deformation effect. The proposed method employs different sets of 3D Moving Morphable Voids (MMVs) to identify each phase material, resulting in explicit geometric descriptions of the optimized composite structures and a reduction in the number of design variables. The decoupling between the topology description and finite element analysis of composite structures enables the removal of redundant degrees of freedom, thereby mitigating the convergence issue of finite deformation analysis caused by low-density elements and leading to significant computational savings. Numerical experiments of composite structures with two- and three-phase materials are optimized to validate the accuracy and efficiency of the proposed method. The results demonstrate that, under finite deformation, the distribution of each phase material in optimized 3D composite structures is significantly affected by the amplitude of external loads, and the optimized layout could be quite different from its counterpart under small deformation assumption.
在这项工作中,提出了一种考虑有限变形效应的多材料复合材料结构显式三维(3D)拓扑优化方法。该方法采用不同的3D移动可变形空洞(mmv)集 合来识别每个相材料,从而对优化后的复合材料结构进行明确的几何描述,减少了设计变量的数量。复合材料结构的拓扑描述与有限元分析之间的解耦能够消除冗余自由度,从而减轻由低密度单元引起的有限变形分析的收敛问题,从而显著节省计算量。通过两相和三相材料复合结构的数值实验,验证了该方法的准确性和有效性。结果表明,在有限变形条件下,优化后的三维复合材料结构中各相材料的分布受外载荷幅值的影响较大,且优化后的布局与小变形条件下的布局存在较大差异。
Bandgap regulations of longitudinal wave for a nonlinear metastructure isolator with high-static-low-dynamic stiffness
Chen Ning, Yang Zhichun, Zuo Ang, Jiang Pengfei, Jin Shikai, Xu Yanlong
doi:10.1016/j.compstruct.2023.117706
高静低动刚度非线性元结构隔振器纵波带隙规律
Linear structures are inherently difficult to exhibit mechanical properties with high-static-low-dynamic stiffness (HSLDS), which means that linear isolators with these structures struggle to have both high-quality load-bearing capacity and low-frequency isolation ability at the same time. To address this issue, we have designed a high-load-capacity local resonance (LR) nonlinear metastructure isolator for low-frequency vibration isolation of target objects. We reveal the regulation mechanism of longitudinal wave attenuation in such metastructures and conduct comparative study by finite element method (FEM) and experiments for a 3D printed prototype metastructure. The results show that in specific excitation frequencies, the LR nonlinear metastructure with a cantilever beam oscillator having a natural frequency of 11.7 Hz triggers a LR mechanism. Under the action of the nonlinear isolator, the vibration transmissibility is as low as 10% at the center frequency of the bandgap under the base excitation. Furthermore, the dispersion equation of such nonlinear metastructures is derived, and through the analysis of the regulation of bandgaps, the variation trend of the transmissibility of nonlinear metastructure isolators is effectively predicted. The calculation method and design idea of this metastructure isolators provide a new approach for vibration isolation.
线性结构本身就很难表现出高静低动刚度(HSLDS)的力学性能,这意味着这些结构的线性隔振器很难同时具有高质量的承载能力和低频隔振能力。为了解决这一问题,我们设计了一种高负载能力局部共振(LR)非线性元结构隔振器,用于目标物体的低频隔振。我们揭示了这种元结构中纵波衰减的调节机制,并通过三维打印原型元结构的有限元方法(FEM)和实验进行了对比研究。结果表明,在特定的激励频率下,具有固有频率为11.7 Hz的悬臂梁振子的LR非线性元结构触发LR机制。在非线性隔振器的作用下,在基极激励下,在带隙中心频率处,振动透射率低至10%。进一步推导了非线性元结构的色散方程,通过分析带隙的变化规律,有效地预测了非线性元结构隔振子的透射率变化趋势。这种元结构隔振器的计算方法和设计思想为隔振提供了一种新的途径。
Simulation of failure behavior of 2.5D SiC/SiC variable thickness dovetail joint structures based on mesoscale model
Zhang Sheng, Liu Chenyang, Zhang Xu, Du Jinkang, Chen Qiang, Gao Xiguang, Song Yingdong
doi:10.1016/j.compstruct.2023.117716
基于中尺度模型的2.5D SiC/SiC变厚度燕尾接头破坏行为模拟
The application of ceramic matrix composites plays an important role in improving the performance of aero engines. However, mesoscopic aperiodicity causes excellent challenges for the performance analysis of ceramic matrix composite structures. It is no longer applicable to obtain the macroscopic properties of materials through experiments or RVE simulations for structural performance analysis. Here an attempt is made to develop a performance analysis method for mesoscopic aperiodic ceramic matrix composite structures based on mesoscale models and apply the method to the strength calculation of 2.5D SiC/SiC variable thickness dovetail joint structures. The established model reasonably approximates and accurately describes the structure’s real yarn geometries and orientations, reflecting the differences of yarn architectures in different regions. The yarn stress–strain curve is obtained through experiments, and the yarn constitutive model is established. The failure behavior of the 2.5D woven dovetail joint structure is simulated using the progressive damage analysis method and taking the yarn as the basic load-bearing unit. The simulated results are in good agreement with the experimental data in terms of failure load, load–displacement responses, macroscopic damage evolutions, and failure modes.
陶瓷基复合材料的应用对提高航空发动机的性能起着重要的作用。然而,介观非周期性给陶瓷基复合材料结构的性能分析带来了极大的挑战。通过实验或RVE模拟来获得材料的宏观性能已不再适用于结构性能分析。本文尝试建立一种基于细观尺度模型的介观非周期陶瓷基复合材料结构性能分析方法,并将该方法应用于2.5D SiC/SiC变厚度燕尾接头结构的强度计算。所建立的模型合理地逼近和准确地描述了结构的真实纱线几何形状和方向,反映了不同地区纱线结构的差异。通过实验得到了纱线的应力应变曲线,建立了纱线的本构模型。采用渐进式损伤分析方法,以纱线为基本承载单元,模拟了2.5维编织燕尾节点结构的破坏行为。在破坏荷载、荷载-位移响应、宏观损伤演化和破坏模式等方面,模拟结果与试验数据吻合较好。
A mechanical analysis of variable angle-tow composite plates through variable kinematics models based on Carrera’s unified formulation
Iannotta D.A., Giunta G., Montemurro M.
doi:10.1016/j.compstruct.2023.117717
基于Carrera统一公式的可变运动学模型对变角-拖曳复合材料板的力学分析
Variable Angle-Tow (VAT) laminates offer a promising alternative to straight fiber composites. By varying fibers orientation within the structure plane, ambitious design and performance goals can be achieved. However, the wider design space results in a more complex problem with more parameters to consider. Carrera’s Unified Formulation (CUF) has been used in previous works performing buckling, vibrational and stress analyses of VAT plates. Usually, one-dimensional (1D) CUF beam models are used, while two-dimensional (2D) plate models are obtained as a particular case of shells by considering a null curvature. In most cases, a linear law is considered to describe the variation of fibers orientation in the main plane of the structure. The purpose of this article is to extend the CUF 2D plate finite elements family to the mechanical analysis of composite laminated plate structures with curvilinear fibers. The main contribute consists in the development of a CUF FE model within the Reissner’s Mixed Variational Theorem (RMVT) context for an improved calculation of the out-of-plane stress components. Results show that RMVT can predict in-plane stresses and satisfy the though-the-thickness transverse stresses continuity due to inter-layer equilibrium. The accuracy of RMVT-based models is also investigated using two different approximation points distributions along the plates thickness.
可变角束(VAT)层压板提供了一种有前途的替代直纤维复合材料。通过改变纤维在结构平面内的取向,可以实现雄心勃勃的设计和性能目标。然而,更宽的设计空间导致了更复杂的问题,需要考虑更多的参数。Carrera的统一公式(CUF)已在以前的工作中用于VAT板的屈曲,振动和应力分析。通常使用一维(1D) CUF梁模型,而考虑零曲率的壳的特殊情况下,得到二维(2D)板模型。在大多数情况下,考虑线性定律来描述纤维取向在结构主平面上的变化。本文的目的是将CUF二维板有限元族扩展到曲线纤维复合材料层合板结构的受力分析。主要贡献在于在Reissner的混合变分定理(RMVT)背景下开发了CUF有限元模型,用于改进面外应力分量的计算。结果表明,由于层间平衡,RMVT可以预测面内应力,并满足横向应力的纵贯连续性。利用两种不同的近似点沿板厚分布,研究了基于rmvt的模型的精度。
Displacement-reconstruction-realized components by structure-sensing integration via a hybrid 3D printing strategy
Tao Yin, Yu Peishi, Zhang Xin, Li Maoyang, Liu Tao, Zhao Junhua
doi:10.1016/j.compositesa.2023.107896
基于混合3D打印策略的结构传感集成实现位移重建组件
Realizing displacement reconstruction is one of the main goals of real-time intelligent monitoring systems, motivating a highly promising requirement for structure-sensing integration technology. To obtain displacement-reconstruction-realized components, the crucial challenges cover the whole process including sensor-layout design, sensor assembly and rapidly functional verification. Accordingly, a rapid iterative solution is proposed from sensor-layout optimization to structure-sensing integrated fabrication then to displacement-reconstruction realization. A sensor array is optimally designed with minimized unit number and simplified circuit layout to integrate on the surface of or embed into the structures. Then we combine the direct-ink-writing with fused deposition modeling, achieving hybrid 3D printing strategy to fabricate the structure-sensing integrated components within one step. The local strains of plates are detected by the sensors and their full-field displacements are then reconstructed without any loading information. This work provides insights into the design and fabrication of structure–function-integration structures or devices.
实现位移重建是实时智能监测系统的主要目标之一,这激发了对结构传感集成技术的高度发展需求。为了获得实现位移重建的元件,关键的挑战涵盖了整个过程,包括传感器布局设计,传感器组装和快速功能验证。据此,提出了从传感器布局优化到结构传感集成制造再到位移重建实现的快速迭代求解方法。以最小的单元数和简化的电路布局优化设计传感器阵列,使其集成在结构表面或嵌入结构中。然后,我们将直墨书写与熔融沉积建模相结合,实现了混合3D打印策略,在一步内制造出结构传感集成组件。传感器检测板的局部应变,然后在没有任何载荷信息的情况下重建板的全场位移。这项工作为结构-功能-集成结构或器件的设计和制造提供了见解。
Phosphonitrile-modified biomass multi-crosslinking strategy: Construction of flame retardant, smoke suppressive and antibacterial polyvinyl alcohol composites
Tan Wei, Gao Lixiao, Su Jingna, Zuo Chunlong, Ren Yuanlin, Liu Xiaohui
doi:10.1016/j.compositesa.2023.107897
磷腈改性生物质多交联策略:阻燃、抑烟、抗菌聚乙烯醇复合材料的构建
To solve the problems of flammability, large smoke production and easy breeding of bacteria, polyvinyl alcohol (PVA) was modified by a multi-crosslinking structure fabricated by hexachlorocyclotriphosphazene derivative (SHCP) and chitosan (CS) followed by copper ions chelation. In terms of flame retardancy, the peak heat release rate (PHRR) and total heat release (THR) of the modified PVA composites decreased by 52.38% and 24.22%, while the LOI value and char-forming ability were greatly improved. The total smoke production (TSP) of the treated sample decreased by 91.00%. Furthermore, the inhibition rate of modified PVA composites against E. coli and S. aureus was as high as 99.67% and 92.45%. The current work provided a sustainable and versatile advanced strategy for the design of environmentally friendly, and cost-effective flame retardant, smoke suppression and antibacterial PVA composites, which was expected to be applied in the packaging field.
为解决聚乙烯醇(PVA)易燃、产烟大、易滋生细菌等问题,采用六氯环三磷腈衍生物(SHCP)与壳聚糖(CS)复合制备多交联结构对聚乙烯醇(PVA)进行了铜离子螯合改性。在阻燃性方面,改性后的PVA复合材料的峰值放热率(PHRR)和总放热率(THR)分别降低了52.38%和24.22%,LOI值和成炭能力均有较大提高。处理后样品的总产烟量(TSP)降低了91.00%。改性PVA复合材料对大肠杆菌和金黄色葡萄球菌的抑制率分别高达99.67%和92.45%。本研究为设计环保、高性价比的阻燃、抑烟、抗菌聚乙烯醇复合材料提供了一种可持续、通用的先进策略,有望在包装领域得到应用。
Surface waviness of continuous fiber-reinforced thermosets – Experimental and numerical studies considering the viscoelasticity of the resin
Lorenz N., Hennes P., Fischer K., Hopmann Ch.
doi:10.1016/j.compositesa.2023.107895
连续纤维增强热固性材料的表面波纹度。考虑树脂粘弹性的实验和数值研究
This contribution aims to understand surface waviness formation during cooling and post-curing of glass fiber-reinforced plastics (GFRP). GFRP plates were manufactured by resin transfer molding (RTM). Part surface waviness is determined by tactile contour measuring at ambient temperature up to 1008h after initial cooling. Additionally, the manufactured plates were exposed to elevated post-curing temperatures to study the influence of resins’ viscoelasticity on their surface waviness. In parallel, the curing and post-curing processes were analyzed using a cure- and temperature-dependent viscoelastic simulation model. The experimental results of this work capture the influence of the resin’s viscoelastic behavior on the surface waviness at ambient and temperatures. The numerical results show a satisfactory agreement with experimental values. Surface waviness amplitude increases up to 25% for the applied post-curing cycle. The results of the present work underline the importance of the resin’s temperature-dependent viscoelasticity on the process-related formation of surface waviness.
这一贡献旨在了解玻璃纤维增强塑料(GFRP)在冷却和后固化过程中的表面波纹形成。采用树脂传递模塑(RTM)法制备玻璃钢板材。零件表面波纹度是在初始冷却后1008h的环境温度下通过触觉轮廓测量确定的。此外,将制备的板材暴露在较高的固化后温度下,研究树脂的粘弹性对其表面波纹度的影响。同时,利用依赖于固化和温度的粘弹性模拟模型对固化和后固化过程进行了分析。本工作的实验结果捕捉到树脂的粘弹性行为对环境和温度下表面波纹的影响。数值计算结果与实验值吻合较好。在应用后固化周期时,表面波纹幅度增加到25%。本工作的结果强调了树脂的温度依赖粘弹性在表面波纹的工艺相关的形成的重要性。
Morphological characteristics of spray dried cellulose nanofibers produced using various wood pulp feedstocks and their effects on polypropylene composite properties
Hwang Sungjun, Han Yousoo, Gardner Douglas J.
doi:10.1016/j.compositesb.2023.111093
不同木浆原料制备的喷雾干燥纤维素纳米纤维的形态特征及其对聚丙烯复合材料性能的影响
Bleached Kraft pulp (BKP), unbleached Kraft pulp (UKP), and old corrugated cardboard pulp (OCC) are excellent feedstock sources for producing CNF suspensions manufactured by a mechanical disk refining process. The CNF drying operation should be performed to produce dry powders that can be compounded into thermoplastic matrices, and spray drying is fast, simple, cost-effective, and scalable. Among several spray-drying techniques, the pilot scale-rotary disk atomizer has many advantages, including large capacities, drying efficiency, and less feed blockage. In this study, BKP, UKP, and OCC pulps fibrillated to 90 % and 100 % fines levels were spray-dried using a pilot-scale rotary disk atomizer. The high-quality micrometer scale, round-shaped powders were produced from all feedstock sources, and a smaller particle size powder was produced with the higher fibrillated pulps. The spray-dried cellulose nanofibrils (SDCNFs) were compounded into a polypropylene (PP) matrix as a reinforcing material, and maleic anhydride-grafted polypropylene (MAPP) was used as a coupling agent. A masterbatch was used for the optimal dispersion and distribution of SDCNFs and MAPP in the PP matrix. It was concluded that the tensile and flexural properties increased as the particle size of SDCNFs increased, and the impact strength increased as the particle size decreased. The tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength increased by up to 29 %, 66 %, 15 %, 27 %, and 11 % respectively, compared to the neat PP after adding 10 wt% of SDCNFs with MAPP to the PP matrix.
漂白硫酸盐纸浆(BKP),未漂白硫酸盐纸浆(UKP)和旧瓦楞纸板纸浆(OCC)是生产CNF悬浮液的优良原料,由机械圆盘精炼过程制造。CNF干燥操作应执行以生产可复合成热塑性基质的干燥粉末,喷雾干燥快速,简单,具有成本效益和可扩展性。在几种喷雾干燥技术中,中试规模旋转圆盘雾化器具有容量大、干燥效率高、进料堵塞少等优点。在这项研究中,BKP, UKP和OCC纸浆纤原化到90% %和100% %的细粉水平,使用中试规模的旋转圆盘雾化器喷雾干燥。所有原料均可制得高质量的微米级圆形粉体,高纤原化浆可制得小粒度粉体。将喷雾干燥的纤维素纳米原纤维(SDCNFs)复合成聚丙烯(PP)基体作为增强材料,以马来酸酐接枝聚丙烯(MAPP)作为偶联剂。采用母粒对SDCNFs和MAPP在PP基质中的分散和分布进行了优化。结果表明,SDCNFs的拉伸和弯曲性能随粒径的增大而增大,冲击强度随粒径的减小而增大。在PP基体中加入10 wt%的MAPP后,与纯PP相比,拉伸强度、拉伸模量、弯曲强度、弯曲模量和冲击强度分别提高了29 %、66 %、15 %、27 %和11 %。
Interfacial thermal conduction mechanism of polypyrrole/carbon nanotube composites
Zou Hanying, Feng Yanhui, Tang Xiaolong, Zhang Xinxin, Qiu Lin
doi:10.1016/j.compscitech.2023.110346
聚吡咯/碳纳米管复合材料界面热传导机理研究
The excellent properties of carbon nanotube (CNT) make it possible for CNT-based materials to have both high thermal conductivity and high electrical conductivity. However, the weak coupling between the CNTs results in these properties far below expectations, which seriously hinders the application of CNT-based materials. The approaches to improve the electrical conductivity or the thermal conductivity are usually considered separately, but the heat generated by low resistance at high frequencies cannot be ignored and both of them need be focused. Loading polypyrrole (PPy) into the grooves between CNTs is a common method to improve electrical conductivity of CNT-based materials, which may also increase thermal conductivity through its polymer characters. This work finds that PPy fills the space of the grooves between CNTs, acts as the role of thermal transport relay, and builds a more stable heat transfer channel. And the PPy also resonates with carbon atoms, results in the phonon mode variation and interfacial phonon mismatch level change. The interfacial thermal conduction of CNTs significantly improves up to 202 %. This provides new design ideas for advanced CNT-based electronic devices.
碳纳米管的优异性能使碳纳米管基材料具有高导热性和高导电性成为可能。然而,碳纳米管之间的弱耦合导致这些性能远低于预期,这严重阻碍了碳纳米管基材料的应用。提高电导率的方法和提高导热性的方法通常是分开考虑的,但在高频下低电阻产生的热量是不可忽视的,两者都需要关注。在碳纳米管之间的沟槽中加载聚吡咯(PPy)是提高碳纳米管基材料导电性的常用方法,也可能通过其聚合物特性提高导热性。本研究发现,PPy填充了CNTs之间的凹槽空间,起到了热传递中继的作用,建立了更稳定的传热通道。PPy还与碳原子发生共振,导致声子模式的变化和界面声子失配水平的变化。CNTs的界面热传导率显著提高202%。这为基于碳纳米管的先进电子器件提供了新的设计思路。