【新文速递】2024年10月11日固体力学SCI期刊最新文章

今日更新：Composite Structures 9 篇，Composites Part A: Applied Science and Manufacturing 7 篇，Composites Part B: Engineering 2 篇，Composites Science and Technology 8 篇Composite StructuresTunable mechanical properties of the 3D anticircular-curve transversal-isotropic auxetic structureGuo-Feng Li, Hai-Tao Liudoi:10.1016/j.compstruct.2024.118634三维反圆曲线横观各向同性结构的力学性能可调This work studies a three-dimensional anticircular-curve transversal-isotropic auxetic structure (3D-ATAS) with tunable Poisson’s ratio (υ) and tunable Young’s modulus (E) on the basis of hexagonal symmetry in the transverse plane using the anti-deformation method by the design of inclined rods as circular-curve rods in the opposite direction of the deformation (under compressive loading). By using the energy method, expressions of υ and E of 3D-ATAS are acquired, and based on the periodic boundary conditions, υ and E of 3D-ATAS are parametrically researched through numerical simulation and uniaxial compression experiments. The effects of anticircular-curve rod thickness t, anticircular-curve rod width b, and anticircular-curve cross-section angle θ to υ and E of 3D-ATAS are investigated. The tunable ranges of υ and E of 3D-ATAS are predicted, and the wide range of E is attained. Compared with the 3D circular-curve transversal-isotropic auxetic structure, E of 3D-ATAS is significantly enhanced in different directions, and the maximum enhanced up to 10 times. In the same way, both υ and E of 3D-ATAS are transversal-isotropic.本文采用抗变形方法，将斜杆设计成与变形方向相反的圆曲线杆（在压缩载荷下），研究了一种具有泊松比（υ）和杨氏模量(E)可调的三维反圆曲线横向各向同性结构（3D-ATAS）。利用能量法获得了3D-ATAS的υ和E的表达式，并基于周期边界条件，通过数值模拟和单轴压缩实验对3D-ATAS的υ和E进行了参数化研究。研究了反圆曲线杆厚t、反圆曲线杆宽b和反圆曲线截面角θ对3D-ATAS的影响。预测了3D-ATAS的可调范围υ和E，得到了较宽的E范围。与三维圆-曲线横向各向同性结构相比，三维atas的E在不同方向上均有显著增强，最大增强幅度可达10倍。同样，3D-ATAS的υ和E都是横观各向同性的。Damage evolution and failure mechanism of 2.5D woven composite tubes under quasi-static lateral compressionYajuan Wang, Zunqing Wang, Xiaoxu Wang, Diantang Zhangdoi:10.1016/j.compstruct.2024.118635 准静态侧向压缩下2.5D编织复合材料管的损伤演化及破坏机制2.5D woven composites are ideal candidate materials for deep-sea pressure tubes owing to their excellent out-of-plane properties. This paper presents the damage evolution and failure mechanism of 2.5D woven composite tubes under quasi-static lateral compression. To conduct this study, 2.5D woven composite tubes with different thickness-to-diameter ratios, 0.04, 0.07 and 0.10, were designed and prepared. The quasi-static lateral compression tests were carried out in order to evaluate the progressive damage analysis, combining high speed photographic image with acoustic emission technologies. The results show that the increase of the ratio of thickness-to-diameter, the deformation and shear failure of the sample can be inhibited obviously. Due to the enhanced interlayer interaction, the lateral stiffness of the sample is obviously improved, so the lateral bearing stability of the sample is improved. When the peak load of samples with the thickness-to-diameter ratio of 0.1 reached 11.51 kN, it exceeded that of samples with thickness-to-diameter ratios of 0.04 and 0.07 by 450% and 82%, respectively. Furthermore, the failure mechanisms of samples with the thickness-to-diameter ratio of 0.1 were controlled by delamination fracture, whereas that of 0.04 and 0.07 were mainly influenced by shear failure and delamination failure, respectively.2.5维编织复合材料具有良好的面外性能，是深海压力管的理想候选材料。研究了2.5维编织复合材料管材在准静态侧向压缩作用下的损伤演化及破坏机理。为此，设计并制备了厚径比分别为0.04、0.07和0.10的2.5D编织复合材料管。将高速摄影图像与声发射技术相结合，进行了准静态侧向压缩试验，对渐进性损伤分析进行了评价。结果表明：随着厚径比的增大，试样的变形和剪切破坏得到明显抑制；由于层间相互作用增强，试样的侧移刚度明显提高，从而提高了试样的侧移承载稳定性。当厚径比为0.1的试样峰值荷载达到11.51 kN时，比厚径比为0.04和0.07的试样峰值荷载分别高出450%和82%。当厚径比为0.1时，试件的破坏机制受分层破坏控制，而当厚径比为0.04和0.07时，试件的破坏机制主要受剪切破坏和分层破坏影响。Offset-stoichiometric reflowable composite bonding method with adhesive for mitigating strict faying surface tolerancesTyler B. Hudson, Austin J. Smith, Nicholas J. McWeeney, Charles T. Dolph, Jin Ho Kang, Roberto J. Cano, Frank L. Palmieridoi:10.1016/j.compstruct.2024.118636用胶粘剂的偏移化学计量可回流复合粘接方法，以减轻严格的表面公差Inherent susceptibility of adhesive bonds to miniscule quantities of contamination can cause undetectable weakened bonds. For this reason, the Federal Aviation Administration (FAA) places strict regulations on adhesively bonded joints in primary aircraft structures. To meet certification requirements aircraft manufactures resort to redundant load paths in the form of fasteners which inherently add weight to the structure and increase manufacturing time. In prior work, a secondary bonding technique called AERoBOND was developed, which utilized off-stoichiometric epoxy-matrix resins to facilitate reflow and diffusion of the resin within the joint interface during a secondary bonding/cure process, thus achieving a bond similar to a co-cured joint. However, the AERoBOND process required tight spatial tolerances between the two parts being joined. This study examined the utilization of conventional adhesive with the AERoBOND method to act as a filler in the joint line, effectively reducing the need for tight tolerances on the joining parts and serving as a flexible alternative for existing manufacturing processes. Ultrasonic inspection, optical microscopy, and ASTM International standard tests were performed to analyze the joints for defects and to quantify the mode-I and mode-II interlaminar fracture toughness and short beam strength of the proposed methodology with varying manufacturing parameters. The comprehensive results indicate that the AERoBOND + method with and without surface preparation performs comparably to co-cured and conventional, adhesively bonded joints when secondary cured in an autoclave with 791 kPa of pressure. As an example, the AERoBOND + panel without surface preparation bonded with 791 kPa of pressure (referred to as AB + 3 throughout paper) had a mode-I fracture toughness (GIc) of 0.643 kJ/m2 and a mode-II fracture toughness (GIIc) of 4.000 kJ/m2 in the non-precracked condition and 4.218 kJ/m2 in the precracked condition at the adhesive-to-prepreg interface. These results were 96 %, 142 %, and 217 %, respectively, of a co-cured baseline panel (referred to as C1 throughout paper).黏合剂对微量污染的固有敏感性会导致无法检测到的黏合剂减弱。出于这个原因，美国联邦航空管理局（FAA）对飞机主要结构中的粘合接头进行了严格的规定。为了满足认证要求，飞机制造商采用紧固件形式的冗余负载路径，这必然会增加结构的重量并增加制造时间。在之前的研究中，研究人员开发了一种名为aeroond的二次键合技术，该技术利用非化学计量环氧基树脂，在二次键合/固化过程中促进树脂在接头界面内的回流和扩散，从而获得类似于共固化接头的键合。然而，aeroond工艺要求连接的两个零件之间有严格的空间公差。本研究研究了传统粘合剂与aeroond方法在连接线上作为填料的使用，有效地减少了对连接部件的紧密公差的需求，并作为现有制造工艺的灵活替代方案。采用超声检查、光学显微镜和ASTM国际标准测试来分析接头的缺陷，并量化该方法在不同制造参数下的i型和ii型层间断裂韧性和短梁强度。综合结果表明，当在压力为791 kPa的高压灭菌器中进行二次固化时，加表面处理和不加表面处理的aeroond + 方法的性能与共固化和常规粘合接头相当。例如，在791 kPa压力下粘合的未经表面处理的AERoBOND + 面板（文中称AB + 3），在胶粘剂-预浸料界面处，无预裂状态下的i型断裂韧性（GIc）为0.643 kJ/m2，预裂状态下的ii型断裂韧性（GIIc）为4.000 kJ/m2，预裂状态下为4.218 kJ/m2。这些结果分别为96 %，142 %和217 %的共固化基线面板（在整篇论文中称为C1）。Comprehensive stress-driven multi-material problem for heat-sinking heterogeneous structuresThanh T. Banh, Son H. Nguyen, Dongkyu Leedoi:10.1016/j.compstruct.2024.118638热沉非均质结构的综合应力驱动多材料问题In the realm of designing thermoelastic structures, particularly within aerospace and broader engineering fields, complex challenges arise from the diverse behaviors of heterogeneous materials and the intricate requirements of stress-based systems in coupled thermomechanical considerations. This study addresses these challenges by proposing a comprehensive methodology with two main contributions: (i) the development of an effective unified solution for stress-driven designs that tackle heat-sinking problems by accommodating a wide range of materials, from homogeneous to heterogeneous and (ii) the introduction of a robust stress-based optimization approach for multi-material problems within coupled thermomechanical systems. The methodology employs the well-established P-norm approach to consolidate heterogeneous stresses into a unified global metric. Additionally, it integrates effective material interpolation with the generalized Solid Isotropic Material with Penalization (SIMP) framework, resulting in comprehensive multi-material models that include the constitutive matrix, thermal conductivity, thermal stress coefficient, and thermoelastic stress distributions. To further enhance adaptability and flexibility, the methodology incorporates a polygonal discretization technique. Detailed sensitivity analyses, using the adjoint variable technique, are conducted to improve computational efficiency in gradient-based mathematical programming algorithms. The efficiency, robustness, and practicality of the proposed methodology are validated through numerical examples, demonstrating its effectiveness and reliability in real-world applications.在设计热弹性结构的领域，特别是在航空航天和更广泛的工程领域，复杂的挑战来自于非均质材料的不同行为和耦合热机械考虑的基于应力的系统的复杂要求。本研究通过提出一种综合的方法来解决这些挑战，该方法有两个主要贡献：(i)为应力驱动设计开发了一种有效的统一解决方案，通过适应从均匀到非均匀的广泛材料来解决热沉问题；（ii）为耦合热机械系统中的多材料问题引入了一种强大的基于应力的优化方法。该方法采用公认的方法P-norm方法将异质应力合并为统一的全局度量。此外，它还将有效材料插值与广义固体各向同性材料惩罚（SIMP）框架相结合，形成了包括本构矩阵、导热系数、热应力系数和热弹性应力分布在内的综合多材料模型。为了进一步提高适应性和灵活性，该方法采用了多边形离散化技术。利用伴随变量技术进行了详细的灵敏度分析，以提高基于梯度的数学规划算法的计算效率。通过数值算例验证了该方法的有效性、鲁棒性和实用性，证明了该方法在实际应用中的有效性和可靠性。Investigation into the quasi-static/dynamic combined shear-compression behaviors of three honeycomb like structuresGuijia Gao, Haohua Li, Haibiao Lu, Weili Ren, Yunbo Zhong, Zuosheng Leidoi:10.1016/j.compstruct.2024.118639三种蜂窝状结构的准静/动联合剪切压缩特性研究To provide a refined guide for the design and application of optimal crystalline cellular structures (OCCS), an in-depth investigation into the quasi-static and dynamic combined shear-compression behaviors of single-layer (Hp-structure) and double-layer (Hc-structure and T-structure) OCCS with varying relative densities (ρr) has been undertaken. First, the three structures of AlSi10Mg with a ρr of 25.84 % are manufactured via 3D printing. Then, a battery of quasi-static and dynamic pure compression tests is executed to elucidate the mechanical responses of these structures. Finally, a numerical study is used for exploring the influence of ρr on their quasi-static/dynamic combined shear-compression behaviors. The quasi-static/dynamic pure compression results show that, for different compression parameters (σpk, σpl, σm, EA, SEA), the optimal structural representatives (Hp-structure, Hc-structure, or T-structure) in different ρr ranges are identified. The dynamic compression deformation mechanisms and theoretical analyses of Hc-structure and T-structure are proposed. As shear angle increases, the shear-compression performance of Hp-structure significantly decreases, while those of Hc-structure and T-structure gradually decrease. Fitted quasi-static/dynamic initial yield envelopes are used to provide design criteria for OCCS.为了为优化晶体单元结构(OCCS)的设计和应用提供更精细的指导，对单层(Hp结构)和双层(Hc结构和T结构)OCCS在不同相对密度(ρr)下的准静态和动态剪切-压缩行为进行了深入研究。首先，通过3D打印制造了AlSi10Mg的三种结构，其ρr为25.84%。然后，执行了一系列准静态和动态纯压缩试验，以阐明这些结构的机械响应。最后，使用数值研究探索了ρr对它们准静态/动态剪切-压缩行为的影响。准静态/动态纯压缩结果表明，对于不同的压缩参数(σpk、σpl、σm、EA、SEA)，在不同的ρr范围内可以确定最佳结构代表(Hp结构、Hc结构或T结构)。提出了Hc结构和T结构的动态压缩变形机制和理论分析。随着剪切角的增大，Hp结构的剪切-压缩性能显著降低，而Hc结构和T结构的剪切-压缩性能则逐渐降低。采用拟静力/动态初始屈服包络曲线来为OCCS提供设计准则。On the bending, buckling and free vibration analysis of bio-inspired helicoidal laminated composite shear and normal deformable beamsArmagan Karamanli, Thuc P. Vo, Mohamed-Ouejdi Belarbi, Seunghye Leedoi:10.1016/j.compstruct.2024.118641仿生螺旋层合复合材料剪切和法向变形梁的弯曲、屈曲和自由振动分析The mechanical behaviours of bio-inspired helicoidal symmetric laminated composite (BIHLC) beams are investigated via the Ritz method. By exploiting the variational formulation, equations of motion along with element stiffness, geometrical stiffness, and mass matrices are derived. The study conducts a thorough examination, covering bending, buckling stability, and free vibration analyses of BIHLC beams with various lamination schemes. The developed model is verified against existing literature on conventional composite laminated and BIHLC beams. The study also examines the mechanical response of BIHLCs, considering boundary conditions, lamination schemes, orthotropy ratios, and aspect ratios. Notably, deflections, critical buckling loads, and fundamental frequencies demonstrate variations dependent on the specific lamination scheme, boundary condition, and aspect ratio. Novel findings, presented for the first time, offer valuable insights for future studies in this area.采用里兹方法研究了仿生螺旋对称层合复合材料（BIHLC）梁的力学行为。利用变分公式,运动方程以及元素刚度、几何刚度和质量矩阵。该研究进行了全面的研究，包括不同层压方案的BIHLC梁的弯曲，屈曲稳定性和自由振动分析。将所建立的模型与已有的传统复合材料层合梁和BIHLC梁进行了对比验证。该研究还考察了bihlc的力学响应，考虑了边界条件、层压方案、正交异性比和纵横比。值得注意的是，挠度、临界屈曲载荷和基频的变化取决于特定的层压方案、边界条件和长径比。本文首次提出的新发现，为该领域的未来研究提供了有价值的见解。Vibration suppression characteristics of a thin sandwich panel with misaligned stacking spider-web-like phononic crystal coresFulong Zhao, Tongtong Huo, Zhijing Wu, Fengming Lidoi:10.1016/j.compstruct.2024.118642蛛网状声子晶体芯错位叠层夹层板的振动抑制特性A novel spider-web-like multi-hole variable cross-section phononic crystal (VCSPC) is proposed in this study, along with a misaligned stacking approach for constructing thin sandwich panels to achieve lightweight and compact structures for low-frequency vibration suppression. The band-gap (BG) characteristics and vibration modes are analyzed using the finite element method (FEM). To validate the effectiveness of the misaligned stacking approach, the finite element simulation and experimental verification of the frequency response function (FRF) are conducted. The results demonstrate that the spider-web-like configuration, with distributed masses and periodically varying cross-sections, can reduce the opening frequencies of BGs. When compared to the conventional linearly arranged panel, the misaligned stacking structure exhibits equivalent vibration BGs and attenuation characteristics. It is important to note that the misaligned stacking design significantly reduces the size in the direction of vibration attenuation. This type of thin sandwich panel is well-suited for engineering environments with size limitations on vibration reduction structures. The proposed strategy facilitates the use of large-scale phononic crystals for low-frequency vibration control, thereby promoting the application of phononic crystals in engineering through a more compact structural design.本研究提出了一种新型的类似蜘蛛网的多孔可变截面声子晶体（VCSPC），以及一种用于构建薄夹层板的错位堆叠方法，以实现轻量化和紧凑的结构，用于低频振动抑制。采用有限元法分析了带隙特性和振动模式。为了验证错向叠加方法的有效性，进行了有限元仿真和频响函数（FRF）实验验证。结果表明，具有分布质量和周期性截面变化的蛛网状结构可以降低BGs的开启频率。与传统的线性排列面板相比，错位堆叠结构具有等效的振动BGs和衰减特性。值得注意的是，不对齐的堆叠设计在振动衰减方向上显著减小了尺寸。这种薄型夹层板非常适合减振结构尺寸限制的工程环境。该策略有利于利用大规模声子晶体进行低频振动控制，从而通过更紧凑的结构设计促进声子晶体在工程中的应用。An interpretable machine learning-based model for shear resistance prediction of CFRP-strengthened RC beams using experimental and synthetic datasetAmirhossein Mohammadi, Joaquim A.O. Barros, José Sena-Cruzdoi:10.1016/j.compstruct.2024.118632基于实验和合成数据集的cfrp加固RC梁抗剪抗力预测的可解释机器学习模型Existing analytical models for predicting the shear resistance of RC beams strengthened with externally bonded CFRP reinforcements exhibit deficient performance due to their inability to accurately capture the complex resisting mechanisms. Combined with significant statistical uncertainties in shear failure, driven by its brittle nature, this further undermines the reliability of these models. To address these limitations, this study leverages Machine Learning (ML) to develop more robust and reliable predictive tool. A rigorous feature-selection process identified eight predictors as the most influential. Subsequently, nine ML-algorithms were trained on a refined experimental dataset comprising 239 beams, with XGBoost emerging as the top performer. This model also outperformed established models likefib Bulletin-90 and ACI 2023 models. However, the limited scope of the experimental dataset constrained the model’s predictive performance especially when separately evaluated on beams strengthened with U-wraps, full wraps or side-bonded FRP configurations. Therefore, to achieve a more reliable model a synthetic dataset was generated using Tabular Variational Auto-Encoder. The XGBoost model trained with the synthetic dataset significantly improved the performance of the former model and exhibited better predictions for all strengthening configurations. Finally, to ensure the physical consistency of predictions, values obtained from the SHapley Additive exPlanations method were analysed.现有的预测外粘结碳纤维布加固RC梁抗剪能力的分析模型由于无法准确捕捉复杂的抗剪机制而表现出不足的性能。再加上剪切破坏中显著的统计不确定性，由其脆性驱动，这进一步破坏了这些模型的可靠性。为了解决这些限制，本研究利用机器学习（ML）来开发更强大、更可靠的预测工具。一个严格的特征选择过程确定了八个最具影响力的预测因素。随后，在包含239束的精炼实验数据集上训练了9种ml算法，其中XGBoost表现最佳。该模型也优于fib Bulletin-90和ACI 2023等已建立的模型。然而，实验数据集的有限范围限制了模型的预测性能，特别是在分别评估用u型包层、全包层或侧粘合FRP结构加固的梁时。因此，为了获得更可靠的模型，使用表格变分自编码器生成合成数据集。使用合成数据集训练的XGBoost模型显著提高了前模型的性能，并且对所有强化配置都有更好的预测。最后，为了确保预测的物理一致性，分析了SHapley加性解释方法获得的值。Topology optimization based on the improved high-order RAMP interpolation model and bending properties research for curved square honeycomb sandwich structuresXu Zhang, Gao Duan, Yan Fang, Xuechuan Yin, Wei Lidoi:10.1016/j.compstruct.2024.118643基于改进高阶RAMP插值模型的弯曲方形蜂窝夹层结构拓扑优化及弯曲性能研究Curved honeycomb sandwich structures with larger surface areas effectively reduce the number of fasteners and connectors, resulting in weight reduction, cost savings, and reliability improvement. Square honeycombs exhibit higher in-plane tensile strength, and are more compatible with mechanical components. Topology optimization can realize the variable-density design of square honeycombs, enhancing the strength and stiffness of curved sandwich structures, but the high-order Rational Approximation of Material Properties (RAMP) interpolation model with a fast convergence rate has the relatively poor clarity and stability in topology boundaries. Hence, a variable-density topology optimization method based on the improved high-order RAMP model is developed for curved square honeycomb sandwich structures. The high-order RAMP interpolation model is improved by incorporating a minimum modulus term into the material interpolation function and employing the Bi-directional Evolutionary Structural Optimization (BESO) to refine the Optimality Criteria (OC) method. A functional relationship between the wall thickness of cross-shaped cells (i.e., simplified models of four adjacent square cells arranged in a cross) and the relative density of topology units is constructed using a density mapping method, and the topology optimization with the relative density of cross-shaped cells as the design variable is performed to minimize the compliance of the core. Three-point bending tests are conducted on 3D printed non-optimized and optimized curved honeycomb sandwich structures with different core material retention rates and panel thicknesses, and the experimental results are compared with those of simulations to explore the bending properties and failure behaviors. The results indicate that the modified high-order RAMP interpolation model enhances the clarity and stability of topology structures, the variable-density topology optimization significantly improves the bending properties of curved square honeycomb sandwich structures, and the experimental and numerical results are largely consistent.曲面蜂窝夹层结构具有更大的表面积，有效地减少了紧固件和连接器的数量，从而减轻了重量，节省了成本，提高了可靠性。方形蜂窝具有更高的面内抗拉强度，与机械部件的相容性更好。拓扑优化可以实现方形蜂窝的变密度设计，提高弯曲夹层结构的强度和刚度，但收敛速度快的材料性能高阶有理逼近（RAMP）插值模型在拓扑边界上的清晰度和稳定性相对较差。为此，提出了一种基于改进的高阶RAMP模型的曲面方形蜂窝夹层结构变密度拓扑优化方法。通过在材料插值函数中引入最小模量项，并采用双向进化结构优化（BESO）对优化准则（OC）方法进行改进，改进了高阶RAMP插值模型。采用密度映射的方法，建立了十字形单元壁厚（即四个相邻方形单元排成十字形排列的简化模型）与拓扑单元相对密度之间的函数关系，并以十字形单元相对密度为设计变量进行拓扑优化，以最小化芯的柔度。对3D打印非优化和优化后的弯曲蜂窝夹层结构在不同芯材保留率和面板厚度下进行三点弯曲试验，并将实验结果与模拟结果进行对比，探讨弯曲性能和破坏行为。结果表明：改进的高阶RAMP插值模型增强了拓扑结构的清晰性和稳定性，变密度拓扑优化显著改善了弯曲方形蜂窝夹层结构的弯曲性能，实验结果与数值结果基本一致。Composites Part A: Applied Science and ManufacturingInvestigation of the notch sensitivity of tailorable long fiber discontinuous prepreg composite laminatesDrew E. Sommer, Sergii G. Kravchenko, R. Byron Pipesdoi:10.1016/j.compositesa.2024.108508定制型长纤维不连续预浸复合材料层合板缺口灵敏度的研究Tailorable discontinuous fiber composite laminates provide relative formability beyond that of continuous fiber laminates, while achieving improved mechanical performance over comparable stochastic systems. In this work, the notch sensitivity of engineered prepreg platelet molded composite (PPMC) laminates is investigated using the open-hole tension (OHT) test and compared to available data for stochastic PPMCs and continuous fiber laminates made with the same material. The press-formed thermoplastic composites (AS4/PEKK) were molded with a quasi-isotropic stacking sequence. The discontinuous PPMC laminate was found to be notch insensitive with OHT strengths ranging from 145.4 MPa (CV = 7%) for d/w=0.5 to 229.3 MPa (CV=9%) for d/w = 0.25. The highly ordered meso-structure of the engineered PPMC laminate yields comparatively excellent mechanical properties for relatively thin laminates in contrast to stochastic systems. Both net- and gross-section failures were observed for d/w = 0.25, which suggests that the engineered PPMC laminates studied here maintain a degree of inherent, internal stress concentrations that compete with those caused by geometric features such as a circular hole. Computational simulations of the OHT tests with explicitly represented platelets were found to be in good agreement with experimental measurements. The progressive failure analysis was used to conduct a numerical investigation of the stacking sequence and platelet meso-morphology.可定制的不连续纤维复合材料层合板在相对成形性方面超越了连续纤维层合板，同时在与之相当的随机系统中实现了更好的机械性能。在这项工作中，对工程预浸料片状模塑料（PPMC）层合板的缺口敏感性进行了研究，并与使用相同材料的随机PPMC和连续纤维层合板的数据进行了比较。采用开放式孔拉伸（OHT）试验对热塑性复合材料（AS4/PEKK）进行压模成型，采用准各向同性堆叠顺序。发现不连续PPMC层合板对缺口不敏感，OHT强度范围为145.4 MPa（CV=7%）至229.3 MPa（CV=9%），其中d/w=0.5至0.25。工程PPMC层合板的高有序微观结构使其在相对薄的层合板中具有与随机系统相比极为出色的机械性能。对于d/w=0.25的情况，既观察到了网格断裂，也观察到了体积断裂，这表明这里研究的工程化PPMC层合板在某种程度上仍然保留着内在的、与几何特征（如圆孔）竞争的应力集中现象。对OHT试验进行的计算机模拟，其结果与实验测量结果相吻合。采用渐进失效分析方法对层压顺序和片材微观形态进行了数值研究。Epoxy microlattice with simultaneous self-sensing and electromagnetic interference shielding performance by in-situ additive manufacturingZhenyu Wang, Daopeng Qu, Tao Zhang, Chenxi Hua, Xinyu Song, Ming Li, Xi Shen, Yu Liudoi:10.1016/j.compositesa.2024.108521原位增材制造同时具有自传感和电磁干扰屏蔽性能的环氧微晶格The development of epoxy nanocomposite architectures capable of self-sensing the internal structural response to mechanical stimuli and exhibiting multifunctionality represents a significant challenge to the scientific community. Here, an in-situ additive manufacturing technique is developed to construct robust SiO2/epoxy host material and piezoresistive nanocarbon/epoxy sensing elements into an engineered 3D microlattice. The integration of microscale sensing elements with tailored embedment locations and contents enables the real-time detection of in-situ strain under varying loadings, without compromising the mechanical properties of the original host structure. Additionally, the epoxy microlattices containing 3D interconnected network of sensing elements present excellent electromagnetic interference shielding properties, attaining a high shielding effectiveness of up to 33 dB. Furthermore, the applications of the epoxy microlattice in defect-recognizable composite lattices and multifunctional protective devices are demonstrated. The present findings suggest an effective strategy for the development of intrinsically smart epoxy nanocomposites with customized microstructure and unprecedented multifunctionality.环氧纳米复合材料结构的发展能够自我感知内部结构对机械刺 激的反应，并表现出多功能性，这对科学界来说是一个重大挑战。在这里，开发了一种原位增材制造技术，将坚固的SiO2/环氧树脂主体材料和压阻性纳米碳/环氧树脂传感元件构建成工程三维微晶格。微型传感元件与定制的嵌入位置和内容的集成可以实时检测不同载荷下的原位应变，而不会影响原始主体结构的机械性能。此外，含有三维互连传感元件网络的环氧微晶格具有优异的电磁干扰屏蔽性能，屏蔽效率高达33 dB。此外，还介绍了环氧微晶格在缺陷识别复合晶格和多功能保护器件中的应用。本研究结果为开发具有定制结构和前所未有的多功能性的本质智能环氧纳米复合材料提供了有效的策略。Arχi-Textile composites: Role of weave architecture on mode-I fracture energy in woven compositesHridyesh Tewani, Jackson Cyvas, Kennedy Perez, Pavana Prabhakardoi:10.1016/j.compositesa.2024.108499Arχi-Textile 复合材料： 编织结构对编织复合材料 I 型断裂能的影响This paper investigates the impact of weave architectures on the mechanics of crack propagation in fiber-reinforced woven polymer composites under quasi-static loading. Woven composites consist of fabrics/textiles containing fibers interwoven at 0 degrees (warp) and 90 degrees (weft) bound by a polymer matrix. The mechanical properties can be tuned by weaving fiber bundles with single or multiple materials in various patterns or architectures. Although the effects of uniform weave architectures, like plain, twill, satin, etc. on in-plane modulus and fracture energy have been studied, the influence of patterned weaves consisting of a combination of sub-patterns, that is, architected weaves, on these behaviors is not understood. We focus on identifying the mechanisms affecting crack path tortuosity and propagation rate in composites with architected woven textiles containing various sub-patterns, hence, Arχi(ar.kee)-Textile Composites. Through compact tension tests, we determine how architected weave patterns compared to uniform weaves influence mode-I fracture energy of woven composites due to interactions of different failure modes. Results show that fracture energy increases at transition regions between sub-patterns in architected weave composites, with more tortuous crack propagation and higher resistance to crack growth than uniform weave composites. We also introduce three geometrical parameters — transition, area, and skewness factors — to characterize sub-patterns and their effects on in-plane fracture energy. This knowledge can be exploited to design and fabricate safer lightweight structures for marine and aerospace sectors with enhanced damage tolerance under extreme loads.本文研究了在准静态加载条件下，编织结构对纤维增强编织聚合物复合材料裂纹扩展力学的影响。编织复合材料由织物/纺织品组成，其中的纤维以 0 度（经线）和 90 度（纬线）交织，并与聚合物基体结合在一起。通过将纤维束与单种或多种材料以不同的模式或结构进行编织，可以调整机械性能。虽然已经研究了平纹、斜纹、缎纹等均匀编织结构对平面模量和断裂能的影响，但还不清楚由子图案组合而成的图案编织（即编织结构）对这些行为的影响。我们的研究重点是确定影响包含各种子图案的拱形编织复合材料（即 Arχi(ar.kee)-Textile 复合材料）裂纹路径曲折性和传播速度的机制。通过紧凑拉伸试验，我们确定了与均匀编织相比，拱形编织图案如何因不同失效模式的相互作用而影响编织复合材料的模式 I 断裂能。结果表明，与均匀编织复合材料相比，拱形编织复合材料中子图案之间过渡区域的断裂能增加，裂纹扩展更曲折，裂纹增长阻力更大。我们还引入了三个几何参数--过渡、面积和偏斜系数--来描述子图案及其对平面内断裂能的影响。利用这些知识，我们可以为海洋和航空航天领域设计和制造更安全的轻质结构，并提高在极端负荷下的损伤耐受性。Impact sensing, localization and damage assessment in Fiber-Reinforced composites with ZnO Nanowires-Based sensor arraySiyi Cheng, Xiaoming Chen, Han Zhang, Kaiqiang Wen, Yaozu Hui, Yijie Wang, Hechuan Ma, Xin Wang, Jie Zhang, Jinyou Shaodoi:10.1016/j.compositesa.2024.108517 基于ZnO纳米线传感器阵列的纤维增强复合材料冲击传感、定位和损伤评估The structural integrity and monitoring of load distributions in composites are critical for safety and economic efficiency but still challenging. Herein, zinc oxide nanowires (ZnO NWs) were embedded into a carbon fiber-reinforced composite serving as mechanical reinforcement and sensing components. The presence of ZnO NWs in the composite material increased the flexural strength, interlaminar, and interfacial shear strength by respectively 4.9 %, 8.8 %, and 19.9 % due to the strong bonding at the fiber/resin interface and the mechanical interlocking effect. Additionally, the piezoelectric nature of ZnO NWs with an asymmetric crystal structure generated piezoelectric charges under stress, thereby enhancing the sensitivity of capacitive monitoring. A self-developed algorithm was then designed to analyze the array capacitance changes collected from the prepared composite laminate to determine the impact load with high precision with an error margin of 3 mm and not exceeding 0.25 MPa. Furthermore, damage was also able to be detected by monitoring capacitance changes. Overall, the proposed high-precision and minimally aggressive approach for load localization and quantification provides a promising direction and strategic pathway for the development of smart self-monitoring composites.复合材料的结构完整性和载荷分布监测对安全性和经济性至关重要，但仍然具有挑战性。本文将氧化锌纳米线（ZnO NWs）嵌入碳纤维增强复合材料中，作为机械增强和传感元件。ZnO纳米粒子的存在使复合材料的抗弯强度、层间剪切强度和界面剪切强度分别提高了4.9 %、8.8 %和19.9 %，这是由于纤维/树脂界面处的强结合和机械联锁效应。此外，具有不对称晶体结构的ZnO NWs的压电性质在应力作用下产生压电电荷，从而提高了电容监测的灵敏度。然后设计了一种自行开发的算法，对制备的复合材料层压板采集的阵列电容变化进行分析，以高精度确定冲击载荷，误差范围为3 mm，不超过0.25 MPa。此外，还可以通过监测电容变化来检测损伤。总之，本文提出的高精度、最小侵略性的载荷定位和量化方法为智能自监测复合材料的发展提供了一个有前途的方向和战略途径。Transverse squeeze flow of thermoplastic composite tape during in-situ consolidation via automated fiber placementMahmoud Fereidouni, Suong Van Hoadoi:10.1016/j.compositesa.2024.108519热塑性复合胶带在原位固结过程中的横向挤压流动Transverse squeezing of thermoplastic composite tapes during automated fiber placement is a challenge in controlling gaps/overlaps of adjacent bands. A theoretical model may provide insights on direct effect of process parameters on deformation of tape. The developed models in this work evaluate non-Newtonian squeeze flow of molten tape using power-law viscosity under three different no slip, perfect slip, and imperfect slip boundary conditions at interface during in-situ consolidation, aiming to predict the final width of tape with minimal computational costs. The results predicted by models are verified using finite element analysis with close agreement. Subsequently, no slip and perfect slip assumptions underestimated and overestimated the experimental measurements of consolidated widths, respectively. However, the squeeze model with imperfect slip condition may effectively capture the trends in the experimental data. This model includes the effect of intimate contact development on the friction parameter during squeezing, utilizing a new non-Newtonian trapezoidal asperity model.在自动铺布过程中，热塑性复合材料带的横向挤压是控制相邻带间隙/重叠的挑战。理论模型可以提供对工艺参数对胶带变形的直接影响的见解。本文建立的模型利用幂律黏度在现场固结过程中三种不同的界面无滑移、完全滑移和不完全滑移边界条件下对熔融带的非牛顿挤压流动进行了评估，旨在以最小的计算成本预测带的最终宽度。用有限元分析验证了模型预测的结果，结果非常吻合。因此，无滑移假设和完全滑移假设分别低估和高估了固结宽度的实验测量值。然而，不完全滑移条件下的挤压模型可以有效地捕捉实验数据中的趋势。该模型采用一种新的非牛顿梯形粗糙度模型，考虑了挤压过程中密切接触发展对摩擦参数的影响。Crystallinity of neat and carbon fiber-reinforced polyamide-6 processed at different cooling ratesS. Simaafrookhteh, Thijs Van Thillo, S.V. Lomov, J. Ivensdoi:10.1016/j.compositesa.2024.108520不同冷却速率下纯聚酰胺和碳纤维增强聚酰胺-6的结晶度The cooling rate of the manufacturing process can significantly alter the performance of the semi-crystalline polymers and composites by influencing their degree of crystallinity (DOC). To this end, the research studies the cooling rate effect on the crystallization of injection-molded polyamide-6 (PA6) and carbon fiber-reinforced PA6 (CF/PA6) compression-molded laminates. DSC, mDSC, and XRD techniques are used and compared for DOC characterization while highlighting the challenges and possible erroneous results when using DSC and XRD. mDSC results after careful drying and storage and due to the capacity of the technique to separate the reversing and non-reversing signals showed consistent results, while the XRD underestimates the DOC. Based on mDSC, different cooling methods of the compression molding process induced DOCs in the 36–50 % range for the CF/PA6 laminates, whereas changing the mold temperature of the injection molding process resulted in PA6 films with DOC of 28–35 %.制备过程中的冷却速率可以通过影响半结晶聚合物和复合材料的结晶度（DOC）来显著改变其性能。为此，研究了冷却速率对注塑成型聚酰胺-6 （PA6）和碳纤维增强PA6 （CF/PA6）压塑层压板结晶的影响。使用DSC， mDSC和XRD技术进行DOC表征并进行比较，同时强调使用DSC和XRD时面临的挑战和可能出现的错误结果。mDSC结果经过仔细的干燥和储存，并且由于该技术能够分离反转和非反转信号，结果一致，而XRD低估了DOC。在mDSC的基础上，不同冷却方式对CF/PA6层压板的DOC影响范围在36-50 %之间，而改变注塑过程的模具温度对PA6层压板的DOC影响范围为28-35 %。Composites Part B: EngineeringAll-polymer syntactic foams: Linking large strain cyclic experiments to Quasilinear Viscoelastic modelling for materials characterisationSy-Ngoc Nguyen, Riccardo De Pascalis, Zeshan Yousaf, William J. Parnelldoi:10.1016/j.compositesb.2024.111866全聚合物合成泡沫：将大应变循环实验与材料表征的准线性粘弹性模型联系起来The time-dependent behaviour of polymeric composites is critical in a broad range of applications, including those in marine, aerospace, and automotive environments. In the present study, we assess the validity of the quasi-linear viscoelastic (QLV) model to fit the stress–strain behaviour of all-polymer syntactic foams under large cyclic compressional strain in a novel experimental configuration. These syntactic foams were manufactured by adding hollow polymer microspheres of various sizes and wall thicknesses into a polyurethane matrix. These materials are known for their relatively large initial stiffness, and strong recoverability after large strains. In the QLV model, several strain energy functions (SEFs) were employed, including neo-Hookean, Ogden type I, and type II. The bulk and shear moduli are presented in the form of a Prony series. By estimating these experimental data using optimisation, the natural viscoelastic material properties and coefficients associated with the SEF were determined. The influence of the microsphere filling fraction was also explored. We show that at the strain rate considered here of 0.013 s − 1 , the compressible QLV model coupled with the Ogden-I SEF is capable of providing an excellent fit to experimental data. Critically, this fit can be achieved over a range of cycles via model optimisation to the first cyclic response only.聚合物复合材料的时间依赖性行为在包括船舶、航空航天和汽车环境在内的广泛应用中至关重要。在本研究中，我们评估了准线性粘弹性（QLV）模型在大循环压缩应变下拟合全聚合物复合泡沫的应力-应变行为的有效性。这些合成泡沫是通过在聚氨酯基体中加入不同尺寸和壁厚的中空聚合物微球来制造的。这些材料以其相对较大的初始刚度和大应变后的强恢复性而闻名。在QLV模型中，采用了几种应变能函数（sef），包括neo-Hookean、Ogden I型和II型。体模量和剪切模量以普罗尼级数的形式表示。通过对这些实验数据进行优化估计，确定了与SEF相关的天然粘弹性材料性能和系数。探讨了微球填充率的影响。我们表明，在0.013 s−1的应变速率下，与Ogden-I SEF耦合的可压缩QLV模型能够很好地拟合实验数据。关键的是，这种拟合可以在一系列周期内通过模型优化来实现，仅针对第一个周期响应。Internal Damage Evolution of C/SiC Composites in Air at 1650 °C Studied by in-situ Synchrotron X-ray ImagingLi Xi, Shaoling Li, Kaiyuan Xue, Xiaochuan Cui, Bowen Wang, Ying Li, Daining Fangdoi:10.1016/j.compositesb.2024.111878原位同步辐射x射线成像研究C/SiC复合材料在1650℃空气中的内部损伤演化Carbon fibre reinforced silicon carbide (C/SiC) ceramic matrix composites have attracted considerable attention due to their exceptional properties and extensive potential applications as high-temperature structural materials. However, due to their complex structure and manufacturing defects, C/SiC composites exhibit intricate mechanical behavior under thermal-mechanical-oxidative coupling environments. To date, systematic studies on the internal damage evolution and failure mechanisms of C/SiC composites under high-temperature oxidative environments are lacking. In this study, a combination of synchrotron X-ray micro-computed tomography (SR-μCT) and in-situ experiments under thermal-mechanical-oxidative coupling environments at room temperature and 1650 °C in air was used to characterize the internal microstructures and damage evolution processes of C/SiC composites at different loading levels. Additionally, the 3D strain fields during in-situ loading were quantitatively analyzed using the Digital Volume Correlation (DVC) method. The findings underscore the substantial impact of oxidative damage on the mechanical response of C/SiC composites, particularly concerning tensile properties and fracture modes. At room temperature, severe delamination, fibre bundle pull-out and interfacial debonding occurred internally. Whereas, under high-temperature atmospheric conditions, severe fibre oxidation reactions occurred at the specimen edges, resulting in rapid porosity escalation. Crack initiation from surface defects followed by rapid inward propagation is observed. Moreover, while the strain distribution remains relatively uniform until fracture, a pronounced concentration of strain is evident near the fracture zones at room temperature, with an even greater concentration observed at 1650 °C. Notably, the region of concentrated strain within the 3D deformation field corresponds closely to the final fracture location, as revealed by quantitative DVC analysis.碳纤维增强碳化硅（C/SiC）陶瓷基复合材料因其优异的性能和作为高温结构材料的广泛应用前景而受到广泛关注。然而，由于其复杂的结构和制造缺陷，C/SiC复合材料在热-机械-氧化耦合环境下表现出复杂的力学行为。迄今为止，对高温氧化环境下C/SiC复合材料内部损伤演化及破坏机制的系统研究尚缺乏。本文采用同步加速器x射线微计算机断层扫描（SR-μCT）和原位实验相结合的方法，在室温和空气1650℃的热-机械-氧化耦合环境下，对不同加载水平下C/SiC复合材料的内部组织和损伤演化过程进行了表征。此外，采用数字体积相关（DVC）方法对原位加载过程中的三维应变场进行了定量分析。研究结果强调了氧化损伤对C/SiC复合材料力学响应的重大影响，特别是在拉伸性能和断裂模式方面。在室温下，内部发生了严重的分层、纤维束拔出和界面脱粘。然而，在高温大气条件下，试样边缘发生严重的纤维氧化反应，导致孔隙率迅速上升。裂纹从表面缺陷开始，然后迅速向内扩展。此外，虽然应变分布在断裂前保持相对均匀，但在室温下，在断裂区附近明显存在明显的应变集中，在1650℃时观察到的应变集中更大。值得注意的是，通过定量DVC分析，三维变形场内的应变集中区域与最终断裂位置紧密对应。Composites Science and TechnologyDecreasing Propagation Rate of Interfacial Debonding Between a Single Carbon Fiber and Epoxy Matrix Under Cyclic LoadingKosuke Takahashi, Takuma Matsuo, Wataru Sato, Takashi Nakamuradoi:10.1016/j.compscitech.2024.110900 循环加载下降低单碳纤维与环氧基界面脱粘扩展速率的研究The interfacial debonding of a single carbon fiber transversely embedded in a dumbbell-shaped epoxy sample was generated under cyclic loading, and images were captured using synchrotron radiation X-ray computed tomography. A fatigue testing machine driven by a piezoelectric actuator placed along the beamline for in situ observation was developed for precise alignment. Interfacial debonding was initially observed under a static tensile load and was confirmed to be almost of the same length at both ends of the carbon fiber, implying negligible bending deformation due to inclination. Cyclic loads were then applied to the sample to capture the progressive debonding. The propagation rate of the interfacial debonding decreased as the number of cycles increased. Another sample with a single carbon fiber aligned parallel to the loading direction was prepared following a single-fiber fragmentation test. Interfacial debonding was clearly observed around the fiber breakage. Cyclic loads were also applied to this sample; however, no progression of the interfacial debonding was evident. Degradation of the interfacial strength between the carbon fiber and epoxy matrix was not confirmed under cyclic loading within the elastic deformation range.在循环载荷作用下，单碳纤维横向嵌入哑铃形环氧树脂样品中，产生了界面脱粘现象，并用同步辐射x射线计算机断层扫描技术捕获了图像。研制了一种沿光束线放置的压电致动器驱动的疲劳试验机，用于现场观测，以实现精确对准。界面剥离最初是在静态拉伸载荷下观察到的，并被证实在碳纤维的两端几乎具有相同的长度，这意味着由倾斜引起的弯曲变形可以忽略不计。然后将循环载荷应用于样品以捕获渐进的脱粘。界面脱粘的传播速率随着循环次数的增加而降低。在单纤维破碎试验之后，制备了另一种与加载方向平行的单碳纤维样品。纤维断裂周围界面明显脱粘。循环荷载也应用于该样品；然而，没有明显的界面脱粘进展。在弹性变形范围内，碳纤维与环氧基之间的界面强度在循环加载下没有退化。Influence of process parameters on the interlaminar shear strength of CF/PEEK composites in-situ consolidated by laser-assisted automated fiber placementNingguo Dong, Congcong Luan, Xinhua Yao, Zequan Ding, Yuyang Ji, Chengcheng Niu, Yaping Zheng, Yuetong Xu, Jianzhong Fudoi:10.1016/j.compscitech.2024.110902 工艺参数对激光辅助自动铺纤维原位固结CF/PEEK复合材料层间剪切强度的影响The influence of process parameters, including placement speed, laser power, tooling temperature, compaction force and tape tension, on the interlaminar shear strength of CF/PEEK components in-situ consolidated by laser-assisted automated fiber placement was systematically investigated. To examine both the individual and interactive effects of these parameters, two sets of orthogonal experiments were formulated and conducted, yielding a maximum ILSS of 70.3 MPa. Analysis of variance revealed that the interaction between laser power and placement speed had the most significant effect, followed by tooling temperature, compaction force and tape tension. Furthermore, the concept of linear energy density of consolidated segments (LEDCS) was introduced to characterize and quantify the relationship between laser power and placement speed. ILSS values exceeding 50 MPa were predicted within the LEDCS range of 1.58 J/mm to 3.75 J/mm. Finally, the failure modes of the samples were elucidated through scanning electron microscopy.系统研究了激光辅助自动铺布原位固结CF/PEEK材料的工艺参数（铺布速度、激光功率、模具温度、压实力和胶带张力）对层间剪切强度的影响。为了检验这些参数的个体效应和交互效应，我们制定并进行了两组正交实验，得到最大ILSS为70.3 MPa。方差分析结果表明，激光功率和贴片速度的交互作用最显著，其次是模具温度、压实力和胶带张力。在此基础上，引入了固结段线性能量密度的概念来表征和量化激光功率与贴片速度之间的关系。在1.58 ~ 3.75 J/mm的LEDCS范围内，预测ILSS值超过50 MPa。最后，通过扫描电镜对试样的破坏模式进行了分析。Radiation hardened MOSFETs realized by Al2O3 induced Bi-GdF3 with trapped interfacial electrons located in Ti3C2Tx frameworkTianyu Zhang, Yang Hong, Jingyang Li, Yang Li, Huiyang Zhao, Kai Cui, Wenjing Wei, Hongjun Kang, Jinzhu Wu, Wei Qin, Xiaohong Wudoi:10.1016/j.compscitech.2024.110911 由 Al2O3 诱导的 Bi-GdF3 实现的辐射硬化 MOSFET，Ti3C2Tx 框架中存在被困的界面电子The radiation resistance of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) is of great significance when applied in aerospace. However, it is still challenging to obtain MOSFETs with excellent radiation resistance. In this work, the radiation hardened MOSFETs were realized by GdF3-Al2O3@Bi-Ti3C2Tx/epoxy (MBAG/EP) polymer-based composite coating with function of trapped interfacial electrons. The radiation resistance of resultant packed MOSFET is significantly improved, showing the lower threshold voltage negative drift value (0.41 V) than the bare MOSFET (7.89 V). This is mainly attributed to the introduction of ultra-thin Al2O3 intermediate layer between Bi and GdF3, which effectively tailor electron dense and distribution for an effective electron attenuation, and thus improve the radiation resistance of the MOSFET. Theoretical calculations further reveal that the packed MOSFETs present the less shifted voltage and trapped charges compared with the pristine one. This work provides an interface engineering strategy for developing radiation hardened MOSFETs.金属氧化物半导体场效应晶体管（MOSFET）的抗辐射性能在航空航天领域的应用中具有重要意义。然而，要获得具有优异抗辐射性能的 MOSFET 仍然是一项挑战。在这项工作中，通过 GdF3-Al2O3@Bi-Ti3C2Tx/epoxy (MBAG/EP) 聚合物基复合涂层实现了具有捕获界面电子功能的辐射硬化 MOSFET。与裸 MOSFET（7.89 V）相比，封装后的 MOSFET 的抗辐射能力明显提高，阈值电压负漂移值（0.41 V）更低。这主要归功于在 Bi 和 GdF3 之间引入了超薄 Al2O3 中间层，从而有效地调整了电子密度和分布，实现了有效的电子衰减，从而提高了 MOSFET 的辐射阻抗。理论计算进一步表明，与原始 MOSFET 相比，填料 MOSFET 的偏移电压和俘获电荷更少。这项研究为开发抗辐射 MOSFET 提供了一种界面工程策略。Domain generalization-based damage detection of composite structures powered by structural digital twinCheng Liu, Yan Chen, Xuebing Xu, Wangqian Chedoi:10.1016/j.compscitech.2024.110908 基于结构数字孪生的复合材料结构损伤域泛化检测This research addresses the challenge of generalizing deep learning models for different CFRP composite structures in the task of fatigue damage detection. To overcome this challenge, knowledge distillation is employed to enhance the generalizability of deep learning models. A teacher network processes continuous wavelet transform images using Fourier transform and neural networks, while a student network distills the teacher network. This framework improves the models' generalization performance by transferring knowledge from the teacher network to the student network. Additionally, soft gradient boosting is utilized to further enhance the generalizability. By constructing a main sub-network and multiple parallel auxiliary sub-networks within the teacher network, the student network mimics the main sub-network to achieve improved accuracy in the target domain and prevent overfitting. To augment limited datasets of real CFRP monitoring signals and help to learn domain-invariant features, structural digital twin technology is leveraged to generate simulated monitoring signals, which enables the models to capture domain invariant information, significantly enhancing its performance of fatigue damage detection across different structures. Damage detection based on the generalization results between multiple Layups demonstrates a test accuracy exceeding 80 % when the monitoring data of the target CFRP structure is unavailable during training. Therefore, the cross-structure damage detection ability of the proposed approach is well proved.本研究解决了在疲劳损伤检测任务中对不同CFRP复合材料结构的深度学习模型进行泛化的挑战。为了克服这一挑战，采用知识蒸馏来增强深度学习模型的泛化能力。教师网络使用傅里叶变换和神经网络处理连续小波变换图像，而学生网络则提取教师网络。该框架通过将知识从教师网络转移到学生网络来提高模型的泛化性能。此外，利用软梯度增强进一步增强了算法的泛化能力。学生网络通过在教师网络内构建一个主子网和多个并行的辅助子网来模拟主子网，以提高目标域的精度，防止过拟合。为了增加有限的真实CFRP监测信号数据集并帮助学习域不变特征，利用结构数字孪生技术生成模拟监测信号，使模型能够捕获域不变信息，从而显著提高其跨不同结构的疲劳损伤检测性能。当训练过程中没有目标CFRP结构的监测数据时，基于多层间泛化结果的损伤检测准确率超过80%。验证了该方法的跨结构损伤检测能力。An ANN-based concurrent multiscale damage evolution model for hierarchical fiber-reinforced compositesXiaojian Han, Kai Huang, Tao Zheng, Jindi Zhou, Hongsen Liu, Zhixing Li, Li Zhang, Licheng Guodoi:10.1016/j.compscitech.2024.110910 基于人工神经网络的分层纤维增强复合材料多尺度损伤演化模型In this paper, an ANN-based concurrent multiscale damage evolution model is proposed, which is able to investigate the complex failure behaviors of hierarchical fiber-reinforced composites. In the framework of the proposed model, yarn damage evolution laws at the mesoscale are indirectly derived from the microscale representative volume element (RVE), using artificial neural networks (ANNs) as a surrogate model. A homogenized characterization method is proposed to derive the homogenized damage variables. The homogenized strain and damage variables of the microscale RVE are taken as inputs and outputs in ANNs, respectively. The dataset is generated by combining clustering with the finite element simulation. A typical kind of plain-woven composite is adopted as a benchmark material for numerical implementation and experimental verification. The numerical predictions, including the tensile properties and damage evolution, are consistent with the results from quasi-static tension experiments.本文提出了一种基于人工神经网络的并行多尺度损伤演化模型，该模型能够研究分层纤维增强复合材料的复杂破坏行为。在该模型框架中，采用人工神经网络（ann）作为替代模型，从微尺度代表体积元（RVE）中间接推导出中尺度纱线损伤演化规律。提出了一种均质化表征方法来推导均质化损伤变量。将微尺度RVE的均质应变和损伤变量分别作为神经网络的输入和输出。该数据集是通过聚类和有限元模拟相结合的方法生成的。采用一种典型的平纹编织复合材料作为基准材料进行数值实现和实验验证。数值预测结果与准静态拉伸实验结果一致，包括拉伸性能和损伤演化。Effect of Crossing Warp Arrangements on Delamination Resistance of 3D Woven Composite T-joints under In-plane Tensile LoadingZiyue Wei, Xiaogang Chen, Constantinos Soutisdoi:10.1016/j.compscitech.2024.110907 交叉经纱排列对平面内拉伸载荷下三维编织复合材料t形接头抗分层性能的影响An experimental study for investigating the delamination behaviour of 3D woven composite T-joints with weave variations and optimising weave architectures is carried out. This study involves 10 types of crossing warp architectures at the junction. Quasi-static tensile load is applied to two flanges of 3D woven composite T-joints to evaluate the in-plane mechanical performance. The crossing warp architecture effectively improves the in-plane mechanical performance. Results indicate a significant influence of crossing warp arrangements on failure modes of the 3D woven composite T-joints. The use of internal crossing warp architectures leads to severe delamination in the 3D woven composite T-joints while the composite T-joints with 3D woven external crossing warps primarily fail due to the debonding of fibres and matrix and fibre breakage. The optimal weave architecture for 3D woven composite T-joints is confirmed by analysing the in-plane mechanical behaviour with different crossing warp arrangements and proportions. Regardless of the crossing warp proportions, the external crossing warp architectures outperformed their internal counterparts in resisting delamination, resulting in a maximum increase of 68.75%, 30.04% and 116.81% in modulus, strength and failure strain respectively.针对三维机织复合材料t型接头的分层行为及编织结构优化进行了实验研究。本研究涉及10种交叉经纱结构。对三维编织复合材料t型接头的两个法兰施加准静态拉伸载荷，评价其面内力学性能。交叉经纱结构有效地提高了面内力学性能。结果表明，交叉经纱排列方式对三维编织复合材料t型接头的破坏模式有显著影响。采用内交叉经纱结构导致三维编织复合材料t型接头存在严重的分层现象，而采用三维编织外交叉经纱的复合材料t型接头主要是由于纤维与基体的脱粘和纤维断裂而失效。通过对三维编织复合材料t型接头平面内力学性能的分析，确定了不同交叉经纱排列方式和比例下的最佳编织结构。无论交叉翘曲比例如何，外部交叉翘曲结构的抗分层性能都优于内部交叉翘曲结构，其模量、强度和破坏应变的最大增幅分别为68.75%、30.04%和116.81%。Effects of SiO2-coated CNTs on the directional formation of SiC whiskers and improvement in the ablative resistance of polymer-matrix compositesLi Wang, Jiang Li, Yiwei Wang, Shihui Cheng, Chenyang Madoi:10.1016/j.compscitech.2024.110904 sio2包覆CNTs对SiC晶须定向形成及提高聚合物基复合材料耐烧蚀性能的影响As the development of hypersonic aerospace technology progresses, greater challenges are presented for solid rocket motors (SRMs) thermal protection, and the ablation performance of insulation materials needs to be further improved. Carbon nanotubes (CNTs) as a new type of reinforcing nano-filler, readily react with the oxidative components in the working gas during SRMs operation, limiting their excellent performance. In this study, we propose to coat the commonly used reinforcing filler, SiO2, on the surface of CNTs to suppress their susceptibility to oxidation and investigate the effects of adding CNTs, SiO2, and CNTs@SiO2 to the matrix on material properties. The results show that the addition of CNTs@SiO2 significantly improves the ablation resistance of the insulation material, with the linear ablation rate of M-@SiO2-2 being 56% lower than that of M-SiO2-2. Based on the analysis of the material's antioxidation performance and the strength of the resulting char layer after ablation, the reasons for the improvement of ablation performance are discussed. By conducting high-temperature tube furnace tests, the composition and structure of the char layer at different temperatures are studied, and it is found that CNTs in the CNTs@SiO2 formulation can directly provide the carbon source required for the carbon thermal reduction reaction, promoting the directional growth of SiC whiskers. Based on these findings, an ablation mechanism is proposed.随着高超声速航天技术的发展，对固体火箭发动机的热防护提出了更大的挑战，绝缘材料的烧蚀性能需要进一步提高。碳纳米管作为一种新型的补强纳米填料，在srm运行过程中容易与工作气体中的氧化组分发生反应，限制了其优异的性能。在本研究中，我们建议在CNTs表面涂覆常用的补强填料SiO2，以抑制其氧化敏感性，并研究在基体中添加CNTs、SiO2和CNTs@SiO2对材料性能的影响。结果表明：CNTs@SiO2的加入显著提高了绝缘材料的抗烧蚀性能，M-@SiO2-2的线性烧蚀率比M-SiO2-2降低了56%；通过对材料抗氧化性能和烧蚀后炭层强度的分析，探讨了提高烧蚀性能的原因。通过高温管炉试验，研究了不同温度下炭层的组成和结构，发现CNTs@SiO2配方中的CNTs可以直接提供碳热还原反应所需的碳源，促进SiC晶须的定向生长。基于这些发现，提出了消融机制。A novel method for through-thickness reinforcement of laminated composites using discrete micro-polarization-induced fiber injection (DMFI) approachYihan Fu, Shuran Li, Mengze Li, Liang Cheng, Weidong Zhu, Yinglin Kedoi:10.1016/j.compscitech.2024.110912 采用离散微偏振诱导纤维注入（DMFI）方法对层合复合材料进行通厚增强Conventional through-thickness reinforcement methods for laminated composites, such as Z-pin, encounter issues with in-plane property degradation and complex fabrication processes. To achieve rapid and low-damage reinforcement, a novel approach using short-chopped carbon fibers (SCFs) to form a micron-diameter interlaminate structure has been proposed. This method employs a discrete micro-polarization-induced fiber injection (DMFI) technique, where polarized SCFs are electrostatically oriented and injected at high speeds into pre-formed holes in the laminates. The insertion process of SCFs was thoroughly investigated, with optimal interlaminate conditions determined using high-speed cameras and other equipment. The toughening mechanism of SCFs was explored through various characterization methods, including metallurgical microscopy. This innovative method offers several advantages over the traditional Z-pin reinforced method. Notably, present method eliminates the need for prefabrication of Z-pins and fully leverages the excellent mechanical properties of individual carbon fiber in short length. It provides superior interlaminar mechanical properties, achieving a 392 % improvement compared to the control group and a 15 % improvement compared to 0.1 mm Z-pin reinforcement at the same insertion volume fraction. Additionally, it has minimal impact on the in-plane properties of the laminates, with only a 3.6 % reduction in tensile strength and a 4.1 % reduction in compression strength. Furthermore, it is environmentally friendly, allowing for the recycling and reuse of waste SCFs.传统的层压复合材料的透厚增强方法，如Z-pin，遇到了面内性能退化和复杂的制造工艺的问题。为了实现快速和低损伤的增强，提出了一种使用短切碳纤维（SCFs）形成微米直径层间结构的新方法。该方法采用离散微极化诱导纤维注入（DMFI）技术，将极化的scf静电定向并高速注入层压板上预先形成的孔中。深入研究了SCFs的插入过程，并使用高速摄像机和其他设备确定了最佳层间条件。通过金相显微镜等多种表征方法探讨了SCFs的增韧机理。与传统的z针加固方法相比，这种创新方法具有几个优点。值得注意的是，该方法消除了预制z针的需要，并充分利用了短长度单个碳纤维的优异机械性能。它提供了优越的层间力学性能，与对照组相比，在相同的插入体积分数下，与0.1 mm Z-pin增强相比，提高了392%，提高了15%。此外，它对层压板的面内性能影响最小，抗拉强度仅降低3.6%，抗压强度仅降低4.1%。此外，它是环保的，可以回收和再利用废弃的SCFs。来源：复合材料力学仿真Composites FEM