今日更新：Composite Structures 2 篇，Composites Part A: Applied Science and Manufacturing 4 篇，Composites Part B: Engineering 1 篇，Composites Science and Technology 1 篇
Composite Structures
Influencing factors and sensitivity analysis for the fatigue of FRP wire based on the progressive fatigue damage model
Nani Bai, Hui Li, Chengming Lan, B.F. Spencer
doi:10.1016/j.compstruct.2024.117982
基于渐进疲劳损伤模型的玻璃钢线材疲劳影响因素及敏感性分析
FRP cables can experience degradation of their mechanical properties due to repetitive loading, resulting in increasing attention being devoted to their fatigue performance. This study aims to quantify the impact of the following four influencing factors on the fatigue behavior of FRP wire: (i) the applied maximum fatigue stress, (ii) interfacial shear strength, (iii) fiber volume fraction, and (iv) the Weibull shape parameter of the fiber fatigue strength coefficient. The recently developed progressive fatigue damage model (PFDM) is employed herein, and an adaptive block-by-block strategy is proposed to improve computational performance. The influences of the four factors on fatigue characteristics of FRP wire are illustrated using Monte Carlo simulation. Subsequently, a sensitivity analysis is performed for the fatigue behavior of FRP wire based on the linear regression approach, and Standardized Regression Coefficient is derived to rank the significance of the influencing factors. The following three indicators are selected to evaluate the sensitivities: (i) the fatigue life, (ii) the minimum normalized residual stiffness, and (iii) size of the critical damage cluster. Results show that the fatigue life and minimum normalized residual stiffness of FRP wire are most sensitive to the fiber volume fraction and Weibull shape parameter, respectively. Increasing fiber volume fraction can lead to longer fatigue life but results in more stiffness degradation before failure. A higher Weibull shape parameter leads to less stiffness degradation but results in a shorter fatigue life. Reducing the sensitivity of the FRP wire to cyclic degradation is best achieved by increasing the interfacial shear strength. This study can provide guidance for evaluation and optimization of the FRP wire fatigue behavior.
Guided wave resonance identification of interface delamination in bimaterial composites
Mikhail V. Golub, Artem A. Eremin, Evgeny V. Glushkov, Natalia V. Glushkova
doi:10.1016/j.compstruct.2024.117983
双材料复合材料界面分层的导波共振识别
Laminate composites are widely used in industrial applications due to their high material strength and efficiency. In such materials, impact loads can cause internal delaminations at the bonding interfaces between sublayers, which further growth during operation could lead to structural failure. Guided wave based non-destructive testing allows detecting such hidden delamination, which manifests itself in the wavefield disturbance at the obstacle vicinity. However, their sizing requires sophisticated post-processing of the acquired wave signals. In our previous studies, a method for sizing an internal strip-like crack in a homogeneous elastic plate has been developed and experimentally approved. The method is based on the numerical evaluation of the scattering resonance frequencies depending on the crack size, and their comparison with the experimentally obtained ones. In the present paper, we extend this approach to the case of dissimilar-material laminates. Numerical simulation and laser Doppler vibrometry measurements were carried out for bi-layer samples composed of various combinations of glued steel, aluminium, and glass sublayers with artificial strip-like delamination. The results obtained confirm the possibility of damage width estimation using the values of scattering resonance frequencies extracted from the signals acquired at the sample surface.
Composites Part A: Applied Science and Manufacturing
Recycled carbon fiber reinforced composites: Enhancing mechanical properties through co-functionalization of carbon nanotube-bonded microfibrillated cellulose
Mahyar Fazeli, Siddharth Jayaprakash, Hossein Baniasadi, Roozbeh Abidnejad, Juha Lipponen
doi:10.1016/j.compositesa.2024.108097
再生碳纤维增强复合材料：通过碳纳米管结合微纤化纤维素的共官能化提高机械性能
The imperative challenge of repurposing recycled carbon fiber (rCF) in composite structures, due to its cost-effectiveness and eco-friendly attributes, has spurred innovative research. This study introduces a scalable processing technique, integrating carbon nanotube (CNT)-bonded microfibrillated cellulose (MFC) onto randomly oriented rCF mats, focusing on enhancing mechanical properties. Employing electrophoretic deposition (EPD), rCF surfaces are effectively functionalized with CNT/MFC, probed through X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Modified fiber surfaces exhibit reduced contact angles, indicating improved wettability. Epoxy-based composites, fabricated via vacuum infusion, show up to 32% and 27% improvements in tensile and flexural strength. Dynamic mechanical analysis (DMA) confirms elevated storage modulus and energy dissipation capability. SEM analysis of fracture surfaces illustrates robust adhesion between coated fibers and the matrix, supporting the proposed approach's efficacy. This study unveils an innovative pathway to enhance recycled carbon fiber composite properties, extending their application potential in diverse engineering domains.
Comprehensive assessment of hybrid GFRP-Graphite filler using modified complex Arcan fixture: Experimental and simulation approach
Daffa Alandro, Ariyana Dwiputra Nugraha, Iosif Azurra Maulana, Alvin Dio Nugroho, Wahyu Erlangga, Muhammad Akhsin Muflikhun
doi:10.1016/j.compositesa.2024.108094
使用改良的复杂 Arcan 夹具对 GFRP-石墨混合填料进行综合评估：实验和模拟方法
A detailed understanding of the interlaminar fracture, intralaminar fracture, and translaminar fracture progression of GFRP was studied using a complex Arcan fixture. A loading angle of 0o to 150o was successfully tested with detailed characteristics evaluated on 0o, 45o, and 90o. The different behaviors of the specimens were recorded in shear, tensile shear, and tensile stress. At these angles, the specimens reach 9.13, 36.00, and 51.64 MPa, while reaching the shear strain of 0.311, 0.153, and 0.046 με, respectively. FEM analysis was also incorporated to obtain the fracture behavior and stress distribution in the notch. Mises stress was 9.754 MPa, close to the average of 9.519 MPa from experiments. Adding graphite filler to the composite increases the composite's shear stress but reduced shear strain. 0.5% graphite filler became the optimal ratio by making the shear stress reach 16.94 MPa with a minimum decrease in shear strain with 0.293 με.
Enhancing Interlaminar Bonding Quality Estimation in Laser-Assisted Fiber Placement of CF/PEKK Composites: A Correction Factor Approach for Improved Prediction of Intimate Contact
Ali Barzegar, Sasan Karimi, Hatice S. Sas, Mehmet Yildiz
doi:10.1016/j.compositesa.2024.108095
在激光辅助纤维铺放 CF/PEKK 复合材料中提高层间粘合质量估计：改进亲密接触预测的修正系数方法
This study introduces an innovative Modified Mantell and Springer (MMS) model to more accurately assess degree of intimate contact with improved accuracy, which also significantly enhances the subsequent degree of healing estimation and enables the presentation of an improved degree of bonding. Process parameters such as placement speed and consolidation forces, and fiber orientation are identified as key determinants of bonding quality. Lower placement speeds and higher consolidation forces are linked to increased healing and intimate contact between layers, crucial for achieving desired degree of bonding. The MMS model proves effective in capturing the influence of fiber orientation, revealing that [0°/0°] orientation exhibits superior bonding strength. Validation through T-peel tests provides tangible evidence of the model's precision, aligning fracture surface observations with model predictions. This research contributes to a comprehensive understanding and prediction of composite bonding quality, offering valuable insights for optimizing manufacturing processes and enhancing the mechanical performance of composites manufactured with Laser-Assisted Fiber Placement (LAFP).
本研究引入了一种创新的修正曼特尔和斯普林格（MMS）模型，以更高的精度更准确地评估亲密接触程度，这也大大提高了后续愈合程度的估算，使粘合程度得到改善。贴片速度、固结力和纤维取向等工艺参数被认为是决定粘合质量的关键因素。较低的贴片速度和较高的固结力会增加愈合和层间的亲密接触，这对达到理想的粘合度至关重要。事实证明，MMS 模型能有效捕捉纤维取向的影响，揭示出[0°/0°]取向具有更高的粘合强度。通过 T 型剥离试验验证了模型的精确性，使断裂面观察结果与模型预测结果一致。这项研究有助于全面了解和预测复合材料的粘合质量，为优化制造工艺和提高使用激光辅助纤维铺放（LAFP）制造的复合材料的机械性能提供了宝贵的见解。
Multifunctional green composites based on plasma-activated and GO-coated dwarf palm fibers
Andrea Maio, Roberto Scaffaro
doi:10.1016/j.compositesa.2024.108096
基于等离子激活和 GO 涂层矮棕榈纤维的多功能绿色复合材料
In this work, we propose a green method for decorating natural fibers derived from dwarf palm waste with graphene oxide (GO) sheets. In detail, plasma-treatment was used to activate fiber surface for the subsequent GO-coating, which was performed in water. Poly(butylene adipate-co-terephthalate) (PBAT)-based composites incorporating 50% of either raw, plasma-modified or hybrid fibers were prepared by compression moulding and thoroughly analysed to investigate the processing-structure-properties relationships of these systems. The outcomes reveal that combining plasma treatment and GO coating enables fabricating green composites with significantly improved mechanical performance (stiffness and tensile strength increments of up to 500% and 300%, respectively) and electrical conductivity on the order of 10-6 S/m.
在这项工作中，我们提出了一种用氧化石墨烯（GO）薄片装饰从矮棕榈废料中提取的天然纤维的绿色方法。具体来说，我们使用等离子体处理来活化纤维表面，以便随后在水中进行 GO 涂层。通过压缩模塑法制备了含有 50% 未加工纤维、等离子体改性纤维或混合纤维的聚（己二酸丁二醇酯-对苯二甲酸酯）（PBAT）基复合材料，并对其进行了深入分析，以研究这些系统的加工-结构-性能关系。研究结果表明，将等离子处理与 GO 涂层相结合可制造出机械性能显著提高（刚度和拉伸强度分别提高了 500% 和 300%）、导电率达到 10-6 S/m 量级的绿色复合材料。
Composites Part B: Engineering
Achieving RCS reduction via scattering and absorption mechanisms using a chessboard structured composite
Based on the concept of periodic structural unit, a chessboard structured composite composed of quartz fiber and carbon fiber is proposed in this study for reducing radar cross section (RCS). An automated manufacture technique – stitching was applied in the unit construction, showing the great potential on mass production and low cost. The design of RCS reduction adopts the cooperative mechanisms of absorption and scattering. The results show that the RCS reduction of chessboard structured composite is below −10dB in the range of 8.9–15.1GHz, and the peak value of the RCS reduction can reach −23dB. By simulating the different unit parameters of chessboard regions, the optimal parameters are obtained. Region 0 and region 1 present different energy distributions and a phase difference of 180° ± 78°, which is an important reason for the scattering mechanism of chessboard structured composite. To further explore the mechanisms of scattering and absorption, the electric field, magnetic field and power loss of the two regions at the absorption peak are simulated. According to the absorption energy distribution, it can be inferred that impedance matching plays an important role in the absorption mechanism. Moreover, the oblique incidence test and simulation prove the good angular stability of chessboard structured composite. The good mechanical properties of chessboard structured composite demonstrate the great potential of structure-function integration. Furthermore, the mass production capacity of the proposed composite gives the broad prospects in practical engineering application.
Evaluating the loading rate dependency of mode I delamination for composite laminates at different temperatures
Junchao Cao, Bin Jiang, Zhouyi Li, Zhilong Dang, Chao Zhang
doi:10.1016/j.compscitech.2024.110505
评估不同温度下复合材料层压板模式 I 分层的加载速率相关性
This study presents an investigation on the influence of loading rate and temperature on mode I interlaminar fracture toughness of unidirectional composite laminates. An analytical model was developed to describe the temperature- and loading rate-dependent fracture toughness, and a loading rate coefficient m was defined to evaluate the rate dependency. Quasi-static and dynamic double cantilever beam (DCB) tests were conducted at various temperatures from −20 to 110 °C. A dual electromagnetic Hopkinson bar was employed to perform dynamic tests under loading rates of 15 and 24 m/s to achieve pure mode I delamination. The experimental results show that the fracture toughness exhibits an obvious positive loading rate sensitivity at all temperatures, whereas the loading rate coefficient m shows two different trends with temperature indicating different loading rate dependency. Fractography observations reveal an obvious transition in the dominant failure mechanism at low temperatures from fiber/matrix interface debonding under quasi-static conditions to brittle fracture of matrix under dynamic conditions. However, both the quasi-static and dynamic delamination surfaces exhibit multiple failure modes at high temperatures. It is reasonable to deduce that the effect of temperature and loading rate can be attributed to the nature of matrix, the bonding between fiber and matrix.
本研究探讨了加载速率和温度对单向复合材料层压板的模式 I 层间断裂韧性的影响。建立了一个分析模型来描述与温度和加载速率相关的断裂韧性，并定义了加载速率系数 m 来评估速率相关性。在 -20 至 110 °C 的不同温度下进行了准静态和动态双悬臂梁 (DCB) 试验。采用双电磁霍普金森杆在 15 和 24 m/s 的加载速率下进行动态测试，以实现纯 I 模式分层。实验结果表明，在所有温度下，断裂韧性都表现出明显的正加载速率敏感性，而加载速率系数 m 随温度的变化呈现出两种不同的趋势，表明了不同的加载速率依赖性。碎裂图观察结果表明，在低温条件下，主要的破坏机制从准静态条件下的纤维/基体界面脱粘明显过渡到动态条件下的基体脆性断裂。然而，准静态和动态脱层表面在高温下都表现出多种失效模式。由此可以合理地推断出，温度和加载速率的影响可归因于基体的性质、纤维与基体之间的粘合。
