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【新文速递】2024年1月11日固体力学SCI期刊最新文章

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今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Correlation between surface-to-volume ratio of the particle shape and elastic properties of the particulate composites

Pascal Alexander Happ, Romana Piat

doi:10.1016/j.ijsolstr.2024.112658

颗粒形状的表面体积比与颗粒复合材料弹性特性之间的相关性

This work is motivated by real-world particle shapes, observed using a scanning electron microscopy. The focus of the presented studies was to understand the effects of the particle shapes on the effective elastic properties of the two-phase composites. For this, particles with polyhedral, undulated and other shapes were numerically modeled using analytical functions. Creation of some shapes, like polyhedral, are known from the literature but Laplace’s spherical harmonics, as well as the Goursat’s surface and some others, were used for the first time to create novel particle shapes. Elastic properties of the composites with different particle shapes were calculated using the finite element analysis. The obtained results show good agreement with mean-field homogenization methods such like Mori-Tanaka and Lielens as well as other numerical results available in the literature. Further, the dependence of the effective Young’s moduli of the composite on the shape and the corresponding surface-to-volume ratio of the particles was studied. It was observed that the effective Young’s moduli increase with the surface-to-volume ratio of the particles in the case where particles are stiffer in comparison to the matrix. It was also remarked that, in the case of particles of similar shapes, the particle surface-to-volume ratio and the effective Young’s moduli differ significantly with the surface curvature and the edge sharpness of the particles.

这项工作的动力来自于使用扫描电子显微镜观察到的真实颗粒形状。本研究的重点是了解颗粒形状对两相复合材料有效弹性特性的影响。为此,使用分析函数对多面体、波状和其他形状的颗粒进行了数值建模。一些形状(如多面体)的创建已从文献中获知,但拉普拉斯球面谐波以及 Goursat 曲面和其他一些形状是首次用于创建新颖的颗粒形状。使用有限元分析计算了不同颗粒形状的复合材料的弹性特性。所得结果与 Mori-Tanaka 和 Lielens 等平均场均质化方法以及文献中的其他数值结果显示出良好的一致性。此外,还研究了复合材料的有效杨氏模量与颗粒形状和相应的表面体积比的关系。研究发现,在颗粒与基体相比更硬的情况下,有效杨氏模量随颗粒的表面体积比增加而增加。研究还注意到,在颗粒形状相似的情况下,颗粒表面体积比和有效杨氏模量随颗粒表面曲率和边缘锐度的变化而显著不同。


Journal of the Mechanics and Physics of Solids

Grain boundary network plasticity: Reduced-order modeling of deformation-driven shear-coupled microstructure evolution

Daniel Bugas, Brandon Runnels

doi:10.1016/j.jmps.2024.105541

晶界网络塑性:变形驱动剪切耦合微结构演化的降阶建模

Microstructural evolution in structural materials is known to occur in response to mechanical loading and can often accommodate substantial plastic deformation through the coupled motion of grain boundaries (GBs). This can produce desirable behavior, such as increased ductility, or undesirable behavior such as mechanically-induced coarsening. In this work a novel, multiscale model is developed for capturing the combined effect of plasticity mediated by multiple GBs simultaneously. This model is referred to as “grain boundary network plasticity.” The mathematical framework of graph theory is used to describe the microstructure connectedness, and the evolution of microstructure is represented as volume flow along the graph. By using the principle of minimum dissipation potential, which has previously been applied to grain boundary migration, a set of evolution equations are developed that transfer volume and eigendeformation along the graph edges in a physically consistent way. It is shown that higher-order geometric effects, such as the pinning effect of triple points, may be accounted for through the incorporation of a geometric hardening that causes geometry-induced GB stagnation. The result is a computationally efficient reduced order model that can be used to simulate the initial motion of grain boundaries in a polycrystal with parameters informed by atomistic simulations. The effectiveness of the model is demonstrated through comparison to multiple bicrystal atomistic simulations, as well as a select number of GB engineered and non-GB engineered data obtained from the literature. The effect of the network of shear-coupling grain boundaries is demonstrated through mechanical response tests and by examining the yield surfaces.

众所周知,结构材料的微观结构演变是对机械负载的响应,通常可通过晶界(GB)的耦合运动产生大量塑性变形。这可能产生理想的行为,如增加延展性,也可能产生不理想的行为,如机械引起的粗化。本研究开发了一种新型多尺度模型,可同时捕捉多个 GB 介导的塑性综合效应。该模型被称为 "晶界网络塑性"。该模型采用图论的数学框架来描述微观结构的连通性,并将微观结构的演变表示为沿图的体积流。利用之前应用于晶界迁移的最小耗散势原理,建立了一组演化方程,以物理一致的方式沿图边传递体积和特征变形。研究表明,高阶几何效应(如三重点的针销效应)可以通过加入几何硬化来解释,几何硬化会导致几何诱导的 GB 停滞。结果是一个计算效率高的降阶模型,可用于模拟多晶体中晶界的初始运动,其参数由原子模拟提供。通过与多个双晶原子模拟以及从文献中获取的部分 GB 工程和非 GB 工程数据进行比较,证明了该模型的有效性。通过机械响应测试和屈服面检查,证明了剪切耦合晶界网络的效果。


Mechanics of Materials

Constitutive models for confined elastomeric layers: Effects of nonlinearity and compressibility

Sida Hao, Rui Huang, Gregory J. Rodin

doi:10.1016/j.mechmat.2024.104912

约束弹性层的构造模型:非线性和可压缩性的影响

Elastomers tend to undergo large deformations accompanied by small volumetric changes. For elastomeric layers sandwiched between rigid plates, large deformations can be significantly limited by the constraints imposed by the plates. Further, those constraints can be enhanced by material’s inability to undergo large volumetric changes. From this perspective, it is appropriate to examine the validity of constitutive models, in which an elastomer is treated as incompressible, for analysis of the confined layers. Here, this issue is addressed by considering the mechanical response of sandwiched elastomeric layers using three constitutive models. The first one, referred to as compressible neo-Hookean, is regarded as exact. The other two models are regarded as approximations. Of those two, the first one neglects nonlinearity and the second one neglects compressibility. Accordingly, the modeling errors associated with the former are treated as measures of importance of nonlinearity, and the modeling errors associated with the latter are treated as measures of importance of compressibility. The modeling errors are evaluated using the force–displacement curve and the mean stress at the layer center as the quantities of interest. Numerical results are presented for rubber and polydimethylsiloxane (PDMS), characterized by Poisson’s ratios ν=0.4999 and ν=0.49, respectively. It is shown that, even when the forces applied to the plates are large, considering nonlinearity is important for thick but not for thin layers. In contrast, considering compressibility is important for thin layers. The need for considering compressibility is further assessed by introducing a competition parameter, which reinforces the notion that compressibility is important for modeling PDMS layers and thin rubber layers.

弹性体往往会发生较大的变形,同时伴随着较小的体积变化。对于夹在刚性板之间的弹性层来说,大变形可能会受到刚性板的严重限制。此外,由于材料无法发生大的体积变化,这些限制也会增强。从这一角度出发,研究将弹性体视为不可压缩的构成模型对分析约束层的有效性是合适的。在此,通过使用三种构成模型来考虑夹层弹性体层的机械响应,从而解决这一问题。第一个模型被称为可压缩新胡肯模型,是精确模型。其他两个模型被视为近似模型。在这两个模型中,第一个忽略了非线性,第二个忽略了可压缩性。因此,与前者相关的建模误差被视为非线性重要性的度量,与后者相关的建模误差被视为压缩性重要性的度量。使用力-位移曲线和层中心的平均应力作为相关量来评估建模误差。研究给出了橡胶和聚二甲基硅氧烷(PDMS)的数值结果,这两种材料的泊松比分别为 ν=0.4999 和 ν=0.49。结果表明,即使施加在板上的力很大,考虑非线性对厚层也很重要,但对薄层却不重要。相反,考虑可压缩性对薄层很重要。通过引入竞争参数,进一步评估了考虑可压缩性的必要性,从而加强了可压缩性对于 PDMS 层和薄橡胶层建模非常重要的观点。


International Journal of Plasticity

A continuum damage coupled unified viscoplastic model for simulating the mechanical behaviour of a ductile cast iron under isothermal low-cycle fatigue, fatigue-creep and creep loading

Michal Bartošák, Jakub Horváth

doi:10.1016/j.ijplas.2023.103868

用于模拟球墨铸铁在等温低循环疲劳、疲劳-蠕变和蠕变载荷下机械性能的连续损伤耦合统一粘塑模型

A novel continuum damage coupled unified viscoplastic model is used for simulating the stress–strain responses of SiMo 4.06 cast iron under Low-Cycle Fatigue (LCF), fatigue-creep and creep loading for temperatures up to 650 °C. The advanced constitutive model that is developed within the framework of the Chaboche model allows the simulation of various effects including strain rate sensitivity, cyclic hardening and softening, static recovery and strain range dependency. The hyperbolic sine flow rule and the static recovery of kinematic hardening rule are proposed in order to effectively simulate both stress relaxation and creep strains. The isotropic damage variable is introduced into the constitutive equations to represent the effects of material degradation. Three main damage mechanisms are considered: fatigue, creep and ductile damage. In addition, the model is further modified to take into account the progressive microdefects closure effect. Finally, the prediction capability of the proposed model is illustrated for the experimental data obtained from the various uniaxial material tests. A good correlation was achieved between the simulated and the experimental results.

采用新颖的连续损伤耦合统一粘塑模型模拟 SiMo 4.06 铸铁在低循环疲劳 (LCF)、疲劳-蠕变和蠕变载荷下的应力-应变响应,温度最高可达 650 °C。在 Chaboche 模型框架内开发的高级构成模型可模拟各种效应,包括应变速率敏感性、循环硬化和软化、静态恢复和应变范围依赖性。为了有效模拟应力松弛和蠕变应变,提出了双曲正弦流动规则和运动硬化静态恢复规则。在构成方程中引入了各向同性损伤变量,以表示材料退化的影响。模型考虑了三种主要损伤机制:疲劳损伤、蠕变损伤和韧性损伤。此外,还进一步修改了模型,以考虑渐进式微缺陷闭合效应。最后,针对从各种单轴材料试验中获得的实验数据,说明了所提模型的预测能力。模拟结果和实验结果之间实现了良好的相关性。


A computational mechanical constitutive modeling method based on thermally-activated microstructural evolution and strengthening mechanisms

Mingyu Lei, Guangpeng Sun, Guochun Yang, Bin Wen

doi:10.1016/j.ijplas.2024.103881

基于热激活微结构演化和强化机制的计算力学结构建模方法

A mechanical constitutive relationship is the basis for the design and application of structural materials, and the establishment of a mechanical constitutive relationship generally relies on experimental data. Herein a computational mechanical constitutive modeling method is proposed, in which all required parameters possess unambiguous physical interpretations and/or can be obtained from accurate numerical simulations. With the inclusion of interaction between dislocations and crystal defects, the dislocation density and grain size evolution with strain for polycrystalline metallic materials are mathematically modeled, and the corresponding contribution to strength is analysed, further a computational mechanical constitutive relationship can be obtained. Its effectiveness is verified by comparing it with experimental stress-strain relationships for Cu, Al-Mg, and Cu-W alloys. This method might be a powerful tool for the design of structural materials with desirable mechanical properties.

力学构成关系是结构材料设计和应用的基础,而力学构成关系的建立一般依赖于实验数据。本文提出了一种计算力学构成模型方法,其中所有必要参数都具有明确的物理解释和/或可从精确的数值模拟中获得。通过将位错与晶体缺陷之间的相互作用考虑在内,对多晶金属材料的位错密度和晶粒大小随应变的演变进行了数学建模,并分析了其对强度的相应贡献,从而进一步获得了计算力学组成关系。通过与铜、铝-镁和铜-钨合金的实验应力-应变关系进行比较,验证了该方法的有效性。这种方法可能是设计具有理想机械性能的结构材料的有力工具。


Thin-Walled Structures

Deformation behaviors of defective aluminum honeycomb sandwich panels subjected to in-panel compressive loading: an experimental study with mirror-assisted multi-view DIC

Kaiyu Zhu, Bing Pan

doi:10.1016/j.tws.2024.111592

缺陷铝蜂窝夹芯板在板内压缩载荷作用下的变形行为:利用镜像辅助多视角 DIC 进行的实验研究

Honeycomb sandwich panels have been extensively utilized in the aerospace and automotive industries for their prominent advantages of energy absorption, high strength and tailorable anisotropic mechanical properties. Nevertheless, the common presence of local core-to-skin disbonding poses an urgent need to understand the mechanical behaviors of defective honeycomb sandwich panels. The present work investigates the deformation behaviors and evolutions of aluminum honeycomb sandwich panels with varying sizes of circular artificial core-to-skin disbonding defects using mirror-assisted multi-view digital image correlation (MV-DIC). Based on the 3D profiles and dual-surface deformation fields obtained with mirror-assisted MV-DIC, it is revealed that disbonding defects induced local surface undulations with severe local strain concentrations and determined the mode of gradual bending and buckling. Defects with a diameter below 20 mm induced minor local surface undulations and slight decreases in buckling load. When the diameters of defects reach 30 mm, extensive surface convex deformation occurs and the buckling load decreases by 23%. The results validate mirror-assisted MV-DIC as a cost-effective and practical technique for characterizing dual-surface 3D deformation of sheet composite materials and structures.

蜂窝夹芯板具有能量吸收、高强度和可定制的各向异性机械性能等突出优势,已被广泛应用于航空航天和汽车行业。然而,由于普遍存在局部芯-皮脱粘现象,因此迫切需要了解有缺陷的蜂窝夹芯板的机械性能。本研究利用镜像辅助多视角数字图像相关(MV-DIC)技术,研究了存在不同大小的圆形人工芯-皮脱粘缺陷的铝蜂窝夹芯板的变形行为和演变过程。根据镜像辅助 MV-DIC 所获得的三维剖面和双表面变形场,可以发现脱粘缺陷会引起局部表面起伏,造成严重的局部应变集中,并决定了逐渐弯曲和屈曲的模式。直径小于 20 毫米的缺陷引起的局部表面起伏较小,屈曲载荷也略有下降。当缺陷直径达到 30 毫米时,会出现大面积的表面凹凸变形,屈曲载荷降低了 23%。这些结果验证了镜像辅助 MV-DIC 是表征片状复合材料和结构双表面三维变形的一种经济实用的技术。



来源:复合材料力学仿真Composites FEM
ACTMechanicalDeform疲劳复合材料非线性航空航天汽车电子UGUM化机材料多尺度试验曲面
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首次发布时间:2024-11-05
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【新文速递】2024年1月16日复合材料SCI期刊最新文章

今日更新:Composite Structures 3 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 1 篇Composite StructuresDynamic compression-shear ignition mechanism of Al/PTFE reactive materialsHengheng Geng, Rui Liu, Yeping Ren, Pengwan Chen, Chao Ge, Haifu Wangdoi:10.1016/j.compstruct.2024.117908Al/PTFE反应材料的动态压缩-剪切点火机理Ignition of Al/PTFE reactive materials can occur under dynamic loading. The ignition mechanism involves a mechanical-thermal-chemical coupled process, which draws the attention of scientists and engineers. However, it is difficult to understand the mechanism, especially under complex loadings. In this paper, three different shapes of Al/PTFE sample, 0° cylinder, 30° oblique cylinder and 45° oblique cylinder, were designed. The dynamic ignition tests were carried out by Split Hopkinson Pressure Bar (SHPB). The deformation, damage and fracture process were analyzed. The mechanical response depended on the shape of the sample, which determined the dynamic compression-shear states, further it induced different ignition behavior. The energy absorption rate ignition criterion was proposed to take the place of the traditional strain rate ignition criterion. The new criterion could match the testing well. In addition, numerical simulation on SHPB was conducted. It verified that Johnson-Cook model would describe the dynamic behavior of Al/PTFE reactive materials. The damage and the fracture of Al/PTFE under dynamic compression-shear loading was quantified well, and further was related to the ignition behavior observed during the tests. Finally, the dynamic compression-shear ignition mechanism of Al/PTFE reactive materials was revealed.铝/聚四氟乙烯反应材料在动载荷作用下会发生着火。引燃机理涉及一个机械-热-化学耦合过程,引起了科学家和工程师的关注。然而,很难理解其机理,特别是在复杂载荷下。本文设计了3种不同形状的Al/PTFE试样,分别为0°圆柱体、30°斜圆柱体和45°斜圆柱体。采用分离式霍普金森压杆(SHPB)进行了动态点火试验。对其变形、损伤和断裂过程进行了分析。试样的力学响应取决于试样的形状,这决定了试样的动态压剪状态,进而导致不同的着火行为。提出了能量吸收率点火判据,取代了传统的应变率点火判据。新的标准可以很好地与测试相匹配。此外,还对SHPB进行了数值模拟。验证了Johnson-Cook模型能够描述Al/PTFE反应材料的动力学行为。动态压剪载荷对Al/PTFE的损伤和断裂进行了较好的量化,并进一步与试验中观察到的着火行为有关。最后,揭示了Al/PTFE反应材料的动态压缩-剪切点火机理。Characterizing Damage Patterns and Evolution in Multi-Hole GLARE Laminates under Tensile Load via Integrated AE and DIC TechniquesY.X. Zheng, K.J. Hu, M. Zhang, J.X. Zhu, F.L. Zhao, W.Q. Han, Q.H. Shi, Z.L. Caodoi:10.1016/j.compstruct.2024.117911基于声发射和DIC集成技术表征拉伸载荷下多孔眩光层合板的损伤模式和演化In this study, a combined numerical simulation and experimental approach was employed to investigate the mechanical behavior and damage mechanisms of multi-hole GLARE laminates with varying off-axis angles under static tensile loading. Digital image correlation techniques were used to monitor changes in the strain field near the open hole region. The acoustic emission parameters were used to recognize damage patterns and evolution. The progressive damage evolution processes of various GLARE components were investigated using a 3D finite element model (FEM) based on the Hashin strain criterion and cohesive zone modeling. The results indicate that GLARE experiences damage modes such as aluminum alloy breakage, matrix cracking, fiber/matrix debonding, delamination, and fiber breakage. The frequency ranges associated with the five damage modes are as follows: [0-50 kHz], [100-175 kHz], [175-220 kHz], [220-300 kHz], and [300-400 kHz]. The dominant damage mode throughout the tensile phase is matrix cracking, but the ultimate failure of the specimen is determined by aluminum alloy breakage and fiber breakage. In addition, increasing the off-axis angle of the multi-hole leads to a shift in the final failure mode from tensile-dominated to tensile shear-dominated, while also slightly reducing the overall initial stiffness of the specimen.采用数值模拟与实验相结合的方法,研究了不同离轴角的多孔眩光层压板在静态拉伸载荷作用下的力学行为和损伤机理。利用数字图像相关技术监测裸眼区域附近应变场的变化。利用声发射参数识别损伤模式和演化过程。采用基于Hashin应变准则和黏聚区建模的三维有限元模型,研究了不同眩光组件的渐进损伤演化过程。结果表明,眩光材料经历了铝合金断裂、基体开裂、纤维/基体脱粘、分层和纤维断裂等损伤模式。与五种损伤模式相关的频率范围如下:[0-50 kHz], [100-175 kHz], [175-220 kHz], [220-300 kHz]和[300-400 kHz]。拉伸阶段的主要破坏方式是基体断裂,但最终破坏是由铝合金断裂和纤维断裂决定的。此外,增加多孔离轴角会导致最终破坏模式从拉伸为主转变为拉伸剪切为主,同时也会使试件的整体初始刚度略有降低。Auxetic Composite Absorbers based on foam-filled chiral frames for energy absorption in localized impactChuanqing Chen, Alessandro Airoldi, Antonio Maria Caporale, Giuseppe Sala, Xiaochun Yindoi:10.1016/j.compstruct.2024.117916基于泡沫填充手性框架的消声复合材料局部冲击吸能研究In this paper, an innovative concept is proposed, based on the hexachiral auxetic frames filled with foams with enhanced energy absorption capabilities. Numerical assessments of the composite foam-filled auxetic absorbers, of pure foam blocks and unfilled auxetic frames for metallic and polymeric material combinations were accomplished considering a case of localized impact. The energy absorbed by the composite absorbers are found superior to the sum of the energies absorbed by constituent elements tested separately with clear advantages also at the level of the specific energy absorbed per unit mass. The interactions between the two constituents are analyzed and discussed. An experiment considering a 3D-printed polymeric hexachiral frame filled with open-cell soft polyurethane foam under localized impact is conducted to validate the numerical approach. Eventually, a parametric sensitivity study is conducted numerically to illustrate the effects of geometrical parameters on the energy absorption capacity. Overall, the results confirm the potential and the great design flexibility of the concept, provides the guidelines to design advanced energy absorbing system, underlies the importance of the combination between the frame and foam properties and the effect of the main geometrical parameters on the performance.在此基础上,提出了一种具有增强吸能能力的泡沫填充六手性减振框架的创新概念。考虑局部碰撞情况,对金属和高分子材料组合的泡沫填充消声吸波器、纯泡沫块和未填充消声框架进行了数值评估。发现复合吸收剂吸收的能量优于单独测试的组成元素吸收的能量总和,在单位质量吸收的比能量水平上也具有明显的优势。分析和讨论了这两种成分之间的相互作用。以开孔软质聚氨酯泡沫塑料填充的3d打印聚合物六手体框架为研究对象,进行了局部冲击实验,验证了数值方法的有效性。最后,进行了参数敏感性数值研究,以说明几何参数对能量吸收能力的影响。总体而言,结果证实了这一概念的潜力和巨大的设计灵活性,为设计先进的吸能系统提供了指导,揭示了框架和泡沫性能之间结合的重要性以及主要几何参数对性能的影响。Composites Part B: EngineeringTowards sustainable reprocessable structural composites: Benzoxazines as biobased matrices for natural fibersGuillem Seychal, Louis Van Renterghem, Connie Ocando, Leila Bonnaud, Jean-Marie Raquezdoi:10.1016/j.compositesb.2024.111201迈向可持续的可再加工结构复合材料:苯并恶嗪作为天然纤维的生物基基质In this work, we synthesized and investigated three fully biobased benzoxazine matrices containing exchangeable ester bonds for natural fiber composites. The thermoset properties were investigated and the transesterification behavior was assessed. The obtained polymers show high tunability. Using isosorbide as the starting building block, the thermoset exhibits a glass transition of 130 °C, a tensile modulus of 2.5 GPa, and thermal stability leading to degradation occurring after 270 °C with 31% char at 800 °C. All formulations stress relax under catalyst-free conditions within an hour with properties recovery superior to 80%. Finally, flax composites were manufactured. We highlight strong affinities between the matrices and the fibers through high mechanical performances with a modulus over 30 GPa and stress at break of 400 MPa in the longitudinal direction. 5 GPa modulus and 47 MPa stress at break were found in the transverse direction. Excellent fire retardancy properties, with self-extinguishment and UL-94 V1 classification were obtained for the isosorbide-based/flax composite. The obtained composites were able to be welded with comparable results to glued ones, paving the way to processable laminates and stable cured prepreg perfectly suited for transportation-engineered applications.在这项工作中,我们合成并研究了三种含交换酯键的全生物基苯并恶嗪基天然纤维复合材料。对其热固性进行了研究,并对其酯交换行为进行了评价。所得聚合物具有较高的可调性。使用异山梨酯作为起始构件,热固性材料表现出130°C的玻璃化转变,拉伸模量为2.5 GPa,热稳定性导致270°C后发生降解,800°C下炭化31%。在无催化剂条件下,所有配方在1小时内应力松弛,性能恢复优于80%。最后,制备了亚麻复合材料。我们通过高力学性能(模量超过30 GPa,纵向断裂应力为400 MPa)突出了基质和纤维之间的强亲和力。横向模量为5 GPa,断裂应力为47 MPa。结果表明,异山梨酯基/亚麻复合材料具有良好的自熄性和UL-94 V1级阻燃性能。所获得的复合材料能够焊接,其结果与粘合的结果相当,为可加工的层压板和稳定的固化预浸料铺平了道路,非常适合运输工程应用。Engineered nanocomposites through embedding of smaller “organic inorganic” nanoparticles in thermoplastic Poly(2-Vinylpyridine) polymer matrixSanju Gupta, Alex Hensondoi:10.1016/j.compositesb.2024.111207通过在热塑性聚(2-乙烯基吡啶)聚合物基体中嵌入更小的“有机无机”纳米颗粒来设计纳米复合材料Polymer nanocomposites (PNCs) are significant for modern and future applications owing to their multifunctionality promoted by morphology and tailored interfaces between the constituents. However, ‘forward’ engineered polymer (host) composites with smaller size nanoparticles (guest) providing desired properties remains challenging as they depend upon nanoparticles aggregation, size, shape, and loading (volume or weight) fraction. This study strategically designs and develops PNCs comprising thermoplastic poly (2-vinylpyridine) (P2VP) polymer matrix impregnated with spherical polyhedral oligomeric silsesquioxane (N-POSS) nanoparticles (diameter ∼2–5 nm) and anisotropic planar nitrogenated graphene nanoribbons (GNR, strip width ∼5–10 nm) commensurate with polymer chain radius of gyration, Rg, (or segment length ∼1.5 nm) and comparable energy scales of electrostatic interaction and attractive hydrogen bonding. We investigated static and dynamic structure and thermophysical properties to correlate with interfacial regions and the results are compared with larger graphene oxide (GO, lateral dimension ∼100–200 nm) nanosheets and silica (SiO2, ∼25–50 nm) particles. While electron microscopy revealed nanoparticle distribution, the lattice bonding, conjugation length, and mechanical properties are determined from micro-Raman spectroscopy and atomic force microscopy, respectively. The differential scanning calorimetry provided a measure of glass transition temperature, Tg, with positive shift of ∼10–18 °C with nanoparticles loading indicating strength of structural relaxation/chain rigidity behavior and thermogravimetric analysis displayed increased thermal stability and conductivity (decreased interfacial resistance). We also measured temperature dependent dc electrical conductivity and dielectric relaxation spectroscopy gaining insights into percolation and dynamic interfacial layer. This study signified understanding of interactions and interfacial regions, key element to demystify the microscopic structure-property relationships.聚合物纳米复合材料(pnc)由于其形态和成分之间的定制界面而具有多功能性,在现代和未来的应用中具有重要意义。然而,采用更小尺寸纳米颗粒(客体)的“正向”工程聚合物(主体)复合材料提供所需的性能仍然具有挑战性,因为它们取决于纳米颗粒的聚集、尺寸、形状和负载(体积或重量)分数。本研究战略性地设计和开发了pnc,包括热塑性聚(2-乙烯基吡啶)(P2VP)聚合物矩阵,其中浸染了球形多面体低聚硅氧烷(N-POSS)纳米颗粒(直径~ 2-5 nm)和各向异性平面氮化石墨烯纳米带(GNR,条带宽度~ 5 - nm),与聚合物链的旋转半径Rg(或片段长度~ 1.5 nm)相当,并具有可比较的静电相互作用和吸引氢键的能量尺度。我们研究了与界面区域相关的静态和动态结构以及热物理性质,并将结果与较大的氧化石墨烯(GO,横向尺寸~ 100-200 nm)纳米片和二氧化硅(SiO2, ~ 25-50 nm)颗粒进行了比较。电子显微镜显示了纳米颗粒的分布,微拉曼光谱和原子力显微镜分别测定了晶格键、共轭长度和力学性能。差示扫描量热法提供了玻璃化转变温度Tg的测量值,其正位移为~ 10-18 °C,纳米颗粒加载表明结构松弛/链刚性行为的强度,热重分析显示热稳定性和导电性增加(界面阻力降低)。我们还测量了温度相关的直流电导率和介电弛豫光谱,从而深入了解渗透和动态界面层。这一研究对了解相互作用和界面区域是揭开微观结构-性质关系的关键因素。Composites Science and TechnologyEfficient degradation of amine cured epoxy resin via the cleavage of C-N bond by amphiphilic dodecylbenzenesulfonic acidChizhou Wang, Ning Zhang, Shaodi Wu, Weijie Wang, Peng Zhao, Shiyu Jia, Yongqin Qi, Xianglin Hou, Xiaojing Cui, Tiansheng Dengdoi:10.1016/j.compscitech.2024.110442 两亲性十二烷基苯磺酸裂解C-N键高效降解胺固化环氧树脂Amine-cured epoxy resin (EP) is often compounded with carbon fiber (CF) used for wind power blades due to its excellent performance. However, the insolubility and infusibility of service-life-expired carbon fiber reinforced epoxy resin (CFREP) hinder its sustainable recycling. We reported a new strategy for efficient degradation of EP and CFREP with 0.5 mol% amphiphilic dodecylbenzenesulfonic acid (DBSA) in aqueous system. It was found that the strong lipophilicity of DBSA accelerated its enrichment on EP surface, and further promoted the diffusion of DBSA and H2O to the resin bulk phase. As a result, the degradation ratio of the EP powder reached 100 % at 190 °C only in 10 h. The characterization of FT-IR and NMR proved that the degradation mechanism of EP was the selective cleavage of C-N bond catalyzed by H+. The resin degradation products (RDP) containing active hydrogen were used to prepare polyurethane (PU) with good mechanical properties. This method achieves complete recycling of waste CFREP in aqueous systems.胺固化环氧树脂(EP)由于其优异的性能,常与碳纤维(CF)复合用于风力发电叶片。然而,碳纤维增强环氧树脂(CFREP)的不溶性和可灌注性阻碍了其可持续回收利用。本文报道了用0.5 mol%两亲性十二烷基苯磺酸(DBSA)在水溶液中高效降解EP和CFREP的新策略。发现DBSA的强亲脂性加速了其在EP表面的富集,进一步促进了DBSA和H2O向树脂体相的扩散。结果表明,在190 ℃下,仅10 h, EP粉末的降解率就达到了100% %。FT-IR和NMR表征证明了EP的降解机制是h +催化C- n键的选择性裂解。采用含活性氢的树脂降解产物(RDP)制备了具有良好力学性能的聚氨酯(PU)。该方法实现了水系统中废弃CFREP的完全回收。来源:复合材料力学仿真Composites FEM

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