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【新文速递】2024年11月16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 2 篇,Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Minimum energy combined and separated bounds on elastic constants of transversely-isotropic composites

Duc-Chinh Pham

doi:10.1016/j.ijsolstr.2024.113134

横向各向同性复合材料弹性常数的最小能量组合界和分离界

The considered linearly-elastic transversely-isotropic composite (TIC) is composed of n isotropic, or more generally, transversely-isotropic components sharing the materials’ common symmetry axis with that of the macroscopic material. Using the basic minimum energy and complementary energy principles with certain free-parameter-dependent mixed-longitudinal-transverse-mode strain and stress trial fields, various combination bounds involving some sets of the macroscopic (effective) mixed-mode elastic constants of the composite, which are inter-connected via the constitutive relations, have been established. Choosing the appropriate parameter values of/or optimizing over the free parameters in those inequalities, the separated bounds on the major effective mixed-transverse-longitudinal-mode elastic constants, including the transverse bulk modulus K_eff, the longitudinal Young modulus E_eff, and the longitudinal Poisson’s ratio ν_eff, are derived, beside the classical arithmetic and harmonic average bounds on the pure-mode ones - the transverse shear (μ_eff) and longitudinal shear (μ`_eff) moduli. The separated bounds on 4 remaining effective mixed-mode elastic constants are also obtained. The illustrative numerical comparisons of the bounds, in the two component case, with those for the special subclass of unidirectional transversely-isotropic composites (UTIC), having the unidirectional cylindrical boundaries between the component materials parallel to their symmetry axis, and the exact coated-cylinder assemblage and laminate models are presented. The extreme models cover substantial parts between the bounds for TIC; however the laminate models lie outside the bounds for the subclass UTIC.

考虑的线性弹性横向各向同性复合材料(TIC)由n个各向同性或更一般地,横向各向同性组件组成,这些组件与宏观材料的对称轴共享材料的对称性。 利用基本的能量最小化和补充能量原理,以及与某些自由参数相关的混合纵向-横向模式应变和应力试探场,建立了涉及复合材料宏观(有效)混合模式弹性常数的一些集 合的组合界限,这些常数通过本构关系相互关联。 选择这些不等式中的适当参数值或对自由参数进行优化,除了经典的算术和调和平均纯模式界限(横向剪切模量μ_eff和纵向剪切模量μ`_eff)之外,还得出了分离的纯模式界限,包括横向体模量K_eff、纵向杨氏模量E_eff和纵向泊松比ν_eff。还获得了剩余4个有效混合模量边界的分离解。在两组元情况下,将这些边界与具有平行于对称轴的组元材料的单向圆柱形边界之间的特殊子类各向同性复合材料(UTIC)的边界、精确的涂层圆柱体组合模型和层合模型进行了说明性的数值比较。极端模型覆盖了TIC边界的大部分区域,但层合模型则位于子类UTIC的边界之外。


Journal of the Mechanics and Physics of Solids

Unraveling the Molecular Mechanisms of Membrane Rupture: Insights from All-Atom Simulations and Theoretical Modeling

Panpan Zhu, Ji Lin, Yimou Fu, Chun Shen, Haofei Zhou, Shaoxing Qu, Huajian Gao

doi:10.1016/j.jmps.2024.105958

揭开膜破裂的分子机制:来自全原子模拟和理论建模的见解

Cell membrane rupture occurs universally and is long thought to be the terminal event of cell death; however, there is an inadequate understanding of the microscopic mechanisms of membrane rupture at the molecular level. In this study, we investigated the rupture mechanism of two model membranes, 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and cholesterol bilayer membranes, under surface tension by all-atom molecular simulations and theoretical modeling. Under surface tension, the tail chains of POPC molecules become disordered, leading to ductile membrane deformation, while cholesterol membranes display limited deformation before rupture. We analyzed the orientation of tail chains and the internal stresses within the membranes, revealing that the mutual attraction among different tail chains and the resulting stress peak in the tail region of the membrane play substantial roles in the membrane rupture process. Based on these physical insights, we proposed a theoretical model that incorporates an internal variable of tail chain orientation to capture the variations in strain and orientation of different membrane components under varying surface tensions. The critical rupture threshold predicted by our theoretical model aligns well with the simulation results, demonstrating a brittle to ductile transition for membranes with different cholesterol contents. Our study unravels the impact of tail chain orientation and internal stress on membrane mechanics, which deepens the understanding of the microscale mechanisms underlying membrane rupture.

细胞膜破裂是普遍存在的,长期以来被认为是细胞死亡的终末事件;然而,在分子水平上对膜破裂的微观机制了解不足。本研究采用全原子分子模拟和理论建模的方法,研究了1-棕榈酰-2-油酰-磷脂酰胆碱(POPC)和胆固醇双层膜在表面张力作用下的破裂机理。在表面张力作用下,POPC分子尾链变得无序,导致韧性膜变形,而胆固醇膜在破裂前表现为有限变形。我们分析了尾链的取向和膜内的内应力,揭示了不同尾链之间的相互吸引以及在膜尾部区域产生的应力峰值在膜破裂过程中起着重要作用。基于这些物理见解,我们提出了一个理论模型,该模型包含尾链取向的内部变量,以捕捉不同表面张力下不同膜组分的应变和取向变化。我们的理论模型预测的临界破裂阈值与模拟结果很好地吻合,表明具有不同胆固醇含量的膜具有脆性到延性的转变。我们的研究揭示了尾链取向和内应力对膜力学的影响,加深了对膜破裂微观机制的理解。


Mechanics of electroadhesion of polyelectrolyte hydrogel heterojunctions enabled by ionic double layers

Zheyu Dong, Zhi Sheng, Zihang Shen, Shaoxing Qu, Zheng Jia

doi:10.1016/j.jmps.2024.105960

离子双层驱动的聚电解质水凝胶异质结电粘附力学

In recent years, soft materials with reversible adhesion have come to the fore as a promising avenue of research. Compared to other reversible adhesion methods, electroadhesion enabled by the formation of ionic double layer (IDL) has been widely used due to its simplicity, low energy consumption, fast response, and reversibility. Despite the extensive experimental studies and qualitative mechanistic explanations, there remains a dearth of theoretical studies on this topic, particularly regarding the development of theoretical mechanics models. Our study aims to address this gap by establishing a mechanics model of IDL-enabled electroadhesion between soft materials. We specifically focus on modeling the low-voltage electroadhesion of heterojunctions between two polyelectrolyte hydrogels. The model decomposes the electroadhesion formation into two successive physical processes. First, under appropriate bias conditions, the applied voltage drives the mobile ions in each polyelectrolyte hydrogel to migrate toward the electrode, resulting in the formation of an IDL at the heterojunction interface and the generation of a potent built-in electric field inside the IDL. Second, driven by the strong built-in electric field of IDL, the dangling charged chains of the two polyelectrolyte hydrogels begin to cross the heterojunction interface and penetrate into the opposite hydrogel matrix to form ionic bonds with the oppositely-charged chains, resulting in a bridging network that sutures the interface. As a result, the electrostatic interactions inside the IDL as well as the bridging network across the interface leads to the electroadhesion of polyelectrolyte hydrogel heterojunctions. The modeling results show that the IDL thickness, the IDL electric field density, and the electroadhesion strength increase with the applied voltage. We also experimentally conduct the electroadhesion tests, and the measurements of electroadhesion strength quantitatively match the modeling results well. For the first time, we reveal the underlying mechanism of IDL-driven electroadhesion by establishing a theoretical mechanics model. We anticipate that our mechanics model can shed light on the design, optimization, and control of the electroadhesion of soft-material heterojunctions.

近年来,具有可逆性粘附的软质材料作为一种很有前途的研究方向而崭露头角。与其他可逆粘附方法相比,离子双层电粘附(IDL)具有简单、低能耗、响应快、可逆性等优点,得到了广泛的应用。尽管有大量的实验研究和定性的力学解释,但关于这一主题的理论研究仍然缺乏,特别是关于理论力学模型的发展。我们的研究旨在通过建立软材料之间idl驱动的电粘附的力学模型来解决这一差距。我们特别专注于模拟两种聚电解质水凝胶之间异质结的低压电粘附。该模型将电粘附的形成分解为两个连续的物理过程。首先,在适当的偏置条件下,施加的电压驱动每个聚电解质水凝胶中的可移动离子向电极迁移,导致在异质结界面处形成IDL,并在IDL内部产生强大的内置电场。其次,在IDL强大的内置电场的驱动下,两种聚电解质水凝胶的悬空带电链开始穿过异质结界面,并渗透到相反的水凝胶基质中,与相反的带电链形成离子键,形成桥接网络,将界面连接起来。因此,IDL内部的静电相互作用以及界面上的桥接网络导致了聚电解质水凝胶异质结的电粘附。模拟结果表明,随着施加电压的增加,IDL厚度、IDL电场密度和电粘附强度均增加。我们还进行了电粘附实验,电粘附强度的测量结果与模型结果吻合较好。我们首次通过建立理论力学模型揭示了idl驱动电粘附的潜在机制。我们期望我们的力学模型可以为软材料异质结的电粘附设计、优化和控制提供启示。


Thin-Walled Structures

Effect of fractal dimension on mechanical behaviour and energy absorption of Menger sponge-inspired fractal structures

Madhusha Bogahawaththa, Damith Mohotti, Paul J. Hazell, Hongxu Wang, Kasun Wijesooriya, Chi King Lee

doi:10.1016/j.tws.2024.112704

分形维数对Menger海绵状分形结构力学性能和吸能的影响

The Fractal Dimension (FD) of Menger Fractal Cubes (MFCs) defines their intricate geometry, making them ideal for lightweight structural applications. However, the effect of FD on their structural behaviour is largely unexplored. This study examines AlSi7Mg MFC geometries formed through a recursive process, with densities ranging from 40 to 1958 kg/m³, corresponding to FDs ranging from 2.35 to 2.73. Compression tests and simulations revealed that higher fractal orders increased densification displacement, achieving up to 80% compressibility, with multi-level extended plateau regions indicating enhanced energy absorption. The fourth-order MFC with an FD of 2.35 and a density of 40 kg/m³ showed a specific energy absorption (SEA) of 6 J/g, demonstrating its potential for weight-efficient, energy-absorbing structures. The outcomes of this study indicate that total energy absorbed increases with an increasing FD, while crush efficiency improves as FD decreases showing better crashworthiness. Moreover, the structures exhibited unique force-displacement responses tailored to their FD. These findings offer valuable insights into optimising thin-walled fractal structures for various engineering applications by adjusting the FD to fine-tune relative density and enhance mechanical performance.

门格尔分形立方体(mfc)的分形维数(FD)定义了它们复杂的几何形状,使它们成为轻量化结构应用的理想选择。然而,FD对其结构行为的影响在很大程度上尚未被探索。本研究考察了通过递归过程形成的AlSi7Mg MFC几何形状,其密度范围为40至1958 kg/m³,对应的fd范围为2.35至2.73。压缩试验和模拟表明,更高的分形阶数增加了致密化位移,可达到80%的压缩率,多层次扩展的高原区域表明能量吸收增强。四阶MFC的FD为2.35,密度为40 kg/m³,比能吸收(SEA)为6 J/g,显示了其作为减重吸能结构的潜力。研究结果表明,总能量吸收随FD的增加而增加,粉碎效率随FD的减小而提高,具有较好的耐撞性。此外,结构表现出与其FD相适应的独特的力-位移响应。这些发现为优化各种工程应用的薄壁分形结构提供了有价值的见解,通过调整FD来微调相对密度并提高机械性能。




来源:复合材料力学仿真Composites FEM
ACTMechanicalInspireDeform复合材料ADS电场理论材料控制试验
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首次发布时间:2024-11-21
最近编辑:8天前
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【新文速递】2024年11月11日复合材料SCI期刊最新文章

今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇Composite StructuresElectrical energy and overpressure characterization of aeronautical fasteners submitted to a lightning current waveformRafael Sousa Martins, Amélie Jarnac, Clément Zaepffel, Philippe Lalandedoi:10.1016/j.compstruct.2024.118700雷电电流波形下航空紧固件的电能和超压特性Understanding and controlling sparking in fasteners and jointed structures is crucial for flight safety, particularly in fuel tanks. This study investigates the relationship between dissipated electrical energy and pressure buildup within fastener cavities during lightning strikes. Experiments were performed on fasteners installed in aluminum and Carbon Fiber Reinforced Polymer (CFRP) samples, with lightning current waveforms ranging from 1 kA to 10 kA. A sensitivity analysis evaluated the influence of key parameters, such as current peak, clearance fit, sample material, polarity, and fastener coating on pressure rise and energy dissipation. Electrical energy up to 80J and pressure levels reaching 600 bar– unprecedented compared to prior studies – were observed. The pressure-energy relationship showed an approximately linear trend, while pressure exhibited a non-linear dependence on clearance fit. Fastener coating and sample material were found to significantly influence the results, with pressure variations reaching up to a factor of 10 in some cases.了解和控制紧固件和连接结构中的火花对飞行安全至关重要,特别是在油箱中。本研究探讨了雷击时紧固件腔内耗散的电能和压力之间的关系。对安装在铝和碳纤维增强聚合物(CFRP)样品中的紧固件进行了实验,雷电电流波形范围为1 kA至10 kA。灵敏度分析评估了关键参数,如电流峰值、间隙配合、样品材料、极性和紧固件涂层对压力上升和能量耗散的影响。观察到高达80J的电能和达到600 bar的压力水平-与先前的研究相比是前所未有的。压力-能量关系呈现近似线性趋势,而压力与间隙拟合呈非线性关系。发现紧固件涂层和样品材料对结果有显著影响,在某些情况下压力变化可达10倍。Inverse design method of deployable cylindrical composite shells for solar sail structureZheng Zhang, Diyong Huang, Baisong Pan, Huping Zhou, Jingya Ma, Min Sun, Shouzhi Ren, Guang Zhangdoi:10.1016/j.compstruct.2024.118698太阳帆结构可展开圆柱复合壳的反设计方法The deployable cylindrical composite shell (DCCS) applied in the solar sail structure requires suitable geometric parameters to have high storage capacity and large sunlight area. However, it is difficult to obtain the suitable geometric parameters of DCCS. An inverse design method combining the advantages of radial basis function artificial neural network (RBFANN) and multi-island genetic algorithm (MIGA) is proposed to obtain the geometric parameters of DCCS in this paper. RBFANN has the ability of self-learning and nonlinear problem solving, MIGA has the ability of global optimization. The specimens of DCCS were manufactured based on the obtained geometric parameters. The coiling radius, driving characteristics of specimens were studied by experiment and finite element simulation, and the numerical results are in good agreement with the experimental results, which verify the effectiveness of the inverse design method. The inverse design method proposed in this paper can effectively obtain the geometric parameters of DCCS, which also can guide the design of solar sail structure.应用于太阳帆结构的可展开圆柱形复合材料壳体(DCCS)需要合适的几何参数来保证高存储容量和大的日照面积。然而,DCCS的几何参数很难确定。结合径向基函数人工神经网络(RBFANN)和多岛遗传算法(MIGA)的优点,提出了一种求解DCCS几何参数的反设计方法。RBFANN具有自学习能力和非线性问题求解能力,MIGA具有全局优化能力。根据得到的几何参数制作DCCS试件。通过实验和有限元模拟对试件的卷取半径、驱动特性进行了研究,数值结果与实验结果吻合较好,验证了反设计方法的有效性。本文提出的逆设计方法可以有效地获得DCCS的几何参数,也可以指导太阳帆结构的设计。Finite element submodeling technique-based fatigue analysis and reliability modeling of wind turbine blade trailing edgeZheng Liu, Jinlong Liang, Zhenfeng He, Xin Liu, Haodong Liu, Zhenjiang Shaodoi:10.1016/j.compstruct.2024.118699基于有限元子建模技术的风力机叶片尾缘疲劳分析与可靠性建模Wind turbine blades play a critical role in wind turbine systems, with the trailing edge bearing significant mechanical loads. During operational cycles, the adhesively bonded composite trailing edge may fracture, delaminate, or buckle, posing a safety risk for wind turbine systems. While finite element simulation is commonly used to evaluate blade fatigue performance due to the challenges associated with full-scale structural tests in terms of costs and time, current methodologies mainly focus on the overall fatigue characteristics of blades, neglecting specialized analyses. A finite element submodeling approach is presented here to address this research gap by analyzing wind turbine blade trailing edges for fatigue and reliability. Specifically, a finite element submodelingmethodis proposedtoanalyzelocal fatiguefailuresof wind turbine blades. This approach is validated through fatigue testing on conventional composite bonded specimens. Subsequently, failure analyses and life predictions are conducted on the trailing edges to investigate their fatigue behavior, followed by an exploration of the impact of submodeling techniques on the analysis results. Furthermore, considering material and dimensional uncertainties, a fatigue reliability model for trailing edges is developed. The results demonstrate that this approach effectively overcomes the limitations of overall blade finite element analysis by enabling localized fatigue analysis of the trailing edge, providing valuable insights for improving wind turbine blade design optimization.风力涡轮机叶片在风力涡轮机系统中起着至关重要的作用,其后缘承受着巨大的机械载荷。在运行周期中,粘接复合材料后缘可能会断裂、分层或弯曲,对风力涡轮机系统构成安全风险。由于在成本和时间方面与全尺寸结构测试相关的挑战,有限元模拟通常用于评估叶片的疲劳性能,但目前的方法主要集中在叶片的整体疲劳特性上,而忽略了专业分析。本文提出了一种有限元子建模方法,通过分析风力机叶片尾缘的疲劳和可靠性来解决这一研究空白。具体地说,提出了一种分析风力发电机叶片局部疲劳失效的有限元子建模方法。通过常规复合材料粘结试件的疲劳试验验证了该方法的有效性。随后,对尾缘进行失效分析和寿命预测,以研究其疲劳行为,然后探索子建模技术对分析结果的影响。此外,考虑材料和尺寸的不确定性,建立了尾缘的疲劳可靠性模型。结果表明,该方法有效克服了整体叶片有限元分析的局限性,实现了尾缘局部疲劳分析,为改进风力机叶片设计优化提供了有价值的见解。Composites Part A: Applied Science and ManufacturingEffects of selective distribution of poly(methyl methacrylate)-grafted graphene oxide on the phase behavior and conductivity of poly(methyl methacrylate)/poly(vinyl acetate) blendsXiaofeng Yu, Zheng Xu, Yaobin Lu, Li Yang, Shihao Sun, Miao Du, Min Zuo, Qiang Zhengdoi:10.1016/j.compositesa.2024.108563 聚甲基丙烯酸甲酯接枝氧化石墨烯的选择性分布对聚甲基丙烯酸甲酯/聚醋酸乙烯共混物相行为和电导率的影响The effect of selective distribution of two kinds of poly (methyl methacrylate)-grafted graphene oxide (PMMA-g-GO) nanosheets (NSs) on the phase behavior and conductivity of PMMA/poly (vinyl acetate) (PVAc) blends is investigated. The grafting density and length of two modified GO NSs are different, resulting in their thermodynamic equilibrium location in the blend matrix, but their initial locations are both in the PVAc-rich phase with low viscosity. The PMMA-g-GO(6 k) NSs with the sparse mushroom-like grafted PMMA chains gradually migrate to the interface of blend matrix and aggregate to form the conductive network, resulting in the suppression of domain coarsening and long-term maintenance of co-continuous morphology. The grafted chains on the surface of PMMA-g-GO(58 k) NSs exhibit the screened wet brush and the PMMA matrix chains can penetrate with the grafted chains, resulting in the location in the PMMA-rich phase. Two modified GO NSs filled PMMA/PVAc nanocomposites can occur the conductive percolation and such activation energies are higher than those of flow for PMMA and PVAc, indicating that the interactions between modified GO and polymer components may restrict the aggregation of conductive modified GO NSs at the interface or in the PMMA-rich phase.研究了两种聚甲基丙烯酸甲酯接枝氧化石墨烯(PMMA-g- go)纳米片(NSs)的选择性分布对PMMA/聚醋酸乙烯酯(PVAc)共混物相行为和电导率的影响。两种改性的氧化石墨烯纳米粒子的接枝密度和长度不同,导致它们在共混基体中的热力学平衡位置不同,但它们的初始位置都在低粘度的富pvac相中。具有稀疏蘑菇状接枝PMMA链的PMMA-g- go(6 k) NSs逐渐迁移到共混基体和聚团界面形成导电网络,从而抑制畴粗化,长期维持共连续形态。PMMA-g- go(58 k) NSs表面的接枝链呈现出筛选过的湿刷状,PMMA基体链可以穿透接枝链,从而定位在富PMMA相中。填充PMMA/PVAc纳米复合材料的两种改性氧化石墨烯纳米粒子均可发生导电渗透,且其活化能均高于PMMA和PVAc的流动活化能,说明改性氧化石墨烯与聚合物组分之间的相互作用可能限制了导电改性氧化石墨烯纳米粒子在界面处或富PMMA相的聚集。Interface engineering of MXene towards highly fire-safe epoxy resin with enhanced thermal conductivityChuan Liu, Shu-Gen Wu, Jie-Hao He, Xin Li, Zhen Qin, Dong-Yi He, Yan-Fang Xiao, Yi Wang, Yu-Zhong Wang, Li Chendoi:10.1016/j.compositesa.2024.108585MXene面向高防火性增强导热环氧树脂的界面工程The integration of superior flame retardancy and enhanced thermal conductivity of epoxy resins (EP) is highly desirable for practical applications. Herein, novel organophosphorus-decorated MXene hybrid flame retardant (PMXene) was prepared by the interface engineering between melamine diphenylphosphinate (MDP) and two-dimensional titanium carbide (MXene). With the loading of 6.0 wt% PMXene, the EP/6.0PMXene material achieved a V-0 rating during the UL 94 testing besides the high limiting oxygen index (35.2 %). Cone calorimetric results revealed that the peak of heat release, peak of smoke release rate and smoke factor values of EP/6.0PMXene were reduced by 36.6 %, 27.6 % and 48.7 %, respectively, in comparison with those of pristine EP. Besides, the PMXene hybrid enhanced the thermal conductivity of EP to 0.38 W/m·K, a 52.6 % improvement over pristine EP. Thus, this work provides a novel strategy for fabricating thermosetting materials with high fire-safety and enhanced thermal conductivity.环氧树脂(EP)优异的阻燃性和增强的导热性在实际应用中是非常理想的。通过三聚氰胺二苯膦酸盐(MDP)与二维碳化钛(MXene)的界面工程,制备了新型有机磷修饰MXene杂化阻燃剂(PMXene)。在6.0 wt% PMXene的负载下,EP/6.0PMXene材料在UL 94测试中达到了V-0等级,并且具有高极限氧指数(35.2 %)。锥形量热结果表明,EP/6.0PMXene的放热峰、排烟率峰和排烟因子值分别比原始EP降低36.6 %、27.6 %和48.7 %。此外,PMXene混合材料将EP的导热系数提高到0.38 W/m·K,比原始EP提高了52.6% %。因此,这项工作为制造具有高防火安全性和增强导热性的热固性材料提供了一种新的策略。Composites Part B: EngineeringDesigning High-Performance Green Tire Treads by Reinforcing the Styrene-Butadiene Rubber/Silica Interface with Chain DifunctionalizationYihui Xu, Yudong Liu, Yangyang Gao, Ling Liu, Liqun Zhangdoi:10.1016/j.compositesb.2024.111887 利用链双官能化强化丁苯橡胶/二氧化硅界面设计高性能绿色轮胎胎面For green tires, monofunctionalization of rubber has been extensively studied to enhance the interface between rubber and silica. However, the effect of chain difunctionalization has not been reported. In this work, the difunctionalized styrene-butadiene rubber (SBR-DF) was first prepared by grafting small molecules with different functional groups (3-mercaptopropionic acid, 3-mercaptoethanol, and mercaptosilane) to end-group functionalized SBR through thiol-ene click reaction. Then, the molecular dynamics simulation was adopted to calculate the interaction energy between SBR-DF and silica. The results showed that the chain difunctionalization can significantly increase the interfacial interaction energy between them, which was further validated by using RPA and SEM. Moreover, the introduced siloxane groups in the rubber chain can greatly improve the interfacial interaction energy by more than 20%, which can achieve the uniform dispersion of silica. As a result, the SBR-DF/Silica composites showed the excellent dynamic mechanical properties, such as high wet slip resistance (21% increase), low rolling resistance (23% reduction) and high wear resistance (20% reduction). As a result, the energy consumption of SBR-DF/Silica composites was reduced, which endowed green tires with excellent safety. In summary, this work provides a new and effective strategy for manufacturing the energy-saving, green and safe design of “green tires”.对于绿色轮胎,人们广泛研究了橡胶的单功能化,以增强橡胶与二氧化硅之间的界面。然而,链双官能化的影响尚未见报道。本文首先通过巯基咔嗒反应将具有不同官能团的小分子(3-巯基丙酸、3-巯基乙醇和巯基硅烷)接枝到端基官能团化的SBR上,制备了双官能团化丁苯橡胶(SBR- df)。然后,采用分子动力学模拟方法计算SBR-DF与二氧化硅的相互作用能。结果表明,链的双官能化可以显著提高它们之间的界面相互作用能,并通过RPA和SEM进一步验证了这一点。此外,在橡胶链中引入硅氧烷基团,可大大提高界面相互作用能20%以上,可实现二氧化硅的均匀分散。结果表明,SBR-DF/Silica复合材料具有优异的动态力学性能,如高湿滑性能(提高21%)、低滚动性能(降低23%)和高耐磨性(降低20%)。因此,降低了SBR-DF/Silica复合材料的能耗,使绿色轮胎具有优异的安全性。本研究为实现节能、绿色、安全的“绿色轮胎”设计提供了新的有效策略。Composites Science and TechnologyDual covalent bond induced high thermally conductive polyimide composite films based on CNT@CN complex fillerFan Wang, Xiaodi Dong, Guangyi Liu, Jing-Hui Gao, Xu Wang, Jun-Wei Zhadoi:10.1016/j.compscitech.2024.110963 基于CNT@CN复合填料的双共价键诱导高导热聚酰亚胺复合薄膜Polyimide (PI) possesses excellent high-temperature resistance, insulation properties, and mechanical properties, making it widely used as a flexible printed circuit board substrate and high-temperature electrical insulation material. However, the irregular arrangement of PI molecules results in a relatively low thermal conductivity. This work utilizes the active groups on the surface of carboxylated multi-walled carbon nanotubes (MWCNTs) and carbon nitride nanosheets (CNNS) to obtain CNTs@CN complex fillers containing covalent bonds. The thermal conductivity of CNTs@CN/PI with double covalent bonds can be up to 6.63 W∙m-1∙K-1. The covalent bonds between fillers and fillers as well as between fillers and the matrix provide efficient and continuous pathways for phonon transmission. Additionally, finite element analysis further reveals the heat transfer mechanism of the CNTs@CN/PI composite film. Therefore, this will provide a feasible solution to enhance the thermal conductivity of PI, making it more promising for applications in electronic devices.聚酰亚胺(PI)具有优异的耐高温性能、绝缘性能和机械性能,广泛用作柔性印刷电路板基板和高温电绝缘材料。然而,PI分子的不规则排列导致其导热系数相对较低。本研究利用羧化多壁碳纳米管(MWCNTs)和氮化碳纳米片(CNNS)表面的活性基团获得含有共价键的CNTs@CN复合填料。具有双共价键的CNTs@CN/PI的导热系数可达6.63 W∙m-1∙K-1。填料与填料之间以及填料与基体之间的共价键为声子传输提供了高效、连续的途径。此外,通过有限元分析进一步揭示了CNTs@CN/PI复合膜的传热机理。因此,这将为提高PI的导热性提供一种可行的解决方案,使其在电子器件中的应用更具前景。来源:复合材料力学仿真Composites FEM

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