今日更新:Composite Structures 2 篇,Composites Part B: Engineering 3 篇
Characterizing the flexural/damage behavior of Aluminosilicate glass at low/high loading rates: Application of SHPB for mode-1 loading of laminated glass
Muhammad Aamir Raza, Suo Tao, Penghao Pei, Uzair Ahmed Dar, M. Atif, Muhammad Zakir Sheikh, Guozhong Gao, Zhongbin Tang
doi:10.1016/j.compstruct.2023.117816
低/高加载率下铝硅酸盐玻璃的弯曲/损伤行为表征:SHPB在夹层玻璃1型加载中的应用
Understanding the flexural response of monolithic and laminated glass is essential for making informed choices while selecting glass for varying applications. That is because the behavior of monolithic and laminated glass may not necessarily be the same under certain loading conditions and assessing their performance differences helps in determining their suitability for specific applications. The presented work is aimed at quantifying the flexural/damage behavior of monolithic and laminated glass. Quasi-static and dynamic flexural tests were conducted on monolithic and laminated glass in mode-1 loading while maintaining identical loading and support interfaces. In the first phase, quasi-static flexural tests were performed, and results were quantitatively compared by two approaches: Effective Thickness Approximation (ETA) and the theory of Thick Sandwiched Beams (TSB). Experimentally observed deflection corroborated with both the analytical methods; the absolute error remained less than 2.5% and 0.5% for ETA and TSB, respectively. Importantly, failure of the laminate was witnessed at approximately 50% lower force compared to its monolithic counterpart, which was attributed to the span length of the specimen and the interlayer’s shear stiffness. Fractography was performed to elicit Aluminosilicate glass’s mirror constant and fracture surface energy, as 1.86 MN/m3/2 and 3.95 J/m2, respectively. In Phase-2, Dynamic flexural tests were conducted on a novel Electromagnetic Split Hopkinson Pressure Bar (ESHPB), and an experimental-numerical coupled approach was introduced to analyze the results. The results established that the adverse effects of shorter span length on the flexural strength of laminated glass are mitigated, primarily due to the viscoelastic response of the interlayer. The reprographic images attributed the fracture of monolithic and laminated glass specimens solely to the bending-induced stresses.
了解单片和夹层玻璃的弯曲响应对于在选择不同应用的玻璃时做出明智的选择至关重要。这是因为在特定的载荷条件下,单片玻璃和夹层玻璃的性能不一定相同,评估它们的性能差异有助于确定它们在特定应用中的适用性。所提出的工作旨在量化单片和夹层玻璃的弯曲/损伤行为。在保持相同加载界面和支撑界面的情况下,对单片玻璃和夹层玻璃进行了模一加载下的准静态和动态弯曲试验。在第一阶段,进行了准静态弯曲试验,并通过有效厚度近似(ETA)和厚夹层梁理论(TSB)两种方法对结果进行了定量比较。实验观察到的挠度与两种分析方法一致;ETA和TSB的绝对误差分别小于2.5%和0.5%。重要的是,层压板的破坏是在大约50%的低力下发生的,这是由于试件的跨度长度和夹层的剪切刚度。通过断口分析,得出了硅酸铝玻璃的镜面常数和断口表面能分别为1.86 MN/m3/2和3.95 J/m2。在第二阶段,对新型电磁分离式霍普金森压杆(ESHPB)进行了动态弯曲试验,并引入实验-数值耦合方法对试验结果进行了分析。结果表明,较短的跨度长度对夹层玻璃抗弯强度的不利影响得到了缓解,这主要是由于夹层的粘弹性响应。复 制图像将单片和夹层玻璃试样的断裂完全归因于弯曲引起的应力。
NUMERICAL AND EXPERIMENTAL ASSESSMENT OF OPTIMAL MODELING OF LAMINATED GLASS POST-BREAKAGE RESPONSE
Moheldeen Hejazi, Ali Sari
doi:10.1016/j.compstruct.2023.117822
夹层玻璃破碎后响应优化模型的数值与实验评价
Modeling laminated glass response to extreme loading scenarios is a computationally demanding process in designing and analyzing protective structures. Therefore, an optimal modeling scheme requires a delicate trade-off between accuracy and computational demand. This article investigates the failure modeling of laminated glass layups of thin and thick panels (three and 11 layers) under blast loading. This is done by implementing various simulation techniques: the finite element method with element erosion/deletion, the mesh-free method of smoothed particle hydrodynamics, and the hybrid implementation of mesh-based and mesh-free simulation through element conversions into particles. This Article examines the feasibility and limitations of each method, considering both the aspects of accuracy and computational cost in light of experimental testing results obtained from both arena and shock tube scenarios. Mesh sensitivity and the significance of adaptive meshing in capturing the fracture patterns are evaluated. The present paper suggests that using hybrid techniques leads to optimal modeling results. Furthermore, the stability of the modeling results under diverse blast conditions is verified.
在设计和分析防护结构时,模拟夹层玻璃在极端载荷情况下的响应是一个计算要求很高的过程。因此,最优的建模方案需要在精度和计算需求之间进行微妙的权衡。本文研究了爆炸荷载作用下薄板和厚板(3层和11层)夹层玻璃层合结构的破坏模型。这是通过实现各种模拟技术来实现的:具有单元侵蚀/缺失的有限元方法,光滑颗粒流体动力学的无网格方法,以及通过将元素转换为颗粒的基于网格和无网格模拟的混合实现。本文考察了每种方法的可行性和局限性,根据竞技场和激波管场景的实验测试结果,考虑了准确性和计算成本两方面。评估了网格敏感性和自适应网格在捕获断裂模式中的意义。本文认为,采用混合技术可以获得最佳的建模结果。进一步验证了模型在不同爆炸条件下的稳定性。
Mechanical behaviors of three-dimensional chiral mechanical metamaterials
Tiantian Li, Yaning Li
doi:10.1016/j.compositesb.2023.111141
三维手性机械超材料的力学行为
Chiral and achiral mechanical metamaterials are designed via spherical tiling. The 3D chiral designs show an interesting coupled compression-twisting behavior, while the 3D achiral designs show auxetic behavior. Also, besides the cellular-type chiral and achiral designs, composite-type of each design are created by adding soft matrix to the cellular designs. The designs are fabricated via multi-material 3D printing. Mechanical uni-axial compression experiments are performed on the 3D printed specimens and the experimental results are compared with finite element (FE) simulations. By jointly tailoring the chiral geometry and material combination, the effective mechanical properties and the deformation mechanisms can be tuned in a large range. In addition, a continuum-level material model was developed to predict the constitutive relationship. The results show that the material model can well predict the effective mechanical properties of the chiral 3D mechanical metamaterials.
通过球面平铺法设计手性和非手性机械超材料。三维手性设计表现出有趣的压缩-扭转耦合行为,而三维非手性设计则表现出形变行为。此外,除了细胞型手性和非手性设计外,每种设计的复合类型都是通过在细胞设计中添加软矩阵来创建的。这些设计是通过多材料3D打印制造的。对3D打印试件进行了单轴压缩力学实验,并与有限元模拟结果进行了比较。通过手性几何和材料组合的共同裁剪,可以在较大范围内调整有效的力学性能和变形机理。此外,还建立了一个连续级材料模型来预测本构关系。结果表明,该材料模型能较好地预测手性三维机械超材料的有效力学性能。
Highly water-dispersible methylpyridinium salt functionalized reduced graphene oxide and poly(vinyl alcohol) composites
Sangyoon Lee, Jeong-Un Jin, Jae Ryang Hahn, Seongwoo Ryu, Nam-Ho You
doi:10.1016/j.compositesb.2023.111142
高水分散性甲基吡啶盐功能化还原氧化石墨烯和聚乙烯醇复合材料
The main issues with developing graphene as a reinforcement are its mono-dispersive properties and strong interfacial bonding between matrix and graphene. In this study, we synthesized reduced graphene oxide (rGO) that is mono-dispersive in polar solvents, by designing structural isomers (-para and -meta) for poly(vinyl alcohol) (PVA) nanocomposites. The hydrazine-methylpyridine synthesized with different structural isomers was used to reduce and functionalize graphene oxide (GO). The -meta structural isomers showed a higher reduction rate and functional groups on GO than -para due to the difference in electrophilic strain. In particular, the prepared rGO reduced by meta-hydrazine-methylpyridine (m-Py-rGO) exhibited excellent mono dispersive characteristics in water solvents as well as in PVA matrix. As a result, nanocomposites containing 1 wt % m-Py-rGO increased in tensile strength and modulus by 48 % (85.95 MPa) and 82 % (4.27 GPa), respectively, compared to pristine PVA. In this study, a method for manufacturing rGO with excellent dispersibility in water, an inexpensive solvent, and its application method are presented.
开发石墨烯作为增强材料的主要问题是其单分散性和基体与石墨烯之间的强界面键合。在这项研究中,我们通过设计聚乙烯醇(PVA)纳米复合材料的结构异构体(-对异构体和-元异构体),合成了在极性溶剂中单分散的还原性氧化石墨烯(rGO)。用不同结构异构体合成的肼-甲基吡啶对氧化石墨烯进行了还原和功能化。由于亲电应变的差异,-元结构异构体在氧化石墨烯上的还原率和官能团均高于-对结构异构体。其中,间肼-甲基吡啶还原制备的还原氧化石墨烯(m-Py-rGO)在水溶剂和PVA基质中均表现出优异的单分散性。结果表明,与原始PVA相比,含有1 wt % m-Py-rGO的纳米复合材料的抗拉强度和模量分别提高了48 % (85.95 MPa)和82 % (4.27 GPa)。本研究提出了一种制备在水(一种廉价的溶剂)中具有优异分散性的氧化石墨烯的方法及其应用方法。
Use of a commingling process for innovative flax fibre reinforced unidirectional composites
Elouan Guillou, Mahadev Bar, Mario Scheel, Thierry Falher, Timm Weitkamp, Darshil U. Shah, Alexandre Beigbeder, Pierre Ouagne, Alain Bourmaud
doi:10.1016/j.compositesb.2023.111150
使用混合工艺的创新亚麻纤维增强单向复合材料
Optimisation of textile preforms play a crucial role in the development of high-performance biobased composites materials. In this context, the main ambition of this work is to quantify and assess the mechanical properties and behaviour of biocomposite materials made from unidirectional commingled preforms based on flax and poly-(propylene) fibres. To the best of our knowledge, there is no literature examining the effect of the commingling process on the ultrastructure and the mechanical properties of flax fibres. At the scale of the elementary fibre, fibre mechanical properties are observed to be stable after commingling. However, repeated drawing in the commingling process leads to increased cellulose crystallinity and a larger fraction of elementary fibres exhibiting quasi-linear tensile behaviour. The composite materials produced with these commingled flax/poly-(propylene) preforms contain few cortical residues and show a remarkable degree of fibre individualisation. Moreover, they exhibit high Young's modulus and a stress at break of 24 GPa and 194 MPa, respectively, for a fibre volume fraction of 36 %. A substantial drop in properties is however noted at high fibre fractions due increased heterogeneity of the materials. Remarkably, the biocomposites achieved unprecedented transverse modulus and stress at break of 2.3 GPa and 16.5 MPa, respectively. Our results validate the potential and interest in commingling processes for designing a new family of plant fibre composite materials.
纺织预成型的优化在高性能生物基复合材料的发展中起着至关重要的作用。在这种情况下,这项工作的主要目标是量化和评估由基于亚麻和聚丙烯纤维的单向混合预制体制成的生物复合材料的机械性能和行为。据我们所知,目前还没有文献研究混炼过程对亚麻纤维超微结构和力学性能的影响。在初等纤维的尺度上,共混后纤维的力学性能稳定。然而,在混炼过程中反复拉伸会导致纤维素结晶度的增加和更大比例的初等纤维表现出准线性拉伸行为。用这些混合亚麻/聚丙烯预制体生产的复合材料含有很少的皮质残留物,并显示出显著的纤维个性化程度。此外,当纤维体积分数为36% %时,它们具有较高的杨氏模量和断裂应力,分别为24 GPa和194 MPa。然而,由于材料的不均匀性增加,在高纤维馏分时,性能显著下降。值得注意的是,生物复合材料的横向模量和断裂应力分别达到了前所未有的2.3 GPa和16.5 MPa。我们的研究结果验证了设计一种新型植物纤维复合材料的混炼工艺的潜力和兴趣。