首页/文章/ 详情

【新文速递】2024年11月5日固体力学SCI期刊最新文章

8天前浏览409

 

今日更新:Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 1 篇

Journal of the Mechanics and Physics of Solids

Regularization of softening plasticity with the cumulative plastic strain-rate gradient

G. Bacquaert, J. Bleyer, C. Maurini

doi:10.1016/j.jmps.2024.105923

软化塑性与累积塑性应变率梯度的正则化

We propose a novel variational framework to regularize softening plasticity problems. Specifically, we modify the plastic dissipation potential term by adding a contribution depending on the cumulative plastic strain-rate gradient. We formulate the evolution of the so-obtained strain-rate gradient plasticity model with an incremental variational principle. The time-discretized evolution equations are deduced from the corresponding first-order optimality conditions. To investigate the model, the problem of a bar in traction is studied. Analytical solutions are explicitly derived, and characterized by exponential localization profiles. Contrary to other regularization strategies, no spurious spreading of the plastic localization band is observed. A first numerical implementation in 1D and 2D plane strain conditions is proposed based on conic programming solvers and validated against the analytical predictions. Numerical results on plane strain von Mises plasticity show that the proposed framework leads to mesh-independent results and efficient control of plastic localization bands.

我们提出了一个新的变分框架来正则化软化塑性问题。具体来说,我们通过增加一个依赖于累积塑性应变率梯度的贡献来修改塑性耗散势项。用增量变分原理推导了应变率梯度塑性模型的演化过程。由相应的一阶最优性条件推导出时间离散演化方程。为了验证该模型,研究了牵引杆的问题。解析解被明确地导出,并以指数局域化曲线表征。与其他正则化策略相反,没有观察到塑性局部化带的虚假扩展。提出了基于二次规划求解的一维和二维平面应变条件下的第一个数值实现,并与分析预测进行了验证。平面应变von Mises塑性的数值结果表明,该框架具有网格无关性和塑性局部化带的有效控制。


International Journal of Plasticity

Deformation mechanism of a metastable medium entropy alloy strengthened by the synergy of heterostructure design and cryo-pre-straining

Shilei Liu, Haitao Gao, Daixiu Wei, Charlie Kong, L.S.R. Kumara, M.W. Fu, Hailiang Yu

doi:10.1016/j.ijplas.2024.104162

异质结构设计与低温预应变协同强化亚稳介质熵合金的变形机制

Face-centered cubic (FCC) medium entropy alloys (MEAs) have received considerable attention due to their impressive mechanical properties and responses. However, their practical application is limited by their modest yield strengths. The potential enhancement of the mechanical properties of single-phase MEAs was explored in this study through a synergistic approach combining heterogeneous structure design with subsequent cryo-pre-straining. A heterogeneous lamella structure was produced in a single-phase Fe55Mn20Cr15Ni10 MEA via two-step rolling and annealing. Cryo-pre-straining at varying degrees (6, 12, 21, and 36%) introduced hexagonal close-packed (HCP) phase, high-density dislocations, twins, and stacking faults, leveraging the reduced stacking fault energy at cryogenic temperatures. This process enhanced the alloy's yield strength from 353 MPa to 1.2 GPa (compared to the baseline uniform coarse-grained structure), while maintaining an acceptable total elongation of 8.4%. The impact of cryo-pre-straining on the microstructure and mechanical properties of the MEA was assessed using in-situ synchrotron X-ray diffraction analysis. Cryo-pre-straining (36%) achieved a higher dislocation density (6.1 × 1015 m−2) compared to room-temperature straining (2.5 × 1015 m−2). The stress contribution from HCP-martensite and the evolution of dislocation density during loading were quantified, along with observations of negative stacking fault probability and strain-induced HCP→FCC reverse transformation in cryo-pre-strained samples under loading conditions. Furthermore, the contributions of regulated microstructures to the enhancement of yield strength were quantitatively assessed.

面心立方(FCC)介质熵合金(MEAs)由于其优异的力学性能和响应特性而受到广泛关注。然而,它们的实际应用受到其适度屈服强度的限制。本研究通过非均相结构设计与后续低温预应变相结合的协同方法,探讨了单相MEAs力学性能的潜在增强。通过两步轧制和退火,在单相Fe55Mn20Cr15Ni10 MEA中形成了非均匀片层结构。不同程度的低温预应变(6、12、21和36%)引入了六方密排(HCP)相、高密度位错、孪晶和层错,利用了低温下层错能的降低。该工艺将合金的屈服强度从353 MPa提高到1.2 GPa(与基线均匀粗晶组织相比),同时保持可接受的8.4%的总伸长率。采用原位同步x射线衍射分析方法研究了低温预应变对MEA微观结构和力学性能的影响。与室温拉伸(2.5 × 1015 m−2)相比,低温预拉伸(36%)获得了更高的位错密度(6.1 × 1015 m−2)。定量分析了加载过程中HCP-马氏体的应力贡献和位错密度的演变,并观察了加载条件下低温预应变样品的负层错概率和应变诱导的HCP→FCC反转变。此外,定量评价了调控微观结构对提高屈服强度的贡献。


Thin-Walled Structures

A 3D shell model for static and free vibration analysis of multilayered magneto-elastic structures

S. Brischetto, D. Cesare

doi:10.1016/j.tws.2024.112620

多层磁弹性结构静力和自由振动分析的三维壳模型

In this paper, an exact 3D coupled magneto-elastic shell model for static and free vibration analysis of multilayered piezomagnetic smart structures is presented. The introduction of the mixed curvilinear orthogonal reference system (α,β,z) allows investigations of plates, cylindrical shells, cylinders and spherical shells as actuators or sensors and also in free vibration conditions. The present exact 3D coupled shell model is composed of four second-order differential equations whose primary variables are the three displacements u, v and w and the magnetic potential ψ. Displacements, stresses, strains, magnetic potential, magnetic induction and circular frequency values are computed to understand the behaviour of piezomagnetic smart structures. The resolution method adopted for the present 3D magneto-elastic problem is based on harmonic forms in α and β in-plane directions and the exponential matrix method in the z direction. Simply supported one-layered/multilayered structures with 0° or 90° orthotropic angles have been analyzed. The results section is divided into a first part related to the validation of the proposed 3D model and a second part where new benchmark cases are presented and discussed. Different lamination schemes, load boundary conditions, geometries and materials are studied. Magneto-elastic coupling, thickness and material layer effects are discussed for thin and thick structures. The main novelty of the present exact 3D coupled magneto-elastic shell model stands in the ability to analyze several geometries and multilayered configurations embedding piezomagnetic materials under the action of different boundary loads via a general mathematical formulation.

本文提出了一种用于静态和自由振动分析的多层压电磁智能结构的精确三维耦合磁弹性壳体模型。引入混合曲线正交参考系(α,β,z)允许研究作为致动器或传感器的板、圆柱壳体、圆柱体和球形壳体,以及自由振动条件下的情况。该精确的三维耦合壳体模型由四个二阶微分方程组成,主要变量为三个位移u、v和w以及磁场位势ψ。计算位移、应力、应变、磁场位势、磁场感应和圆频率值以了解压电磁智能结构的行为。该问题的求解方法基于α和β平面方向的谐波形式和z方向的指数矩阵方法。分析了0°或90°各向异性角度的单层/多层结构。结果部分分为两部分,第一部分与所提出的三维模型的验证有关,第二部分则展示了新的基准案例并对其进行了讨论。研究了不同的层压方案、载荷边界条件、几何形状和材料。讨论了薄结构和厚结构中的磁弹性耦合、厚度和材料层效应。当前精确的三维耦合磁弹性壳体模型的主要创新之处在于,可以通过通用的数学公式分析在不同边界载荷作用下嵌入压电磁材料的多种几何形状和多层配置。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemMAGNETDeform振动通用材料控制
著作权归作者所有,欢迎分享,未经许可,不得转载
首次发布时间:2024-11-15
最近编辑:8天前
Tansu
签名征集中
获赞 3粉丝 0文章 690课程 0
点赞
收藏
作者推荐

【新文速递】2024年11月7日复合材料SCI期刊最新文章

今日更新:Composites Part B: Engineering 11 篇Composites Part B: EngineeringExploring ultrasonic and resistance welding for thermoplastic composite structures: Process development and application potentialLars Larsen, Manuel Endrass, Stefan Jarka, Simon Bauer, Maximilian Janekdoi:10.1016/j.compositesb.2024.111927热塑性复合材料结构的超声和电阻焊探索:工艺发展和应用潜力Thermoplastic composites outperform in aerospace applications compared to thermoset composites due to their weldability, a key advantage. This feature streamlines manufacturing, allowing for precise assembly of complex shapes, reducing costs, and accelerating production. Additionally, it simplifies maintenance, enabling easy repair or replacement of damaged parts, thereby extending vehicle lifespan and minimizing downtime. With exceptional strength-to-weight ratio and resistance to corrosion and fatigue, weldable thermoplastic composites ensure reliable performance in the demanding aerospace environment. Overall, their weldability enhances efficiency, versatility, and safety in aerospace applications. This paper first presents an overview of various welding processes and discusses the special challenges of assembly processes in the aviation industry. This work then focuses from the authors’ perspective with regard to industrializability on the two most promising processes, resistance and ultrasonic welding.与热固性复合材料相比,热塑性复合材料在航空航天应用中的表现优于热固性复合材料,因为它们的可焊性是一个关键优势。该功能简化了制造,允许复杂形状的精确组装,降低了成本,加快了生产。此外,它简化了维护,使维修或更换损坏的部件变得容易,从而延长了车辆的使用寿命并最大限度地减少了停机时间。可焊接热塑性复合材料具有卓越的强度重量比和耐腐蚀和抗疲劳性能,可确保在苛刻的航空航天环境中具有可靠的性能。总的来说,它们的可焊性提高了航空航天应用的效率、通用性和安全性。本文首先概述了各种焊接工艺,并讨论了航空工业中装配工艺的特殊挑战。这项工作然后从作者的角度关注两种最有前途的工艺的工业化,电阻和超声波焊接。“Janus” PEEK Implant with Sandwich Mg-Containing Coating for Infected Tissue RepairXingdan Liu, Haifeng Zhang, Ji Tan, Ziyi Lu, Xiaochun Peng, Liping Ouyang, Xuanyong Liudoi:10.1016/j.compositesb.2024.111938 夹心含镁涂层的“Janus”PEEK植入物用于感染组织修复Having good antibacterial properties and promoting soft and hard tissue repair are the keys to successful implantation of intraosseous transcutaneous. Polyether ether ketone (PEEK) is a class of FDA-approved polymer implants. However, the surface of PEEK is bioinert, which is easy to cause postoperative infection and poor tissue integration. In this study, polypyrrole (Ppy) was polymerized on sulfonated PEEK, Mg3(PO4)2 nanosheets were grown in situ on one side, and polycaprolactone (PCL) was then spun on the surface to form a Janus-like surface on PEEK. The Ppy/Mg3(PO4)2/PCL composite coating could inhibit bacterial adhesion, and the excellent photothermal properties of Ppy/Mg3(PO4)2/PCL and Ppy coatings further promote the removal of bacteria due to the accumulated heat. After the infection was eliminated, the Janus-like surface of modified PEEK switched macrophages to anti-proinflammatory response and promoted both soft and hard tissue repair. The Ppy modified sulfonated PEEK could promote collagen secretion in the soft tissue, while the PCL films on Ppy/Mg3(PO4)2/PCL was densified by temperature response under near-infrared light treatment to close the exposed interface of Mg3(PO4)2 nanosheets that was more conducive to bone repair. In summary, PEEK with Janus-like surface consisting of Ppy/Mg3(PO4)2/PCL and Ppy has multiple biological functions of sequential antibacterial and soft and hard tissue repair, and is a promising candidate material for intraosseous transcutaneous implants.具有良好的抗菌性能和促进软硬组织修复是骨内经皮植入成功的关键。聚醚醚酮(PEEK)是一类经fda批准的聚合物植入物。但PEEK表面具有生物惰性,易引起术后感染,组织整合性差。在本研究中,聚吡啶(Ppy)在磺化PEEK上聚合,Mg3(PO4)2纳米片在一侧原位生长,聚己内酯(PCL)在PEEK表面旋转形成Janus-like表面。Ppy/Mg3(PO4)2/PCL复合涂层可以抑制细菌粘附,并且Ppy/Mg3(PO4)2/PCL和Ppy涂层优异的光热性能进一步促进了细菌因积热而被去除。感染消除后,改性PEEK的janus样表面使巨噬细胞产生抗促炎反应,促进软硬组织修复。Ppy修饰的磺化PEEK可以促进软组织中胶原的分泌,而在近红外光处理下,Ppy/Mg3(PO4)2/PCL上的PCL膜通过温度响应致密化,关闭Mg3(PO4)2纳米片暴露的界面,更有利于骨修复。综上所述,由Ppy/Mg3(PO4)2/PCL和Ppy组成的Janus-like surface PEEK具有顺序抗菌和软硬组织修复等多种生物学功能,是一种很有前景的经皮骨内植入材料。Laser powder bed fusion of high-strength crack-free Al7075 alloy with the in-situ formation of TiB2/Al3Ti-reinforced phases and nucleation agentsYanzhen Liang, Quanquan Han, Zhongyang Sui, Zhenhua Zhang, Han Zhang, Heng Gu, Defan Wu, Liqiao Wang, Hanlian Liu, Rossitza Setchidoi:10.1016/j.compositesb.2024.111940激光粉末床熔接高强无裂纹Al7075合金,原位形成TiB2/ al3ti增强相和成核剂The existence of solidification cracks caused by columnar grains in precipitation-hardened aluminium alloys limit the applicability of Al7075 components manufactured via laser powder bed fusion (LPBF) additive manufacturing. A novel approach was developed to co-incorporate submicron-sized B and micron-grade Ti6Al4V to eliminate hot cracks and to effectively transform coarse columnar grains into fine equiaxed grains, thus improving the mechanical performance of LPBF-fabricated modified Al7075 material. The grain refinement was mainly attributable to the heterogeneous nucleation promoted by the combination of in-situ-formed L12-Al3Ti and TiB2 nano-sized phases. After an optimised T6 heat treatment, excellent comprehensive mechanical properties were achieved, with a tensile strength of 460 MPa and an elongation of 13%. This research provides an efficient and cost-effective path for addressing crack-sensitive metallic materials used for LPBF additive manufacturing processes.析出硬化铝合金中存在由柱状晶粒引起的凝固裂纹,限制了激光粉末床熔合(LPBF)增材制造Al7075部件的适用性。提出了一种将亚微米级B和微米级Ti6Al4V共掺杂的新方法,以消除热裂纹,并有效地将粗柱状晶粒转变为细等轴晶粒,从而提高lpbf制备的改性Al7075材料的力学性能。晶粒细化的主要原因是原位形成的L12-Al3Ti和TiB2纳米相结合促进了晶粒的非均相形核。经过优化的T6热处理后,获得了优异的综合力学性能,抗拉强度为460 MPa,伸长率为13%。该研究为解决用于LPBF增材制造工艺的裂纹敏感金属材料提供了一种高效且经济的途径。Vine-inspired 3D self-supporting spiral networks enable all-polymer composites advanced dielectric properties and isotropic thermal managementQibin Xu, Shengchang Zhang, Yingying Zhao, KaiXiang Wang, Shuheng Liang, Yuanyuan Yu, Yan Jiang, Baolong Xue, Mengjin Jiang, Pengqing Liudoi:10.1016/j.compositesb.2024.111942 葡萄藤启发的3D自支撑螺旋网络使全聚合物复合材料具有先进的介电性能和各向同性热管理Traditionally, it has been considered impossible to overcome the directional limitations associated with polarization and thermal conductivity (λ) in laminated all-polymer composites, which are essential for signal transmission and heat dissipation in fifth-generation equipment shells. Herein, by utilizing hierarchical weaving technology, a vine-like three-dimensional (3D) ultrahigh molecular weight polyethylene (UHMWPE) spiral network is created in laminated ramie-reinforced composites. This unique spiral structure ensures polarization balance by continuously dispersing functional UHMWPE crystals in multiple directions, and it safeguards the micro/nanopores (air carriers) of ramie through self-support, thereby achieving exceptional microwave transmittance (98.3 %). Remarkably, this structure effectively overcomes the limitations of thermal paths in laminated composites along their vertical plane directions, thus simultaneously obtaining high in-plane λ (3.3354 W/mK) and through-plane λ (3.2756 W/mK). This novel approach based on a functional crystal-based 3D spiral network challenges the stereotypes regarding all-polymer composites, particularly in terms of advanced dielectric properties and isotropic thermal management.传统上,人们认为不可能克服层压全聚合物复合材料中与极化和导热系数(λ)相关的方向限制,而这对于第五代设备外壳的信号传输和散热至关重要。本文利用分层编织技术,在层叠苎麻增强复合材料中创建了藤蔓状三维超高分子量聚乙烯(UHMWPE)螺旋网络。这种独特的螺旋结构通过在多个方向上连续分散功能性超高分子量聚乙烯晶体来确保极化平衡,并通过自支撑来保护苎麻的微/纳米孔(空气载体),从而实现优异的微波透过率(98.3%)。值得注意的是,这种结构有效地克服了层合复合材料沿垂直方向热路径的限制,从而同时获得高的面内λ (3.3354 W/mK)和通面λ (3.2756 W/mK)。这种基于功能晶体三维螺旋网络的新方法挑战了关于全聚合物复合材料的刻板印象,特别是在先进的介电性能和各向同性热管理方面。hUCMSC-derived exosomes mitigate blood-spinal cord barrier disruption by activating AMPK/mTOR-mediated autophagic flux after acute spinal cord injuryZhiheng Chen, Shengting Wu, Shihao Sheng, Sicheng Wang, Yuxuan Qian, Xin Wang, Fengjie Lu, Qi Han, Xiao Chen, Jiacan Su, Xiaofeng Liandoi:10.1016/j.compositesb.2024.111944 急性脊髓损伤后,hucmsc衍生的外泌体通过激活AMPK/ mtor介导的自噬通量来减轻血脊髓屏障破坏After spinal cord injury (SCI), the integrity of the blood-spinal cord barrier (BSCB) can be disrupted, leading to the secondary injuries such as inflammatory cell infiltration, neuronal death, and spinal cord hematoma. It is important to maintain the integrity of the BSCB to help restore function following SCI. While some studies have demonstrated the therapeutic effects of exosomes derived from human umbilical cord mesenchymal stem cells (hUCMSC-exos), their role in preserving BSCB integrity remains unclear. In our study, we demonstrated the protective effects of hUCMSC-exos on the BSCB and its mechanism. The results of this study indicate that hUCMSC-exos promote motor function recovery, preserve spinal cord structure, and reduce neuronal loss by inhibiting BSCB leakage following SCI. Experimental investigations conducted in vivo and in vitro have demonstrated that hUCMSC-exos can mitigate the loss of adherens junctions (AJs) and tight junctions (TJs) and stimulate autophagy in spinal cord endothelial cells. The protective effects were also found to be significantly reversed following the inhibition of autophagy using 3-MA. In conclusion, our study demonstrates that hUCMSC-exos protect the integrity of BSCB by promoting the repair of spinal endothelial cells through activation of autophagy, thereby exerting a protective role in SCI.脊髓损伤(SCI)后,血脊髓屏障(BSCB)的完整性可被破坏,导致炎症细胞浸润、神经元死亡、脊髓血肿等继发性损伤。维持BSCB的完整性对于帮助脊髓损伤后的功能恢复是很重要的。虽然一些研究已经证明了来自人脐带间充质干细胞(hUCMSC-exos)的外泌体的治疗作用,但它们在保持BSCB完整性方面的作用尚不清楚。在我们的研究中,我们证明了hUCMSC-exos对BSCB的保护作用及其机制。本研究结果表明,humcc -exos通过抑制脊髓脊髓液渗漏,促进运动功能恢复,保护脊髓结构,减少神经元损失。体内和体外实验研究表明,hUCMSC-exos可以减轻粘附连接(AJs)和紧密连接(TJs)的丢失,并刺 激脊髓内皮细胞的自噬。在使用3-MA抑制自噬后,这种保护作用也被发现明显逆转。综上所述,我们的研究表明,hUCMSC-exos通过激活自噬来促进脊髓内皮细胞的修复,从而保护BSCB的完整性,从而在脊髓损伤中发挥保护作用。Mechanical and Electromagnetic Interference Shielding Properties of In-situ Grown Si3N4nw Synergistic Defective-Graphene Reinforced Alumina CeramicsYameng Jiao, Qiang Song, Xu Yang, Liyuan Han, Caixiang Xiao, Fei Zhao, Hejun Lidoi:10.1016/j.compositesb.2024.111945原位生长Si3N4nw协同缺陷-石墨烯增强氧化铝陶瓷的机械和电磁干扰屏蔽性能Ceramic matrix composites have versatile application potential but are astricted by brittleness and single function. It can be ameliorated assisted by reinforcements, but the uneven distribution of reinforcements seriously limits the reinforcing efficiency. In this work, the layered porous skeleton of alumina (Al2O3) and silicon dioxide (SiO2) was prepared, then defective-graphene (DG) and silicon nitride nanowires (Si3N4nw) were successively grown in-situ in the skeleton to concurrently strength and toughen, as well as endow Al2O3 ceramic with electromagnetic interference (EMI) shielding performance. Subsequently, Al2O3/SiO2-G-Si3N4nw preform was sintered to construct a uniform Si3N4nw synergistic DG enhancement network. The optimum flexural strength and fracture toughness of the sintered ceramic reached 388.52 MPa and 11.29 MPa∙m1/2, respectively. This was mainly since DG can fine the ceramic grains, induce crack deflection and furcation, while the uniformly distributed Si3N4nw consumed additional energy during the pull-out process. In addition, the EMI shielding effectiveness of the sintered ceramics in X-band was up to 31.77 dB, which is mainly attributed to the conductive loss, dipole polarization loss and interfacial polarization loss of DG. Remarkably, this work provides an idea for efficient strengthening, toughening and integration of structure and function.陶瓷基复合材料具有广泛的应用潜力,但受脆性和单一功能的限制。在加固的辅助下,加固效果可以得到改善,但加固分布不均匀严重限制了加固效果。本工作制备了氧化铝(Al2O3)和二氧化硅(SiO2)的层状多孔骨架,然后在骨架中依次原位生长缺陷石墨烯(DG)和氮化硅纳米线(Si3N4nw),以同时增强和增韧,并赋予Al2O3陶瓷具有电磁干扰(EMI)屏蔽性能。随后,烧结Al2O3/SiO2-G-Si3N4nw预制体,构建均匀的Si3N4nw协同DG增强网络。烧结陶瓷的最佳抗弯强度和断裂韧性分别达到388.52 MPa和11.29 MPa∙m1/2。这主要是因为DG可以细化陶瓷晶粒,诱导裂纹偏转和分叉,而均匀分布的Si3N4nw在拔出过程中会消耗额外的能量。此外,烧结陶瓷在x波段的电磁干扰屏蔽效能高达31.77 dB,这主要归因于DG的导电损耗、偶极极化损耗和界面极化损耗。值得注意的是,这项工作为结构和功能的有效强化、增韧和整合提供了思路。Frequency insensitive electromagnetic absorption core-shell sandwich structure with excellent electromagnetic damage toleranceYiming Zhao, Suli Xing, Changliang Li, Naifeng Yang, Yonglyu He, Ke Duan, Jianwei Zhangdoi:10.1016/j.compositesb.2024.111946 频率不敏感电磁吸收芯壳夹层结构,具有优异的电磁损伤容忍度The compatibility of broadband electromagnetic absorption and electromagnetic damage tolerance poses challenges to the regulation of electromagnetic response characteristics, which are typically restricted by the intrinsic dispersion of materials and strong resonant features of unit cell structures. In this work, triply-periodic-minimal-surfaces (TPMS) based gradient core-shell sandwich structure is proposed to address this challenge for its mathematical defined unique conductive pore structure. The reflection loss-frequency curve is less than -10 dB in 2-18 GHz frequency band, accompanied by two separate resonant absorption peaks at 2.4 GHz and 17.5 GHz. The reflection loss curve is insensitive to frequency in a wide frequency band of 4-14 GHz, using merely three kinds of absorbing materials. When the damage proportion is less than 40%, effective electromagnetic absorption can be maintained in panel damage, core damage and penetrating damage modes, thanks to the extraordinary conduction-dissipation effect. Our study provides valuable insights for the design of damage tolerant electromagnetic absorption structures.宽带电磁吸收和电磁损伤容限的兼容性对电磁响应特性的调节提出了挑战,而电磁响应特性的调节通常受到材料的本征色散和单胞结构的强谐振特性的限制。在这项工作中,提出了基于三周期最小表面(TPMS)的梯度核壳夹层结构,以其数学定义的独特导电孔隙结构来解决这一挑战。在2 ~ 18 GHz频段,反射损耗频率曲线小于-10 dB,在2.4 GHz和17.5 GHz频段存在两个独立的共振吸收峰。在4 ~ 14ghz宽频带内,仅使用三种吸波材料,反射损耗曲线对频率不敏感。当损伤比例小于40%时,由于超常的传导耗散效应,在面板损伤、铁芯损伤和穿透损伤模式下均能保持有效的电磁吸收。我们的研究为容损电磁吸收结构的设计提供了有价值的见解。Interfacial property optimization through the co-deployment of MOF-derived nickel phyllosilicate and DOPO: Effective reinforcement and flame retardancy of epoxy resinShibin Nie, Zongquan Zhao, Wenli Zhai, Jinian Yang, Hong Zhang, Dongyue Zhao, Jingwen Wangdoi:10.1016/j.compositesb.2024.111947 mof衍生的层状硅酸镍和DOPO共配优化界面性能:环氧树脂的有效增强和阻燃Epoxy resin (EP) is a versatile material widely employed in diverse fields such as electronic encapsulation, coatings, and adhesives. The optimization of flame-retardant, mechanical and interfacial properties in composites through material modification and compounding represents a prominent research focus within the field of EP. This study presents a novel approach by synthesizing MOF-derived nickel phyllosilicate (K-NiPS) and compounding it with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) into the EP matrix. The incorporation of 5 wt% total K-NiPS and DOPO, with a mass ratio of 2:3, achieves a UL-94 V-0 rating and enhances the limiting oxygen index from 23.5 to 28.8%. This combination also reduced the peak heat release rate, peak smoke release rate, and total smoke release by 44.6%, 53.6%, and 37.8% respectively. Besides, the interface optimization effect of K-NiPS in collaboration with DOPO improved the tensile strength of EP/2K-NiPS/3DOPO from 77.5 MPa to 94.3 MPa, and the wear rate was only 1.25 × 10-5 mm3/(N·m), which is 82.2% lower than that of pure EP. This study will pave the way for the applied interface design of multi-functional EP.环氧树脂(EP)是一种用途广泛的材料,广泛应用于电子封装、涂料、粘合剂等领域。通过材料改性和复合来优化复合材料的阻燃性能、力学性能和界面性能是EP领域的一个突出研究热点。本研究提出了一种合成mof衍生的叶状硅酸镍(K-NiPS)的新方法,并将其与9,10-二氢-9-氧-10-磷酸菲-10-氧化物(DOPO)复配到EP基质中。总K-NiPS和DOPO的掺入量为5 wt%,质量比为2:3,达到UL-94 V-0等级,并将极限氧指数从23.5提高到28.8%。该组合还使峰值放热率、峰值放烟率和总放烟率分别降低了44.6%、53.6%和37.8%。此外,K-NiPS与DOPO协同作用的界面优化效果使EP/2K-NiPS/3DOPO的抗拉强度从77.5 MPa提高到94.3 MPa,磨损率仅为1.25 × 10-5 mm3/(N·m),比纯EP降低82.2%。本研究将为多功能EP的应用界面设计奠定基础。Highly deformable self-sensing cementitious composites enabled by monomer polymerization for full-scale shear wall seismic monitoringNanxi Dang, Chengji Xu, Dan Yu, Jiayi Tu, Wei Zhu, Jiyang Wang, Qiang Zeng, Weijian Zhaodoi:10.1016/j.compositesb.2024.111948高变形自传感胶凝复合材料单体聚合实现全尺寸剪力墙地震监测Cementitious composites generally possess high brittleness and low deformability, which greatly limits their engineering applications. Herein, we proposed a method of in-situ polymerization of sodium acrylate (SA) monomers in cement matrix to fabricate highly deformable self-sensing cementitious composites (HD-SSCC) with graphene nanoplatelets (GNP). Engineering performances, sensibility and multi-scale structures of the HD-SSCC specimens were tested. Results demonstrate that the HD-SSCC specimens possessed superior water resistivity, strength and deformability. Specifically, the HD-SSCC with 4% SA showed the increases of flexural strength and compression strength by 139% and 50%, and the improvement of fractional change in resistance (FCR) by almost 6 times. The cement hydrates, polyacrylate and GNP jointly built a composite structure that strengthens the cement matrix and enhances the sensibility. An HD-SSCC assembly was installed in a full-scale shear wall for seismic monitoring, which shows excellent sensibility at low loading stage. Our findings provide a simple way towards low-cost yet high-strength SSCC for structural health monitoring.胶凝复合材料普遍具有脆性高、变形能力低的特点,极大地限制了其工程应用。在此,我们提出了一种在水泥基体中原位聚合丙烯酸钠(SA)单体的方法,以制备具有石墨烯纳米片(GNP)的高变形自传感胶凝复合材料(HD-SSCC)。对HD-SSCC试件的工程性能、敏感性和多尺度结构进行了测试。结果表明,HD-SSCC试样具有优异的水阻、强度和变形性能。其中,添加4% SA的HD-SSCC的抗弯强度和抗压强度分别提高了139%和50%,阻力分数变化(FCR)改善了近6倍。水泥水合物、聚丙烯酸酯和GNP共同构成复合结构,强化水泥基体,增强敏感性。HD-SSCC组件安装在全尺寸剪力墙中进行地震监测,在低荷载阶段表现出良好的灵敏度。我们的发现为低成本、高强度的SSCC结构健康监测提供了一种简单的方法。Electrophoretic deposition of curcumin-loaded mesoporous bioactive glass nanoparticle-chitosan composite coatings on titanium for treating tumor-induced bone defectYuhan Zhang, Jingjie Yu, Chenhuan Wu, Lehao Han, Yunru Tai, Boyan Wang, Yujing Yan, Yekai Liu, Yihan Sun, Qinqin Lu, Kai Zheng, Tian Zhou, Qiang Chendoi:10.1016/j.compositesb.2024.111950 负载姜黄素的介孔生物活性玻璃纳米颗粒-壳聚糖复合涂层在钛上的电泳沉积治疗 肿瘤性骨缺损Clinical treatment of osteosarcoma (OS) presents significant challenges in postoperative tumor recurrence and large segmental bone defects, often necessitating joint replacement or artificial bone implantation to repair failed or defective bone tissue. At the same time, fibroblastic encapsulation can impede direct contact between implants and bones, leading to implant failure. To tackle these issues, mesoporous bioactive glass nanoparticles (MBN) were synthesized and then loaded with curcumin (CUR). Subsequently, chitosan (CTS) was chosen as the charger and coating matrix, and electrophoretic deposition (EPD) was utilized to fabricate a CTS-MBN-CUR composite coating with triple functionality on Ti implants aiming for OS-induced bone repair. MBN-CUR nanoparticles are encapsulated in CTS and uniformly distributed within the coating, achieving robust adhesion and long-term release of CUR. Concurrently, the developed CTS-MBN-CUR coating exhibits moderate hydrophilicity, and good bioactivity. Moreover, three different types of cells, MC3T3-E1, L929, and MG63 cells, were individually cultured with the composite coating and subjected to comprehensive cellular studies. The coating presented favorable bioactivities, and osteogenic performance, and the ability to resist the activity of fibroblast and OS cells. These findings suggest that CTS-MBN-CUR holds promising potential for bone regeneration following OS resection surgery.骨肉瘤(osteosarcoma, OS)的临床治疗面临着术后肿瘤复发和大节段性骨缺损的重大挑战,通常需要关节置换或人工骨植入来修复失败或缺陷的骨组织。同时,纤维母细胞包封会阻碍种植体与骨骼的直接接触,导致种植体失效。为了解决这些问题,合成了介孔生物活性玻璃纳米粒子(MBN),然后负载姜黄素(CUR)。随后,选择壳聚糖(CTS)作为充电剂和涂层基质,利用电泳沉积(EPD)法制备了具有三功能的CTS- mbn - cur复合涂层,用于钛种植体os诱导的骨修复。MBN-CUR纳米颗粒被包裹在CTS中,并均匀分布在涂层内,实现了优异的黏附和长效释放,同时所制备的CTS-MBN-CUR涂层具有中等亲水性和良好的生物活性。此外,将MC3T3-E1、L929和MG63三种不同类型的细胞分别用复合涂层培养,并进行全面的细胞研究。该涂层具有良好的生物活性和成骨性能,并能抵抗成纤维细胞和骨肉瘤细胞的活性。这些研究结果表明,CTS-MBN-CUR具有骨切除术后骨再生的良好潜力。Carbon nanotube intermediate layer intercalation and its influence on surface charge of thin film composite membraneLuyao Deng, Ralph Rolly Gonzales, Joy Thomas, Ryosuke Takagi, Wenming Fu, Cheng-Liang Liu, Shang Xiang, Hideto Matsuyamadoi:10.1016/j.compositesb.2024.111951 碳纳米管中间层嵌入及其对薄膜复合膜表面电荷的影响The surface charge of a separation membrane is a critical factor affecting its performance in ion separation and fouling resistance. Thin-film composite (TFC) polyamide (PA) membrane, commonly used in water treatment, often suffer from excessive surface negative charges, which significantly limits their application and fouling resistance. To address this issue, this work introduces a carbon nanotubes (CNT) intermediate layer to adjust the surface charge of TFC PA membranes, aiming to achieve a PA layer with neutral properties. Novel grazing-incidence wide-angle x-ray scattering (GIWAXS) measurements were employed to elucidate the effect of CNT on the molecular chain stacking of PA. The CNT intermediate layer was found to influence the PA cross-linking, which is related to surface negative charge, by controlling the storage and release of the m-phenylenediamine monomer during interfacial polymerization. The neutral CNT-TFC membrane demonstrated improved NH4 + retention and increased resistance to fouling by protein, surfactant, and E. coli. However, other surface properties, such as roughness and hydrophilicity, could counteract the antifouling benefits of a neutral surface. This work provides insights into additional advantages of CNT intermediate layer intercalation in TFC PA membranes, such as enhanced cross-linking and surface charge control.分离膜的表面电荷是影响其离子分离性能和抗污染性能的关键因素。薄膜复合材料(TFC)聚酰胺(PA)膜是水处理中常用的一种膜材料,其表面负电荷过多,严重限制了其应用和抗污性能。为了解决这一问题,本工作引入了碳纳米管(CNT)中间层来调节TFC PA膜的表面电荷,旨在实现具有中性特性的PA层。采用新型掠入射广角x射线散射(GIWAXS)测量方法研究了碳纳米管对聚酰胺分子链堆积的影响。在界面聚合过程中,碳纳米管中间层通过控制间苯二胺单体的储存和释放来影响与表面负电荷有关的聚丙烯腈交联。中性碳纳米管- tfc膜表现出改善的NH4 +潴留和增强的抵抗蛋白质、表面活性剂和大肠杆菌的污染。然而,其他表面特性,如粗糙度和亲水性,可能会抵消中性表面的防污作用。这项工作为碳纳米管中间层嵌入TFC PA膜的其他优点提供了见解,例如增强交联和表面电荷控制。来源:复合材料力学仿真Composites FEM

未登录
还没有评论
课程
培训
服务
行家
VIP会员 学习 福利任务 兑换礼品
下载APP
联系我们
帮助与反馈