今日更新：Composite Structures 1 篇，Composites Part B: Engineering 4 篇Composite StructuresNumerical investigation of the bearing performance of Thin- and Thick-Ply hybrid laminatesBenedikt Kötter, Kohei Yamada, Naoki Takatsuka, Bodo Fiedler, Masaaki Nishikawadoi:10.1016/j.compstruct.2024.118372薄层和厚层混合层压板轴承性能的数值研究This publication presents a numerical investigation of Thin-Ply Hybrid CFRP bolted joints. In addition to Thin- and Thick-Ply specimens, hybrid specimens are investigated by substituting a part of the 90° CFRP layers with stainless steel foils. The numerical investigations are based on preliminary experimental work, which showed that fibre kinking led to final failure. A modelling strategy that includes 3D stress states and fibre kinking is chosen. The influence of micro-damages such as matrix cracks decreases with decreasing layer thickness. Therefore, and to avoid high computational power, primarily micro-damages such as matrix cracks are not included. The results of the simulations of the Thin-Ply and the hybrid samples show a good agreement with the experimental results. By hybridisation, the bearing performance can be significantly increased. It is shown that the modelling approach of not including micro-damage is well applicable for thinner plies but reaches its limits for thicker plies.本出版物介绍了薄层混合 CFRP 螺栓连接的数值研究。除了薄层和厚层试样外，还研究了用不锈钢箔替代部分 90° CFRP 层的混合试样。数值研究以初步实验为基础，实验表明纤维扭结会导致最终失效。选择的建模策略包括三维应力状态和纤维扭结。基体裂缝等微损伤的影响随着层厚度的减小而减弱。因此，为了避免高计算能力，主要不包括基体裂缝等微损伤。薄层样本和混合样本的模拟结果与实验结果非常吻合。通过混合，轴承的性能可以显著提高。结果表明，不包括微损伤的建模方法非常适用于较薄的层，但对于较厚的层则达到了极限。Composites Part B: EngineeringStress engineering of SiCf/SiC composites: interfacial stress adjustment and its effects on tensile behaviors of UD SiCf/SiC composites fabricated by hybrid CVI and PIP methodsYucong Wei, Fang Ye, Laifei Cheng, Guangda Guodoi:10.1016/j.compositesb.2024.111711碳化硅/碳化硅复合材料的应力工程学：界面应力调整及其对采用混合 CVI 和 PIP 方法制造的 UD 碳化硅/碳化硅复合材料拉伸行为的影响Internal stress is usually generated during the preparation of the SiCf/SiC composites and is generally considered to be uncontrollable and detrimental to SiCf/SiC composite’s mechanical properties. However, in this study, internal stress is proposed for the first time as a tool to regulate the interfacial bonding properties of the SiCf/SiC composites. And the interfacial compressive stress was successfully controlled by hybrid CVI and PIP methods. The results of Raman analysis show that the interfacial compressive stress increases with the increase of the PIP SiC content. The interfacial shear strength (τi) and interfacial dynamic friction strength (τf) was determined by micro-shear tests. Both τi and τf increase with the increase of interfacial compressive stress. With different interfacial bonding strength, the SiCf/SiC composites show different tensile behaviors. A high τi can lead to a high tensile modulus and proportional limit stress (PLS) and a high τf can lead to the disappearance of the second linear stage and low fracture strain. The axial residual stress of matrix also was tested, and the results indicate that it does not have a dominant influence on the mechanical properties. Finally, the SiCf/SiC composites achieve the superhigh PLS of 729.8±9.2 MPa and modulus of 288.0±7.9 GPa when the BN thickness is 100nm and the interfacial compressive stress is 1127.7 MPa. This strategy of interfacial stress engineering may provide a new and valuable design idea for improving the mechanical properties of the SiCf/SiC composite and other composites. This strategy is also of great significance for broadening the design criteria and enriching the preparation methods and internal stress regulation methods of high-performance composites.内应力通常是在制备碳化硅/碳化硅复合材料的过程中产生的，通常被认为是不可控的，并且不利于碳化硅/碳化硅复合材料的机械性能。然而，本研究首次提出将内应力作为调节 SiCf/SiC 复合材料界面结合性能的工具。通过混合 CVI 和 PIP 方法成功地控制了界面压应力。拉曼分析结果表明，界面压应力随 PIP SiC 含量的增加而增大。界面剪切强度（τi）和界面动摩擦强度（τf）是通过微剪切试验测定的。τi和τf都随着界面压应力的增加而增加。在不同的界面结合强度下，SiCf/SiC 复合材料表现出不同的拉伸行为。高τi可导致高拉伸模量和比例极限应力（PLS），高τf可导致第二线性阶段消失和低断裂应变。此外，还测试了基体的轴向残余应力，结果表明它对机械性能的影响不大。最后，当 BN 厚度为 100nm 且界面压应力为 1127.7 MPa 时，SiCf/SiC 复合材料达到了 729.8±9.2 MPa 的超高 PLS 和 288.0±7.9 GPa 的模量。这种界面应力工程学策略可为改善 SiCf/SiC 复合材料及其他复合材料的机械性能提供一种新的、有价值的设计思路。这一策略对于拓宽高性能复合材料的设计标准、丰富制备方法和内应力调节方法也具有重要意义。Compressive failure mechanisms in unidirectional fiber reinforced polymer composites with embedded wrinklesShashidhar Krishnappa, Suhasini Gururajadoi:10.1016/j.compositesb.2024.111688嵌入皱纹的单向纤维增强聚合物复合材料的压缩破坏机制The present study examines how wrinkles affect a composite material’s compressive failure behavior. Uni-directional carbon fiber-reinforced plastics (UD-CFRP) with artificially induced wrinkles were fabricated by placing laminate strips in specific positions. The geometry and placement of these strips were varied, resulting in 18 different wrinkle configurations. Through extensive experimental testing, it was observed that the compressive strength decreased significantly, ranging from 20% to 73%, depending on the specific wrinkle configuration. The experimental results were found to align well with existinganalytical models. Additionally, the study examined how the wrinkle characteristics affected the final kink bandwidth, angle, and inclination. Fractographic studies on the failed specimens revealed various damage modes at different length scales, including kinking, delamination, buckle delamination, crushing, fiber pullout, matrix cracking/failure, and fiber failure. Based on these findings, it is emphasized that the geometry of the wrinkles and the aforementioned damage modes at different length scales must be accounted for while developing a numerical model to predict the compressive behavior of the composite accurately.本研究探讨了皱纹如何影响复合材料的压缩破坏行为。通过在特定位置放置层压条，制作了具有人工诱导皱纹的单向碳纤维增强塑料（UD-CFRP）。这些条带的几何形状和位置各不相同，从而产生了 18 种不同的皱纹配置。通过大量的实验测试，观察到抗压强度明显下降，根据具体的皱纹配置，下降幅度在 20% 到 73% 之间。实验结果与现有的分析模型十分吻合。此外，研究还考察了皱纹特征如何影响最终的扭结带宽、角度和倾斜度。对失效试样进行的断裂研究揭示了不同长度尺度上的各种损坏模式，包括扭结、分层、扣压分层、挤压、纤维拉出、基质开裂/失效和纤维失效。基于这些发现，我们强调在开发数值模型以准确预测复合材料的抗压行为时，必须考虑到皱纹的几何形状和上述不同长度尺度的损伤模式。Energetic aqueous zinc-sulfur battery achieved via co-solvent and redox mediator synergistic regulationBoao Wanyan, Yaoyuan Zhan, Zhonghao Miao, Wenbo Guo, Jiehua Wang, Lei Yan, Liyuan Zhang, Haoxiang Yu, Ting-Feng Yi, Jie Shudoi:10.1016/j.compositesb.2024.111709 通过共溶剂和氧化还原介质协同调节实现高能锌硫水溶液电池Aqueous Zn–S batteries (AZSBs) have received significant attention due to the outstanding energy density, low cost, and high safety. However, the slow kinetics and poor reversibility of the sulfur conversion reaction, coupled with the formation of dendrites in zinc anode and hydrogen evolution reaction (HER), hinder the practical applications of AZSBs. In this paper, we developed a novel co-solvent electrolyte that utilizes N-methylpyridine (NMP) and KI as additives to regulate the cathode reversibility and anode stability synergistically. Firstly, the electrophilic group of NMP (–CO–NR2-) effectively activates the oxidation of I− to form I3−. The resulting I3−/I− redox mediator participates in the sulfur conversion reaction and lowers its energy barrier, thus enhancing the reaction kinetics of ZnS ↔ S and inhibiting the formation of irreversible by-products. Secondly, NMP alters the solvation structure of Zn(H2O)62+, achieving uniform deposition of Zn2+ and inhibiting the growth of zinc dendrites. Thirdly, NMP forms a dense solid-electrolyte-interphase layer between the zinc metal and H2O during cycling, inhibiting HER. Under the synergistic effect from solvent and redox mediator, AZSBs exhibit an impressive capacity of 775 mAh g−1 at 5 A g−1 (10 C) with 77.5 % capacity retention after 300 cycles.锌-硫水溶液电池（AZSB）因其出色的能量密度、低成本和高安全性而备受关注。然而，硫转化反应的动力学慢、可逆性差，再加上锌阳极树枝状物的形成和氢进化反应（HER），阻碍了 AZSB 的实际应用。本文开发了一种新型共溶剂电解质，利用 N-甲基吡啶（NMP）和 KI 作为添加剂，协同调节阴极的可逆性和阳极的稳定性。首先，NMP 的亲电基团（-CO-NR2-）能有效激活 I- 的氧化反应，生成 I3-。由此产生的 I3-/I- 氧化还原介质参与硫转化反应并降低其能障，从而提高 ZnS ↔ S 的反应动力学并抑制不可逆副产物的形成。其次，NMP 可改变 Zn(H2O)62+ 的溶解结构，实现 Zn2+ 的均匀沉积，抑制锌枝晶的生长。第三，在循环过程中，NMP 会在锌金属和 H2O 之间形成致密的固态电解质相间层，从而抑制 HER。在溶剂和氧化还原介质的协同作用下，AZSBs 在 5 A g-1 (10 C) 的条件下显示出惊人的 775 mAh g-1 容量，循环 300 次后容量保持率达 77.5%。Enhanced Photocatalytic Reduction of p-Nitrophenol by Polyvinylpyrrolidone-Modified MOF/Porous MgO Composite HeterostructuresAnanda Repycha Safira, Abdullah H. Alluhayb, Mohammad Aadil, Mohammad Alkaseem, Arash Fattah-alhosseini, Mosab Kaseemdoi:10.1016/j.compositesb.2024.111710聚乙烯吡咯烷酮修饰的 MOF/多孔氧化镁复合异质结构增强了对硝基苯酚的光催化还原作用Catalysts derived from Metal-Organic Frameworks (MOF) present a compelling blend of cost-effectiveness and superior performance in reduction reactions. In this study, polymer-decorated MOF-Cobalt (MOF-Co) was deposited onto porous magnesium oxide (MgO) layers, acquired through surface modification of AZ31 Mg alloy via plasma-assisted oxidation, with the aim of fabricating novel catalysts for reduction reactions. Herein, this synthesis involved the utilization of Cobalt- benzene dicarboxylic acid (Co-BDC), where cobalt ions served as metal nodes and 1,4-benzene dicarboxylic acid (H2BDC) functioned as an organic linker, with and without the presence of polyvinylpyrrolidone (PVP) as an active site enhancer. The morphology of the prepared catalysts was affected by several factors such as pH, hydrothermal treatment duration, PVP content, and the presence of a MgO layer. The optimal catalyst, designated as metal-organic frameworks-cobalt at 80°C temperature and 1 hour of hydrothermal treatment at pH 4 (MOF-Co 1.4), was synthesized on the MgO layer using a solution containing 1.7 g of PVP, H2BDC, and Co(NO₃)₂.6H₂O. The paper-like morphology of the MOF-Co 1.4 catalyst facilitated exceptional performance, efficiently degrading p-nitrophenol (p-NP) under visible light irradiation with an impressive 99.74% efficiency within just 5 minutes of exposure, while also demonstrating stability over five successive cycles. ·O2- species was found to drive the reduction reaction to p-aminophenol, with harmless compounds as byproducts, while GC-MS analysis identified intermediates in the reduction of p-NP. Density functional theory (DFT) calculations suggested that H2BDC and PVP jointly provided multi-active sites, enabling effective contact with reactants and rapid electron transfer, thus playing a synergistic role in the catalytic reduction process. This study pioneers a novel method for designing efficient bulk catalysts, achieving high efficiency and stability in pollutant degradation with fast, low-energy fabrication.在还原反应中，金属有机框架（MOF）催化剂兼具成本效益和卓越性能。本研究将聚合物装饰的 MOF-钴（MOF-Co）沉积到多孔氧化镁（MgO）层上，这种多孔氧化镁是通过等离子体辅助氧化法对 AZ31 镁合金进行表面改性而获得的，目的是制造新型还原反应催化剂。在这种合成中，钴-苯二羧酸（Co-BDC）被用作金属节点，1,4-苯二羧酸（H2BDC）被用作有机连接剂，聚乙烯吡咯烷酮（PVP）被用作活性位点增强剂。所制备催化剂的形态受多种因素的影响，如 pH 值、水热处理持续时间、PVP 含量以及是否存在氧化镁层。使用含有 1.7 克 PVP、H2BDC 和 Co(NO₃)₂.6H₂O 的溶液在 MgO 层上合成了最佳催化剂，即金属有机框架-钴，温度为 80°C，pH 值为 4，水热处理时间为 1 小时（MOF-Co 1.4）。MOF-Co 1.4 催化剂的纸张状形态有助于提高其卓越的性能，在可见光照射下，对硝基苯酚（p-NP）的降解效率在短短 5 分钟内就达到了令人印象深刻的 99.74%，同时在五个连续循环中也表现出了稳定性。-研究发现，-O2-物种驱动了对氨基苯酚的还原反应，副产物为无害化合物，而 GC-MS 分析则确定了对-NP 还原过程中的中间产物。密度泛函理论（DFT）计算表明，H2BDC 和 PVP 共同提供了多活性位点，使其能够与反应物有效接触并快速进行电子转移，从而在催化还原过程中发挥了协同作用。这项研究开创了设计高效块状催化剂的新方法，通过快速、低能耗的制造实现了高效、稳定的污染物降解。来源：复合材料力学仿真Composites FEM
