今日更新：Composite Structures 1 篇，Composites Part A: Applied Science and Manufacturing 2 篇，Composites Part B: Engineering 3 篇，Composites Science and Technology 1 篇Composite StructuresA non-uniform compound strip method for effective buckling analysis of stiffened structuresHao Yu, Pizhong Qiaodoi:10.1016/j.compstruct.2024.118529加筋结构有效屈曲分析的非均匀复合条法In this paper, a versatile compound strip method (CSM) with non-uniform spline functions is developed for buckling analysis of stiffened structures. The proposed method further extends the existing CSM by permitting the flexible modification of local knots to place the stiffeners along the strip arbitrarily. Besides, a reasonable knot arrangement can achieve an accurate solving procedure with improved convergence. The displacements of stiffeners are expressed compatibly by the fundamental parameters of skin according to the beam-plate model. Consequently, the reinforcement of stiffeners is naturally incorporated by adding the beam stiffness matrix to the corresponding strips. Based on the first-order shear deformation plate theory and non-uniform spline functions, the semi-analytical formulations of stiffened structures are established. The present method provides the possibility to achieve the local mesh refinement in the finite strip methods. The convergence and validation study is demonstrated through the comparisons with the results of the existing literature solution and finite element method. Finally, a more efficient and applicable CSM is proposed to analyze the buckling behaviors of stiffened structures.本文提出了一种具有非均匀样条函数的通用复合条法，用于加筋结构的屈曲分析。提出的方法进一步扩展了现有的CSM，允许对局部节进行灵活修改，以任意地沿带材放置加强筋。此外，合理的结排可以实现精确的求解过程，并提高收敛性。根据梁板模型，用蒙皮基本参数协调地表示加强筋的位移。因此，通过将梁刚度矩阵添加到相应的条带中，自然地结合了加强筋的加强。基于一阶剪切变形板理论和非均匀样条函数，建立了加筋结构的半解析表达式。该方法为在有限条法中实现局部网格细化提供了可能。通过与已有文献解和有限元法结果的比较，证明了该方法的收敛性和有效性。最后，提出了一种更有效、更适用于加劲结构屈曲行为分析的CSM方法。Composites Part A: Applied Science and ManufacturingHierarchical modification of bimodal grain structure in Al/Ti laminated composites for extraordinary strength-ductility synergyBiaohua Que, Liang Chen, Yuhui Zhao, Lihua Qian, Jun Lin, Cunsheng Zhang, Guoqun Zhaodoi:10.1016/j.compositesa.2024.108438Al/Ti层合复合材料中双峰晶粒结构的分层改性及其强度-延性协同作用Al/Ti laminates with altering Al grain sizes was fabricated via hot press sintering. Fine Al powders results in low sintering density and obvious cracks at Al/Ti interface. Large Al powders greatly increased the grain size, grain aspect ratio, LAGBs fraction, and recrystallization fraction of the Al layers. The texture heterogeneity is also significant, with rolling texture in Ti layer and random texture in Al layer. Ti5Si3 phase precipitated at Al/Ti interface, and it gradually partitioned Ti atoms from TiAl3 and hindered the formation of TiAl3. Moreover, numerous stacking faults, dislocation loops, dislocation pinning, and dislocation tangles were observed at Al/Ti interface, resulting in an increased back stress. Large Al grains contributes the highest bending strength of 734.8 MPa, tensile strength of 753.2 MPa, and fracture strain of 62 %. The effect of grain size on work hardening was attributed to the fraction of LAGBs, dislocation storage capacity and additional HDI strengthening.采用热压烧结技术制备了改变Al晶粒尺寸的Al/Ti层压板。Al粉末细，烧结密度低，Al/Ti界面裂纹明显。大尺寸Al粉末大大提高了Al层的晶粒尺寸、晶粒长径比、LAGBs分数和再结晶分数。织构的非均匀性也很明显，Ti层为滚动织构，Al层为随机织构。Ti5Si3相在Al/Ti界面析出，使Ti原子逐渐从TiAl3中分离出来，阻碍了TiAl3的形成。此外，在Al/Ti界面上观察到大量的层错、位错环、位错钉住和位错缠结，导致背应力增加。大Al晶粒的抗折强度最高，为734.8 MPa，抗拉强度为753.2 MPa，断裂应变为62 %。晶粒尺寸对加工硬化的影响主要归因于LAGBs的含量、位错储存容量和额外的HDI强化。Synergistic carbon nanotube ＋ carbon-coated iron nanoparticle polymer composites: Electrical, magnetic, and mechanical propertiesJassimran Arora, Tyler N. Tallmandoi:10.1016/j.compositesa.2024.108439协同碳纳米管+碳包覆铁纳米粒子聚合物复合材料:电、磁、机械性能Composite multifunctionality enabled by nanofiller modification has been widely explored in diverse applications. To date, work in this area has focused overwhelmingly on polymers modified with only a single type of nanofiller. Even studies that use more than one type of filler generally do so in order to achieve just a single type of multifunctionality—for example, modification with a combination of carbon nanotubes (CNTs) and graphene for higher electrical conductivity. Much less work has been done in the area of modifying polymers with multiple nanofiller types having dissimilar properties. To that end, we modify a representative polymer (epoxy) with a combination of multi-walled (MW)CNTs and carbon-coated iron nanoparticles (CCFeNPs). These phases give rise to combined electrical and magnetic properties in the MWCNT ＋ CCFeNP composite. DC and AC conductivity, permittivity, permeability, elastic modulus, and piezoresistive gauge factor were measured for varying relative concentrations of MWCNTs and CCFeNPs. Synergistic effects were observed, such as higher electrical conductivity and magnetic permeability in MWCNT ＋ CCFeNP composites. More specifically, composites containing 0.4 wt% MWCNT ＋ 0.1 wt% CCFeNP increased in DC conductivity by 0.5-0.6 S/m compared to 0.5 wt% MWCNT-only specimens. Furthermore, 0.1 wt% MWCNT ＋ 0.4 wt% CCFeNP composites showed a magnetic saturation increase of 1.66 × 10−4 emu/cm3 over 0.5 wt% CCFeNP-only composites.纳米填料改性带来的复合多功能性已在各种应用中得到广泛探索。迄今为止，该领域的研究工作绝大多数都集中在仅使用单一类型纳米填料改性的聚合物上。即使是使用一种以上填料的研究，一般也只是为了实现单一类型的多功能性--例如，使用碳纳米管（CNT）和石墨烯的组合进行改性，以获得更高的导电性。在聚合物改性领域，使用具有不同特性的多种纳米填料进行改性的工作要少得多。为此，我们使用多壁 (MW) CNT 和碳包覆铁纳米粒子 (CCFeNPs) 对具有代表性的聚合物（环氧树脂）进行了改性。这些相位在 MWCNT ＋ CCFeNP 复合材料中产生了综合的电气和磁性能。测量了不同相对浓度的 MWCNTs 和 CCFeNPs 的直流和交流电导率、介电常数、磁导率、弹性模量和压阻系数。观察到了协同效应，例如 MWCNT ＋ CCFeNP 复合材料具有更高的导电性和磁导率。更具体地说，与仅含 0.5 wt% MWCNT 的试样相比，含 0.4 wt% MWCNT ＋ 0.1 wt% CCFeNP 的复合材料的直流导电率提高了 0.5-0.6 S/m。此外，0.1 wt% MWCNT ＋ 0.4 wt% CCFeNP 复合材料与纯 0.5 wt% CCFeNP 复合材料相比，磁饱和度增加了 1.66 × 10-4 emu/cm3。Composites Part B: EngineeringDesigning density-graded cellular materials for tailored constitutive responseVijendra Gupta, Addis Kidanedoi:10.1016/j.compositesb.2024.111793设计密度梯度的细胞材料为量身定制的本构响应Cellular materials are known for their lightweight nature and remarkable energy absorption characteristics attributed to their cellular structure. This study focuses on the design aspect of cellular materials to achieve specific constitutive responses through density gradation. A three-parameter empirical constitutive model is employed to characterize the behavior of density-graded cellular materials, utilizing experimentally derived parameters for rigid polyurethane foam. The investigation reveals a highly nonlinear spatial variation of local strains that influence the mechanical behavior of density-graded materials. The study investigates the isolated effect of density gradients within these materials on their mechanical behavior and energy absorption. Comparative analyses demonstrate that density-graded materials outperform uniform-density counterparts, particularly at lower stress levels, with greater energy absorption enhancement observed in materials featuring steeper density gradients. Finally, the optimal variables controlling density variation are identified to achieve desired stress–strain responses. These findings contribute to the enhanced understanding and practical utilization of density-graded cellular materials in applications requiring tailored mechanical performance and energy absorption capabilities.蜂窝材料以其轻便的特性和由于其细胞结构而具有的显著的能量吸收特性而闻名。本研究的重点是设计方面的细胞材料，以实现特定的本构响应，通过密度梯度。采用三参数经验本构模型，利用实验导出的硬质聚氨酯泡沫材料参数来表征密度梯度蜂窝材料的行为。研究揭示了影响密度梯度材料力学行为的局部应变的高度非线性空间变化。该研究调查了这些材料中密度梯度对其力学行为和能量吸收的孤立影响。对比分析表明，密度梯度材料优于均匀密度材料，特别是在较低应力水平下，密度梯度较大的材料具有更大的能量吸收增强。最后，确定控制密度变化的最优变量，以获得理想的应力-应变响应。这些发现有助于在需要定制机械性能和能量吸收能力的应用中增强对密度梯度细胞材料的理解和实际利用。Vat Photopolymerization 3D Printing of Glass Microballoon-Reinforced TPMS Meta-structuresBrandon Huffman, Anil Singh, Behrad Koohbor, George Youssefdoi:10.1016/j.compositesb.2024.111799玻璃微球增强TPMS元结构的还原光聚合3D打印Advancements in additive manufacturing coincide with the influx of assiduous research in realizing complex structures using printable composite materials with tunable properties. In this research study, photocurable resins with a broad range of mechanical properties were hybridized with ceramic particles to engineer the overall mechanical response. The newly formulated printable resins comprised up to 20 wt.% glass microballoons, balancing the tunability of the composite properties and manufacturability by overcoming light-reinforcement challenges. The compressive and tensile bulk properties were first assessed using additively manufactured samples tested under quasi-static loading. Complementary digital image correlation (DIC) was used to resolve the strain fields, revealing insights about the mechanical behavior and failure modes as a function of reinforcement weight ratio. Despite the expected hyperelastic constitutive behavior and shared macromolecular composition, the neat and hybridized photocurable resins exhibited distinctive mechanical behavior, leading to the characterization of the dynamic properties as a function of temperature to ascertain the underpinnings of respective responses. Triply periodic minimal surface (TPMS) structures were also manufactured using the vat photopolymerization approach to demonstrate the utility of newly formulated printable composite resins. The printed structures were tested under compression at a quasi-static loading rate. The DIC-resolved strains revealed the underlying structural mechanics as a function of the material properties. This case study correlates the mechanics governing particulate-reinforced elastomers with the observed variations in strain development, stiffness, load-bearing capacity, and specific energy absorption for TPMS structures. Finite element analysis (FEA) based on hyperelastic potential and using the properties of the bulk resin closely matched the deformation patterns from the experimental DIC results. The outcomes of this research reveal the potential for tunable, 3D printed sports gear for impact mitigation in various biomechanical loading conditions.增材制造的进步与使用具有可调性能的可打印复合材料实现复杂结构的刻苦研究相吻合。在这项研究中，具有广泛机械性能的光固化树脂与陶瓷颗粒杂交，以设计整体机械响应。新配方的可打印树脂含有高达20wt .%的玻璃微球，通过克服光增强挑战，平衡了复合材料性能的可调性和可制造性。压缩和拉伸体积性能首先通过在准静态载荷下测试的增材制造样品进行评估。利用互补数字图像相关(DIC)解析应变场，揭示了钢筋重量比对力学行为和破坏模式的影响。尽管具有预期的超弹性本构行为和共同的大分子组成，但整齐和杂交光固化树脂表现出不同的力学行为，导致动态特性的表征作为温度的函数，以确定各自响应的基础。三周期最小表面(TPMS)结构也使用还原光聚合方法制造，以证明新配制的可打印复合树脂的实用性。在准静态加载速率下对打印结构进行了压缩测试。dic分解应变揭示了材料性能的基本结构力学特性。本案例研究将控制颗粒增强弹性体的力学与观察到的TPMS结构的应变发展、刚度、承载能力和比能吸收的变化联系起来。基于超弹性势的有限元分析(FEA)利用体树脂的特性与DIC实验结果的变形模式吻合较好。这项研究的结果揭示了可调的3D打印运动装备在各种生物力学载荷条件下减轻冲击的潜力。Electrochemical Evaluation of Fenitrothion Organophosphate Pesticide in Food Samples: Novel Tetra Trifluoromethyl Carboxamide Zinc (II) Macrocyclic Complex Composite with Multiwalled Carbon NanotubesMounesh, O. Nagaraja, Hareesh Nagarajappa, Sharanakumar T. M, Anup Pandith, Wahidah H. Al-Qahtani, Bhari Mallanna Nagarajadoi:10.1016/j.compositesb.2024.111808 多壁碳纳米管新型四乐三氟甲基羧酰胺锌(II)大环配合物复合材料的电化学评价This study presents the development of a groundbreaking electrochemical sensor for detecting fenitrothion (FNT) using a multi-walled carbon nanotubes (MWCNTs) and a newly synthesized zinc (II) tetra trifluoromethyl carboxamide phthalocyanine (ZnTFMPCAPc). The ZnTFMPCAPc was synthesized concluding a two-step mechanical and magnetic stirring method, and the ensuing ZnTFMPCAPc@MWCNTs underwent comprehensive characterization employing X-ray diffraction (XRD), Ultraviolet visible spectroscopy (UV-Vis), mass spectrum, Fourier transform infrared spectroscopy (FT-IR), Thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Mass, Raman spectra, Transmission Electron Microscopy (TEM) and scanning electron microscope (SEM). Cyclic voltammetry (CV) analysis demonstrated a remarkable seven-fold improvement in electrochemical signals with ZnTFMPCAPc@MWCNTs on modified glassy carbon electrode (GCE) compared to a bare and modified GCE. The correlation between peak current and FNT concentration (in the range of 10–310 μmol) was established. The estimated limits of detection (LOD) and quantification (LOQ) were determined to be 1.358 nmol and 4.075 nmol respectively. The ZnTFMPCAPc@MWCNTs/GCE sensor was successfully evaluated by quantifying FNT in tomatoes, grapes, paddy grains, and potato extracts, resulting in satisfactory results. Detecting fenitrothion is crucial due to its widespread use as a pesticide, which can result in environmental contamination and pose health risks. Regular monitoring is essential for protecting food and water supplies, preserving ecosystems, and ensuring compliance with regulations to prevent long-term environmental damage.本研究采用多壁碳纳米管(MWCNTs)和新合成的锌(II)四氟甲基羧酰胺酞菁(ZnTFMPCAPc)，开发了一种突破性的检测非硝基离子(FNT)的电化学传感器。采用机械搅拌和磁搅拌两步法制备了ZnTFMPCAPc，并利用x射线衍射(XRD)、紫外可见光谱(UV-Vis)、质谱、傅里叶红外光谱(FT-IR)、热重分析(TGA)、x射线光电子能谱(XPS)、质量、拉曼光谱、透射电子显微镜(TEM)和扫描电子显微镜(SEM)对所得ZnTFMPCAPc@MWCNTs进行了综合表征。循环伏安法(CV)分析表明，ZnTFMPCAPc@MWCNTs修饰的玻碳电极(GCE)的电化学信号比未修饰和修饰的玻碳电极(GCE)显著提高了7倍。建立了峰电流与FNT浓度(10 ~ 310 μmol)之间的相关性。检出限(LOD)和定量限(LOQ)分别为1.358 nmol和4.075 nmol。ZnTFMPCAPc@MWCNTs/GCE传感器通过量化番茄、葡萄、稻谷和马铃薯提取物中的FNT，成功地进行了评估，结果令人满意。检测杀虫剂是至关重要的，因为它作为一种农药被广泛使用，可能导致环境污染并构成健康风险。定期监测对于保护粮食和水供应、保护生态系统以及确保遵守法规以防止长期环境破坏至关重要。Composites Science and TechnologyMesoscale mechanism of damage in fracture process zone of CFRP laminates simulated with triaxial stress state-dependent constitutive equation of matrix resinSota Oshima, Yuji Seryo, Masao Kimura, Masaki Hojodoi:10.1016/j.compscitech.2024.110837 基于三轴应力状态相关的基体树脂本构方程模拟CFRP复合材料断裂过程区的细观损伤机制The three-dimensional failure process experimentally observed by synchrotron radiation X-ray computed tomography (SR X-CT) regarding the influence of the interfiber distance is discussed on the basis of the results of numerical experiments. Triaxial stress states in the fracture process zone of carbon fiber reinforced polymers were analyzed on the mesoscale under mode I and mixed-mode (mode I + II) loading. Yield and damage models depending on stress triaxiality were used to accurately simulate three-dimensional stress states in the damage zone around the crack tip. Owing to the heterogeneity of composites, deviatoric stress is prominent in the thin resin region where the interfiber distance is small under mode I loading. On the other hand, matrix resin is triaxially stressed in the middle point between carbon fibers in the thick resin region where the interfiber distance is large. Under mode II loading, the shapes of fiber/matrix debonding depended on the interfiber distance. Areas with stress concentration were found owing to a large debonding area in the thick resin region resulting in a matrix cracking-prone stress state. These findings explain the damage and failure processes well observed by SR X-CT and provide a fundamental understanding of the damage mechanism at a mesoscale.在数值实验结果的基础上，讨论了同步辐射x射线计算机断层扫描(SR X-CT)实验观测到的光纤三维破坏过程中光纤间距离的影响。在细观尺度上分析了碳纤维增强聚合物断裂过程区在I模式和混合模式(I + II模式)加载下的三轴应力状态。采用基于应力三轴性的屈服和损伤模型，精确模拟了裂纹尖端周围损伤区的三维应力状态。由于复合材料的非均质性，在I型加载下，纤维间距较小的薄树脂区偏应力突出。另一方面，在纤维间距离较大的厚树脂区，在碳纤维之间的中点处，基体树脂受到三轴应力。在II型加载下，纤维/基体剥离的形状与纤维间距离有关。由于厚树脂区存在较大的脱粘区，导致基体易开裂应力状态，从而形成应力集中区域。这些发现很好地解释了SR X-CT观察到的损伤和破坏过程，并提供了中尺度损伤机制的基本理解。来源：复合材料力学仿真Composites FEM
