【新文速递】2024年8月2日固体力学SCI期刊最新文章

今日更新：Composite Structures 3 篇，Composites Part B: Engineering 9 篇，Composites Science and Technology 1 篇Composite StructuresEffect of composite lattice on the high-temperature compressive behavior of silicone rubber based ablative materialsPeixin Yang, Wu Yuan, Hongwei Songdoi:10.1016/j.compstruct.2024.118337复合晶格对硅橡胶基烧蚀材料高温压缩行为的影响Besides aerodynamic heating, ablative materials are always exposed to aerodynamic pressure. This paper proposes an effective method to improve the high-temperature compressive performance of silicone rubber based ablative materials using silica/phenolic pyramidal lattice. Composite structures of silica/phenolic pyramidal lattice reinforced silicone rubber based ablative material were fabricated and tested with the high-temperature material testing machine. To determine the stiffness of lattice reinforced ablative materials at different temperatures, a theoretical model was developed and validated by comparison with experimental results. Results show that silica/phenolic pyramidal lattices can significantly improve the stiffness of ablative materials at high temperatures. The changes in the stiffness of ablative materials reinforced with silica/phenolic pyramidal lattices at high temperatures can be divided into four stages. The composite lattice has a reinforcing effect on the mechanical properties of ablative materials up to 1000 °C, with optimal enhancement observed at 681 °C. Furthermore, the effects of geometrical parameters of the lattice and heating rates on stiffness at high temperatures are also discussed.除了空气动力加热外，烧蚀材料还始终暴露在空气动力压力下。本文提出了一种利用二氧化硅/酚醛金字塔晶格改善硅橡胶基烧蚀材料高温抗压性能的有效方法。本文制作了二氧化硅/酚醛金字塔晶格增强硅橡胶基烧蚀材料的复合结构，并用高温材料试验机进行了测试。为了确定晶格增强烧蚀材料在不同温度下的刚度，建立了一个理论模型，并通过与实验结果的比较进行了验证。结果表明，二氧化硅/酚醛金字塔晶格能显著提高烧蚀材料在高温下的刚度。使用二氧化硅/酚醛金字塔晶格增强的烧蚀材料在高温下的刚度变化可分为四个阶段。复合晶格对烧蚀材料的机械性能有增强作用，最高可达 1000 ℃，在 681 ℃ 时达到最佳增强效果。此外，还讨论了晶格几何参数和加热速率对高温刚度的影响。Influence of new AA 2xxx layers on the strength and damage responses of fibre metal laminates during soft body impactS. Kavitha Mol, A. Sadiqdoi:10.1016/j.compstruct.2024.118339新型 AA 2xxx 层对纤维金属层压板在软体冲击过程中的强度和损伤响应的影响This study focuses on analysing the effect of new AA 2xxx layers on the strength and damage response of Fibre Metal Laminates (FMLs) during bird strikes. New aluminium alloy (new AA 2xxx) designed for the leading edge of aircraft to withstand bird strikes. Four laminates of different metal thicknesses and stacking sequences were modelled with this new 2xxx aluminium alloy. These laminates were analysed based on the impact responses (reaction force, deflection, and energy dissipation) and damage behaviours (metal failure, matrix failure, fibre failure, and delamination) during a soft body (bird) impact. A comparative study found that four FMLs exhibited different impact behaviours in terms of metal thickness and layup sequence. The FML configuration (FML 5–2/1–0.2) arranges glass/epoxy layers between thinner layers of new aluminium alloy and is best suited for designing the leading edges of wing and tail structures. The new FML increases ultimate bird impact strength by 23.65% compared to conventional GLARE™ laminates.本研究的重点是分析新 AA 2xxx 层对鸟击时金属纤维层压板 (FML) 的强度和损坏响应的影响。为飞机前缘设计的新型铝合金（新型 AA 2xxx）可抵御鸟击。使用这种新型 2xxx 铝合金对四种不同金属厚度和堆叠顺序的层压板进行了建模。根据软体（鸟类）撞击时的撞击响应（反作用力、挠度和能量耗散）和损坏行为（金属破坏、基体破坏、纤维破坏和分层）对这些层压板进行了分析。比较研究发现，四种 FML 在金属厚度和铺层顺序方面表现出不同的冲击行为。FML 配置（FML 5-2/1-0.2）在较薄的新型铝合金层之间安排了玻璃/环氧层，最适合设计机翼和尾翼结构的前缘。与传统的 GLARE™ 层压板相比，新型 FML 可将鸟撞击极限强度提高 23.65%。A comparative study on the mechanical properties of sandwich beams made with PET FRP facings and varied recycled PET coresRaghad Kassab, Pedram Sadeghiandoi:10.1016/j.compstruct.2024.118340使用 PET FRP 面板和各种回收 PET 内芯制作的夹层梁机械性能比较研究The objective of this paper is to assess the mechanical performance of new forms of sandwich beams predominantly comprised of recycled plastic polymers. These beams feature two types of polyethylene terephthalate (PET) fiber-reinforced polymer (FRP) facings: one with a bio-resin matrix and the other with a partial bio-resin matrix. The core of the beams is a focal point of the study as well, comprised of recycled PET (R-PET). Fifteen different types of sandwich beams were tested, with three identical specimens from each type, totaling 45 beams. Each beam, measuring 240 mm in length, was fabricated and categorized based on its core composition: either an R-PET honeycomb or an R-PET foam core. The study investigated key parameters including the core type (honeycomb or foam), core thickness (12 mm or 15 mm), core orientation, and facing thicknesses (1 mm or 2 mm). The mechanical testing of these beams involved a four-point bending setup to assess their flexural performance. This included analyzing mid-span load–deflection, moment–curvature behaviours, and changes in tension and compression strains in the facings during bending. The results demonstrated that core density, type, and facing thickness significantly impact the beams’ stability and failure modes. High-density foam cores primarily failed through core shear, while lower density cores showed both core shear and wrinkling, dependent on facing thickness and core type, highlighting the complex influence of material properties on structural behaviour. A finite element (FE) model was developed to verify the experimental findings, effectively corroborating the test results. The research data is intended as a reference for structural designers seeking to incorporate sustainable alternatives into traditional building materials, thereby promoting a more environmentally conscious approach within the construction industry.本文旨在评估主要由回收塑料聚合物组成的新型夹层梁的机械性能。这些横梁具有两种类型的聚对苯二甲酸乙二醇酯（PET）纤维增强聚合物（FRP）面层：一种是生物树脂基质，另一种是部分生物树脂基质。横梁的核心部分也是研究的重点，由再生 PET（R-PET）组成。共测试了 15 种不同类型的夹层梁，每种类型有三个相同的试样，共计 45 根梁。每根横梁的长度为 240 毫米，根据其核心成分进行制造和分类：R-PET 蜂窝或 R-PET 泡沫核心。研究调查了关键参数，包括芯材类型（蜂窝或泡沫）、芯材厚度（12 毫米或 15 毫米）、芯材方向和面材厚度（1 毫米或 2 毫米）。这些梁的机械测试包括四点弯曲设置，以评估其抗弯性能。这包括分析跨中荷载-挠度、力矩-曲率行为，以及弯曲过程中面层的拉伸和压缩应变变化。结果表明，芯材密度、类型和面层厚度对横梁的稳定性和失效模式有重大影响。高密度泡沫芯材主要通过芯材剪切失效，而低密度芯材则同时表现出芯材剪切和起皱，这取决于面层厚度和芯材类型，突出了材料特性对结构行为的复杂影响。开发的有限元（FE）模型验证了实验结果，有效地证实了测试结果。研究数据旨在为结构设计师提供参考，帮助他们在传统建筑材料中加入可持续替代材料，从而在建筑行业中推广更具环保意识的方法。Composites Part B: EngineeringEngineered mechanical dynamics in biomimetic hydrogel scaffold promotes phenotypic maintenance and cartilage formation of chondrocytesYinghua Gao, Xuran Guo, Xiaoli Wang, Donghong Li, Han Tang, Weisong Zhao, Tingting Xu, Sha-sha Wang, Fen Li, Hao Zhang, Bei Feng, Yanzhong Zhangdoi:10.1016/j.compositesb.2024.111665 在仿生水凝胶支架中设计机械动力学，促进软骨细胞的表型维持和软骨形成The dedifferentiation of chondrocytes in cartilage tissue engineering (CTE) remains an unsolved challenge for the successful repair of severe articular cartilage defects. We proposed to construct a mechanoactive CTE scaffold, featured with an engineered capability of in situ exerting reversible mechanical stimuli by itself upon having its environment temperature varied, to address this noted issue. For this purpose, poly(N-isopropylacrylamide) (PNIPAM) grafting and methacrylic anhydride (MA) grafting were firstly performed to modify chitosan to generate a thermo-responsive and photo-crosslinkable hydrogel (PCM), and then fragmented electrospun poly(L-lactide-co-caprolactone) (PLCL) fibers were used as fillers to reinforce the PCM hydrogel and to achieve a structural resemblance to the extracellular matrix (ECM) of cartilage. This newly-engineered composite hydrogel, due to the presence of the thermo-responsive component of PNIPAM, allowed to dynamically regulate the chondrocytic behavior when intermittently switching the environmental temperature between 26 °C and 37 °C. It was found the dynamic mechanical stimulus applied by the mechanoactive hydrogel had no adverse effect on the chondrocytes’ viability and proliferation. Intriguingly, in the absence of any chondrogenic supplements, chondrocytes, subjected to the dynamic mechanical stimulation exerted by the composite hydrogel for 7 days in vitro, displayed a native-like cytomorphology, and expressed abundant chondrogenic markers, evidently showing the desired phenotypic maintenance outcomes. By having the chondrocytes encapsulated in the mechanoactive hydrogel and implanted through a rat subcutaneous heterotopic model, we further demonstrated that in situ applied mechanical stimuli by the scaffold per se also effectively promoted the formation of cartilage tissue in vivo. This demonstrated strategy of enabling biomimetic scaffold to be mechanoactive could open a new dimension in the design of functional scaffolds for regulation of cellular functions, essential in fulfilling the dream of functional tissue engineering for cartilage regeneration.软骨组织工程（CTE）中软骨细胞的去分化仍是成功修复严重关节软骨缺损的一个未解难题。为了解决这一问题，我们提出了一种机械活性 CTE 支架，其特点是在改变环境温度时，能在原位自行施加可逆的机械刺 激。为此，首先对壳聚糖进行聚（N-异丙基丙烯酰胺）（PNIPAM）接枝和甲基丙烯酸酐（MA）接枝改性，生成热响应和光交联水凝胶（PCM）、然后用破碎的电纺聚（L-内酰胺-共己内酯）（PLCL）纤维作为填充物来加固 PCM 水凝胶，使其结构类似于软骨的细胞外基质（ECM）。这种新设计的复合水凝胶由于含有 PNIPAM 的热响应成分，当环境温度在 26 °C 和 37 °C 之间间歇切换时，可以动态调节软骨细胞的行为。研究发现，机械活性水凝胶施加的动态机械刺 激对软骨细胞的活力和增殖没有不良影响。耐人寻味的是，在没有任何软骨生成补充剂的情况下，软骨细胞在体外接受复合水凝胶施加的动态机械刺 激 7 天后，显示出类似于原生细胞的形态，并表达出丰富的软骨生成标记物，显然显示出所需的表型维持结果。通过将软骨细胞包裹在机械活性水凝胶中并植入大鼠皮下异位模型，我们进一步证明，支架本身在原位施加的机械刺 激也能有效促进软骨组织在体内的形成。这种使生物仿生支架具有机械活性的策略可为调节细胞功能的功能性支架设计开辟一个新的领域，对实现软骨再生的功能性组织工程梦想至关重要。Tailoring microenvironment responsive Fe/Cu micro-galvanic couples on polyetheretherketone for selective antibacteria and osteogenesisZhiyu Hou, Ji Tan, Shiwei Guan, Chao Wei, Zhenhao Hou, Xianming Zhang, Xuanyong Liudoi:10.1016/j.compositesb.2024.111670在聚醚醚酮上定制微环境响应型铁/铜微电偶，用于选择性抗菌和骨生成Polyetheretherketone (PEEK) has become an ideal bone implant material owing to its good mechanical properties and X-ray permeability, but bacterial infection and aseptic loosening often lead to implant failure. Therefore, it is urgent to enhance its osteogenic and antibacterial capabilities, but how to selectively kill bacteria and improve osteogenesis remains an intractable challenge. Here, we designed a microenvironment-responsive Fe/Cu micro-galvanic couple modified layer, which was in situ fabricated on PEEK via plasma techniques. The electron transfer effect of Fe/Cu micro-galvanic couples induced the production of hydroxyl radical and superoxide anion, and this process could be enhanced in the acid bacterial infection microenvironment. Thus, the as-prepared modified PEEK showed good broad-spectrum antibacterial properties with bactericidal efficiency of 99.9% against both S. aureus and E. coli in vitro, and 98.6% against S. aureus in vivo. More importantly, in the normal physiological environment, the Fe/Cu nano heterostructure modified layer could promote the adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells. This innovative strategy gives a new slight for endowing PEEK implants with selective antibacterial and osteogenic abilities, which has great potential in the clinic.聚醚醚酮（PEEK）具有良好的机械性能和 X 射线渗透性，已成为理想的骨植入材料，但细菌感染和无菌松动往往导致植入失败。因此，提高其成骨和抗菌能力迫在眉睫，但如何选择性地杀死细菌并改善成骨效果仍是一个棘手的难题。在此，我们设计了一种微环境响应的铁/铜微电偶修饰层，并通过等离子体技术在 PEEK 上进行了原位制备。铁/铜微电偶的电子传递效应诱导产生羟基自由基和超氧阴离子，而这一过程在酸性细菌感染的微环境中会增强。因此，所制备的改性聚醚醚酮具有良好的广谱抗菌特性，体外对金黄色葡萄球菌和大肠杆菌的杀菌效率高达 99.9%，体内对金黄色葡萄球菌的杀菌效率高达 98.6%。更重要的是，在正常生理环境下，Fe/Cu 纳米异质结构修饰层可促进骨髓间充质干细胞的粘附、增殖和成骨分化。这一创新策略为赋予 PEEK 植入物选择性抗菌和成骨能力提供了新的思路，在临床上具有巨大潜力。CF/PEEK SKINS ASSEMBLY BY INDUCTION WELDING FOR THERMOPLASTIC COMPOSITE SANDWICH PANELSRomain G. Martin, Christer Johansson, Jason R. Tavares, Martine Dubédoi:10.1016/j.compositesb.2024.111676通过感应焊接组装热塑性复合材料夹芯板的 cf/peek 面板A method to assemble sandwich panels made of carbon fibre reinforced poly-ether-ether-ketone (CF/PEEK) facesheets and 3D-printed poly-ether-imide (PEI) honeycomb cores using induction welding is presented. Induction heating patterns inside CF/PEEK laminates of variable dimensions are first evaluated with a thermal camera and compared to a COMSOL Multiphysics model. Sandwich samples are then prepared by vacuum-assisted continuous induction welding under parameters selected from the modelling effort. Joining of sandwich panels made of CF/PEEK facesheets by induction welding under vacuum is demonstrated. Facesheets do not deconsolidate in the process and core crushing is avoided. Flatwise skin/core strength of the welded samples reaches up to 7 MPa, above reported performance for thermoset or thermoplastic composite sandwich panels.本文介绍了一种利用感应焊接组装由碳纤维增强聚醚醚酮（CF/PEEK）面板和三维打印聚醚酰亚胺（PEI）蜂窝芯制成的夹层板的方法。首先使用热像仪对不同尺寸的 CF/PEEK 层压板内部的感应加热模式进行评估，并与 COMSOL 多物理场模型进行比较。然后，根据建模工作中选定的参数，通过真空辅助连续感应焊接制备夹层样品。演示了在真空条件下通过感应焊接连接 CF/PEEK 面板制成的夹层板。在此过程中，面板不会发生脱固，也避免了夹芯挤压。焊接样品的平向表皮/夹芯强度高达 7 兆帕，高于已报道的热固性或热塑性复合夹层板的性能。Temperature effects on solid state bonding joints of ultrafine-grained CNT/Al-Cu-Mg compositesGuoliang Zuo, Yu Bai, Zhanqiu Tan, Wenxue Fan, Shuyan Shi, Hai Haodoi:10.1016/j.compositesb.2024.111681温度对超细晶粒 CNT/Al-Cu-Mg 复合材料固态粘接接头的影响The joining of CNT/Al composites is a technology bottleneck in its engineering application. In this study, a bonding method of ultrafine-grained CNT/Al-4Cu-1Mg composites was performed. Microstructure and mechanical properties of the joints were characterized, then the interface bonding process and mechanism were explored. The results indicate that increasing temperature can accelerate the healing of interface voids and the dissolution of interface oxides, but overheat will lead to the softening of bonding joints and the conversion of CNTs to Al4C3. Under the optimal temperature of 500 °C, the bonding interface has basically healed, and the bonding strength is up to 380 MPa, which exceeds 90% of the strength of raw materials. Besides, the key to interface healing is the fragmentation and dissolution of interface oxides which have been identified as MgAl2O4. The bonding behavior is a synergistic effect of dynamic recovery, interface migration, and atomic diffusion. Especially, CNTs and Al4C3 phases provide short-circuit diffusion channels and also inhibit the softening of the joints.CNT/Al 复合材料的连接是其工程应用中的一个技术瓶颈。本研究采用超细晶粒 CNT/Al-4Cu-1Mg 复合材料的接合方法。研究表征了接头的微观结构和力学性能，然后探讨了界面粘合过程和机理。结果表明，温度升高可加速界面空隙的愈合和界面氧化物的溶解，但过热会导致接合点软化和 CNT 向 Al4C3 的转化。在 500 °C 的最佳温度下，键合界面已基本愈合，键合强度高达 380 MPa，超过原材料强度的 90%。此外，界面愈合的关键是界面氧化物的破碎和溶解，目前已确定为 MgAl2O4。结合行为是动态恢复、界面迁移和原子扩散的协同效应。特别是，碳纳米管和 Al4C3 相提供了短路扩散通道，也抑制了接合处的软化。Achievement of high-reliability and high-efficient deposit of PA66 by additive friction stir depositionHua Liu, Mengjia Xu, Xiaopeng Lidoi:10.1016/j.compositesb.2024.111682通过添加剂搅拌摩擦沉积实现 PA66 的高可靠性和高效沉积Additive manufacturing (AM) for thermoplastic polymer with the advantages of high specific strength and secondary heating molding has gained wide acceptance in diverse industries. Despite the inherent formation defects associated with AM technologies, a new approach called additive friction stir deposition (AFSD) has emerged. While traditionally utilized for metal deposition, AFSD is now being explored for thermoplastic polymers, specifically polyamide 66 (PA66) in this study. To enhance the reliability and efficiency of AFSD for PA66, the novel gradient-parameter-AFSD (GP-AFSD), bidirectional fast cooling-AFSD (BFC-AFSD) and monodirectional fast cooling-AFSD (MFC-AFSD) based AFSD techniques were introduced. Through the BFC-AFSD and MFC-AFSD, successful PA66 depositions with sound surface and interior formation were achieved. The rapid cooling rates and optimized heat balance in BFC-AFSD and MFC-AFSD processes effectively prevented defects like grooves at the top surface of deposition and achieved reliable control of deposition formation. PA66 samples produced under MFC-AFSD demonstrated a tensile strength of 26.9 MPa and E-modulus of 549.3 MPa at room temperature. These findings highlight the potential of AFSD in fabricating large thermoplastic polymer structures with high reliability and efficiency, thus facilitating the practical application of AFSD technology in engineering.热塑性聚合物的增材制造（AM）具有高比强度和二次加热成型的优点，已被各行各业广泛接受。尽管快速成型技术存在固有的成型缺陷，但一种名为快速摩擦搅拌沉积（AFSD）的新方法已经出现。AFSD 传统上用于金属沉积，现在正被用于热塑性聚合物，特别是本研究中的聚酰胺 66 (PA66)。为了提高 PA66 AFSD 的可靠性和效率，我们引入了基于梯度参数-AFSD（GP-AFSD）、双向快速冷却-AFSD（BFC-AFSD）和单向快速冷却-AFSD（MFC-AFSD）的新型 AFSD 技术。通过 BFC-AFSD 和 MFC-AFSD，成功实现了 PA66 沉积，其表面和内部均形成良好。BFC-AFSD 和 MFC-AFSD 工艺中的快速冷却速率和优化的热平衡有效防止了沉积顶面出现沟槽等缺陷，并实现了对沉积形成的可靠控制。在 MFC-AFSD 工艺下生产的 PA66 样品在室温下的拉伸强度为 26.9 兆帕，E-模量为 549.3 兆帕。这些发现凸显了 AFSD 在高可靠性和高效率制造大型热塑性聚合物结构方面的潜力，从而促进了 AFSD 技术在工程领域的实际应用。Compression behavior of direct compounded compression molded short carbon fiber reinforced thermoplastic pyramidal lattice truss coreRuntian Zhao, Xiang Gu, Ting Wu, Yinhui Li, Xiaodong Zhao, Hui Li, Jianguo Liangdoi:10.1016/j.compositesb.2024.111686直接复合压缩成型的短碳纤维增强热塑性塑料金字塔晶格桁架芯材的压缩性能Lattice truss sandwich structures have a wide range of applications because of its advantages of light weight and high strength. However, current manufacturing processes are not suitable for mass production of lattice truss cores, which limits the promotion of lattice structure. This study utilizes Direct Compounded Compression Molded (DCCM) process to prepare a Short Carbon Fiber Reinforced Thermoplastic (SCFRTP) pyramidal lattice truss core within 5 minutes. The compression behavior and failure mode of the core with joint unconstrained and joint constrained is investigated by experiment, theoretic analysis and finite element method. The results demonstrate that the SCFRTP pyramidal truss core with joint constrained exhibits compressive specific strength (0.0512), surpassing cores of metal and resin significantly. The failure modes of the core with joint unconstrained and the core with joint constrained are joints failure and yield fracture of truss struts respectively. It is believed that the molding process can realize the mass production of lattice truss core structure and promote the wider application of the structure.格构桁架夹层结构具有重量轻、强度高的优点，因此应用广泛。然而，目前的制造工艺并不适合大规模生产格子桁架芯材，这限制了格子结构的推广。本研究采用直接复合压缩成型（DCCM）工艺，在 5 分钟内制备出短碳纤维增强热塑性塑料（SCFRTP）金字塔格状桁架芯材。研究人员通过实验、理论分析和有限元法研究了桁架芯材在连接无约束和连接受约束情况下的压缩行为和失效模式。结果表明，带连接约束的 SCFRTP 金字塔桁架芯材的抗压比强度（0.0512）明显高于金属芯材和树脂芯材。无约束接缝型芯材和有约束接缝型芯材的失效模式分别为接缝失效和桁架支柱屈服断裂。相信该成型工艺可实现格构桁架芯材结构的批量生产，并促进该结构的广泛应用。Lightweight, robust and conductive MXene/SiO2 nanofiber aerogels for excellent sensing and thermal management propertiesYixiang Chen, Tongcheng Zuo, Yu Jiang, Jiajia Gui, Wanqi Feng, Dan Yu, Wei Wangdoi:10.1016/j.compositesb.2024.111669轻质、坚固、导电的 MXene/SiO2 纳米纤维气凝胶具有优异的传感和热管理性能Flexible pressure sensors embody outstanding mechanical and sensing performance, particularly in the fields of personal health monitoring and artificial intelligence, while catering to multifunctional applications resilient against harsh weather conditions. Among these, Ti3C2Tx MXene-based aerogel materials with high surface area and excellent conductivity have attracted a lot of attention. However, there are big challenges in improving the mechanical properties at low densities and designing multi-level pore structures. Herein, the prepared silane monomers (MP) are firstly synthesized by 3-(Trimethoxysilyl) propyl methacrylate (MPTES) and polyethylene glycol diacrylate (PEGDA), then polydopamine-modified silicon dioxide (PDA-SiO2) nanofibers employed with MXene nanosheets form covalent cross-linking nanofiber aerogels. The multi-level stable structure improves both mechanical strength and elasticity. The assembled MXene/MP/PDA-SiO2 pressure sensors exhibit a high sensitivity of −0.83 kPa−1, a rapid response time of 48 ms, a minimum 1 % strain detection limit, and reliable stability over 10,000 cycles. Furthermore, these sensors can be used for human motion detection and health diagnostics, and show good personal thermal management performance. This work holds a promising candidate for the next generation of multifunctional flexible electronic devices.柔性压力传感器具有出色的机械和传感性能，尤其是在个人健康监测和人工智能领域，同时还能满足多功能应用的需求，抵御恶劣的天气条件。其中，具有高比表面积和优异导电性能的 Ti3C2Tx MXene 气凝胶材料备受关注。然而，在提高低密度下的机械性能和设计多层次孔隙结构方面还面临着巨大挑战。本文首先用甲基丙烯酸 3-（三甲氧基硅基）丙酯（MPTES）和聚乙二醇二丙烯酸酯（PEGDA）合成硅烷单体（MP），然后用多巴胺改性二氧化硅（PDA-SiO2）纳米纤维与 MXene 纳米片形成共价交联纳米纤维气凝胶。这种多层次的稳定结构提高了机械强度和弹性。组装后的 MXene/MP/PDA-SiO2 压力传感器具有 -0.83 kPa-1 的高灵敏度、48 毫秒的快速响应时间、最小 1 % 的应变检测极限以及超过 10,000 次循环的可靠稳定性。此外，这些传感器还可用于人体运动检测和健康诊断，并显示出良好的个人热管理性能。这项工作为下一代多功能柔性电子设备提供了一个前景广阔的候选方案。Dispersion Strategy Improves the Mechanical Properties of 3D-Printed Biopolymer NanocompositeDibakar Mondal, Thomas L. Willettdoi:10.1016/j.compositesb.2024.111680分散策略改善了三维打印生物聚合物纳米复合材料的力学性能Homogenous dispersion of nanoparticles in polymer matrices is a technical challenge that if overcome can lead to improved mechanical properties of the resulting nanocomposites. In this work, we successfully refined commercially-available nanoscale, calcium deficient, and poorly crystalline hydroxyapatite (nHA) particles and composited them with acrylate and methacrylate functionalized soybean oil (mAESO) and triethylene glycol dimethacrylate (TEGDMA) producing inks for masked stereolithography (mSLA) -based 3D printing. First, we used shear mixing and ultrasonication on nHA/ethanol mixtures to break down agglomerates and then separated the finest nanoparticles from the remaining agglomerates using centrifugation. The refined nanoparticles (termed fine) were then mixed with the resins and UV-initiator to produce inks for 3D printing. Similarly, we prepared one ink using as-purchased nHA particles (termed raw) and another ink using leftover agglomerates after refinement (termed coarse). We compared the rheological properties of the nHA-resin inks. We used mSLA to fabricate nanocomposite specimens and tested them using flexural, and Mode-I fracture toughness testing following ASTM standards. The dispersion of nanoparticles in the polymer matrix was studied by analyzing backscattered mode scanning electron microscopy images. The nHA particle refinement improved the nanoparticle dispersion in the resin matrix while also increasing the viscosity and shear yield strength of the nanocomposite ink. The flexural fracture strength, flexural modulus, and Mode-I fracture toughness of refined nHA-based nanocomposites were increased by 11%, 71%, and 12%, respectively compared to the raw nHA-based nanocomposites. However, the flexural fracture strain of refined nHA-based nanocomposites was lower by 40% compared to the raw nHA-based nanocomposites. The nanocomposites became stiffer with the incorporation of refined nanoscale nHA. The separation of nanoscale nHA particles, excellent dispersion of these nanoparticles in polymer matrix, and improved flexural strength and modulus opens a new avenue towards the 3D printing of high-performance nHA-based nanocomposites.纳米颗粒在聚合物基质中的均匀分散是一项技术挑战，如果克服了这一挑战，就能提高纳米复合材料的机械性能。在这项工作中，我们成功地提炼出了市售的纳米级、缺钙且结晶度低的羟基磷灰石（nHA）颗粒，并将其与丙烯酸酯和甲基丙烯酸酯功能化大豆油（mAESO）和三乙二醇二甲基丙烯酸酯（TEGDMA）复合，制成了基于掩模立体光刻（mSLA）的三维打印油墨。首先，我们对 nHA/ 乙醇混合物进行剪切混合和超声处理，以分解团聚体，然后使用离心分离法从剩余团聚体中分离出最细小的纳米颗粒。然后将提纯的纳米颗粒（称为细颗粒）与树脂和紫外线引发剂混合，制成用于三维打印的油墨。同样，我们使用购买的 nHA 颗粒（称为生颗粒）制备了一种墨水，并使用精制后剩余的团聚体（称为粗颗粒）制备了另一种墨水。我们比较了 nHA 树脂油墨的流变特性。我们使用 mSLA 制作了纳米复合材料试样，并按照 ASTM 标准对其进行了挠曲和 I 型断裂韧性测试。通过分析背散射模式扫描电子显微镜图像，研究了纳米颗粒在聚合物基体中的分散情况。nHA 粒子细化改善了纳米粒子在树脂基体中的分散性，同时也提高了纳米复合油墨的粘度和剪切屈服强度。与未加工的 nHA 纳米复合材料相比，精制 nHA 纳米复合材料的弯曲断裂强度、弯曲模量和模式 I 断裂韧性分别提高了 11%、71% 和 12%。然而，与未加工的 nHA 基纳米复合材料相比，精制 nHA 基纳米复合材料的弯曲断裂应变降低了 40%。加入精制纳米级 nHA 后，纳米复合材料变得更加坚硬。纳米级 nHA 粒子的分离、这些纳米粒子在聚合物基体中的良好分散以及弯曲强度和模量的提高为高性能 nHA 基纳米复合材料的 3D 打印开辟了一条新途径。Improvement of apparent IFSS and specific modulus of CNT yarnsJefferson Bourdeau, Keenan J. Mintz, Bodiuzzaman Jony, Mohammad Hamza Kirmani, Kishor Gupta, Satish Kumardoi:10.1016/j.compositesb.2024.111683 改善 CNT 纱线的表观 IFSS 和比模量Due to the high strength of carbon nanotubes (CNTs) significant effort has been devoted to incorporating them into fibers and composites. To maximize their potential in these areas, there must be strong interactions between the CNT structures and the matrix of the composite. For CNT yarn, progress in this area has been limited. In this work, we present a method for modifying CNT yarn which improves the apparent interfacial shear strength (IFSS) by up to 45%, as measured by single yarn pullout testing. An ammonium peroxide mixture (APM) treatment method is used to modify the yarn, and this is followed by treatment with commercial sizing agents. A tensioned heat treatment method is also employed to limit the effect of APM treatment on strength and modulus. This method increased the specific modulus of CNT yarns by as much as 16%. The combined heat and chemical treatments yield increases as high as 43% in IFSS and 6% in specific tensile modulus while tempering the decreases in specific tensile strength. The yarn is characterized by SEM, EDS and Raman spectroscopy to show surface carbon being removed from the yarn, seemingly without damaging the CNT structures in the yarn. The main mechanism for IFSS increase appears to be removal of non-graphitic material from the yarn and slight oxidation of the yarn surface. The increase seen in IFSS has the potential to improve the performance of CNT yarn/polymer matrix composites for aerospace applications.由于碳纳米管（CNT）的高强度，人们一直致力于将其融入纤维和复合材料中。要最大限度地发挥碳纳米管在这些领域的潜力，碳纳米管结构与复合材料基体之间必须有很强的相互作用。对于碳纳米管纱线而言，这方面的研究进展有限。在这项工作中，我们提出了一种改性 CNT 纱线的方法，通过单根纱线拉拔测试，该方法可将表观界面剪切强度（IFSS）提高 45%。我们采用过氧化铵混合物 (APM) 处理法对纱线进行改性，然后再用商用上浆剂进行处理。还采用了张力热处理方法，以限制过氧化铵混合物处理对强度和模量的影响。这种方法使 CNT 纱线的比模量提高了 16%。热处理和化学处理相结合的方法使 IFSS 和比拉伸模量分别提高了 43% 和 6%，同时抑制了比拉伸强度的下降。通过扫描电子显微镜（SEM）、电致发光（EDS）和拉曼光谱（Raman spectroscopy）对纱线进行表征，发现纱线表面的碳被去除，但似乎没有破坏纱线中的 CNT 结构。IFSS 增加的主要机制似乎是纱线中的非石墨材料被去除，以及纱线表面轻微氧化。IFSS 的增加有可能提高航空航天应用中 CNT 纱线/聚合物基复合材料的性能。Composites Science and TechnologyEnhanced mechanical strength and stretchable ionic conductive hydrogel with double-network structure for wearable strain sensing and energy harvestingKangkang Ou, Mengting Wang, Chen Meng, Kainan Guo, Nahid Shariar Emon, Jinyi Li, Kun Qi, Yunling Dai, Baoxiu Wangdoi:10.1016/j.compscitech.2024.110732 具有双网络结构的增强机械强度和可拉伸离子导电水凝胶，可用于可穿戴式应变传感和能量收集The conductive hydrogels with skin-like modulus have flourished as a promising soft electronic material for health monitoring and human-machine interface systems. Nevertheless, it is still a challenge to achieve excellent mechanical properties, high ionic conductivity, outstanding structural homogeneity, and biocompatibility of hydrogels through a simple method. Herein, a biocompatible polyacrylamide/calcium alginate/ethanol double-network hydrogel (PAM/CA/EtOH30 DN hydrogel) was prepared via free radical polymerization and solvent-exchange strategy. Benefiting from the synergistic effect of solvent replacement and the dissipating energy of the double-network structure, the resultant PAM/CA/EtOH30 hydrogel showed excellent mechanical properties. In addition, the prepared hydrogels exhibited remarkable stretchability (>1500%), fracture energy (1917 J·m-2), and ionic conductivity (1.53 S·m-1). The PAM/CA/EtOH30-based wearable strain sensor displayed a strain sensing capability with a wide operating range (0%-250%), good sensitivity (GF=1.63), and fast response time. Furthermore, the triboelectric nanogenerator for mechanical energy harvesting was created using the PAM/CA/EtOH30 double-network hydrogel as the electrode, which demonstrated exceptional electrical output performance (up to 236.8V). The proposed PAM/CA/EtOH30 hydrogels with integrated strain sensing and energy harvesting capabilities indicate a valuable potential to be applied to self-powered wearable sensing devices.具有类肤模量的导电水凝胶作为一种前景广阔的软电子材料，在健康监测和人机界面系统中大放异彩。然而，如何通过简单的方法实现水凝胶优异的机械性能、高离子导电性、出色的结构均匀性和生物相容性仍然是一个挑战。本文通过自由基聚合和溶剂交换策略制备了一种生物相容性聚丙烯酰胺/海藻酸钙/乙醇双网络水凝胶（PAM/CA/EtOH30 DN 水凝胶）。得益于溶剂置换和双网络结构耗能的协同作用，制备出的 PAM/CA/EtOH30 水凝胶具有优异的机械性能。此外，所制备的水凝胶还具有显著的拉伸性（>1500%）、断裂能（1917 J-m-2）和离子导电性（1.53 S-m-1）。基于 PAM/CA/EtOH30 的可穿戴应变传感器具有较宽的工作范围（0%-250%）、良好的灵敏度（GF=1.63）和快速的响应时间。此外，以 PAM/CA/EtOH30 双网络水凝胶为电极，创建了用于机械能收集的三电纳米发电机，该发电机具有优异的电输出性能（高达 236.8V）。这种集成了应变传感和能量收集功能的 PAM/CA/EtOH30 水凝胶具有应用于自供电可穿戴传感设备的巨大潜力。来源：复合材料力学仿真Composites FEM