今日更新:Composite Structures 1 篇,Composites Part B: Engineering 4 篇
Composite Structures
Numerical investigation of the bearing performance of Thin- and Thick-Ply hybrid laminates
Benedikt Kötter, Kohei Yamada, Naoki Takatsuka, Bodo Fiedler, Masaaki Nishikawa
doi: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.
Stress 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 methods
Yucong Wei, Fang Ye, Laifei Cheng, Guangda Guo
doi: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.
Compressive failure mechanisms in unidirectional fiber reinforced polymer composites with embedded wrinkles
Shashidhar Krishnappa, Suhasini Gururaja
doi: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.
Energetic aqueous zinc-sulfur battery achieved via co-solvent and redox mediator synergistic regulation
Boao Wanyan, Yaoyuan Zhan, Zhonghao Miao, Wenbo Guo, Jiehua Wang, Lei Yan, Liyuan Zhang, Haoxiang Yu, Ting-Feng Yi, Jie Shu
doi: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 Heterostructures
Ananda Repycha Safira, Abdullah H. Alluhayb, Mohammad Aadil, Mohammad Alkaseem, Arash Fattah-alhosseini, Mosab Kaseem
doi: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.