今日更新：Composite Structures 3 篇，Composites Science and Technology 3 篇Composite StructuresStiffness assessment of the laminate recovered from end-of-life wind turbine bladeŁ. Pyrzowski, A. Sabik, J. Kluska, J. Zembrzuskidoi:10.1016/j.compstruct.2024.118439风机叶片报废回收层压板刚度评估In the paper the stiffness parameters of the laminate recovered from an aerodynamic shell of a decommissioned wind turbine blade are evaluated. The aim of the work is to assess selected methods for identifying material data, as well as to estimate the level of stiffness degradation during turbine operation. Several practical identification methods are presented and compared. Two concepts of a single laminate layer are considered, global and local. The global concept assumes that the equivalent layer of the laminate is a system of three physical layers of a single triaxial fabric. The local concept takes into account all physical layers of the laminate. The material parameters of the global layer are identified and validated in experimental tests. Data for individual physical layers are determined by inverse analysis and the rule of mixtures. The compliance of the results obtained allows one to conclude that the stiffness of the material did not degrade significantly during the operation period. The stiffness parameters of the laminate have shown that the tested material is still very attractive for structural purposes.本文对某风力发电机组叶片气动壳体回收的层压板的刚度参数进行了计算。这项工作的目的是评估识别材料数据的选定方法，以及估计涡轮机运行期间刚度退化的水平。提出并比较了几种实用的识别方法。考虑了单层压板层的两个概念，全局和局部。整体概念假定层压板的等效层是由单个三轴织物的三个物理层组成的系统。局部概念考虑了层压板的所有物理层。通过实验验证了整体层的材料参数。单个物理层的数据由逆分析和混合规则确定。所得结果的一致性允许人们得出结论，即材料的刚度在操作期间没有显着退化。层压板的刚度参数表明，测试材料仍然是非常有吸引力的结构目的。A topology and sizing optimisation method for lightweight sandwich structures subject to dynamic and static constraintsJohan Larsson, Peter Göransson, Per Wennhagedoi:10.1016/j.compstruct.2024.118442动态和静态约束下轻质夹层结构的拓扑和尺寸优化方法A static-dynamic topology-sizing optimisation method is presented. The solution is based on a sequential Mixed-Integer Linear Programming solution and aims to minimise the mass of a structure subjected to concurrent constraints on static and dynamic response. It is shown that the classical problem of the dynamics of lightweight sandwich structures may be mitigated through core topology and face sheet thickness combinations, retaining the static load carrying capacity while presenting stringent dynamic properties at a low mass penalty. A numerical example, in the form of a load carrying sandwich beam which is excited at different frequencies, is used to demonstrate the method.提出了一种静态-动态拓扑尺寸优化方法。该解决方案基于顺序混合整数线性规划解决方案，旨在最大限度地减少结构在静态和动态响应同时约束下的质量。研究结果表明，通过芯层拓扑结构和面板厚度组合可以缓解轻质夹层结构的经典动力学问题，在保持静态承载能力的同时，在低质量惩罚下表现出严格的动态性能。最后以受不同频率激励的夹芯梁为算例，对该方法进行了验证。Fatigue damage analysis and life prediction of 3D braided SiC/SiC composites with multi-scale approachJiangbo Han, Liming Lei, Shanhua Liu, Jincao Zhangdoi:10.1016/j.compstruct.2024.118447基于多尺度方法的三维编织SiC/SiC复合材料疲劳损伤分析与寿命预测Due to the high cost and complex operation of fatigue tests, a multi-scale fatigue damage analysis and life prediction method for 3D braided SiC/SiC composites is proposed in this paper. In this method, the fatigue behavior of the interface is characterized by the cyclic cohesive zone model (CCZM), which is based on the cohesive zone model (CZM) obtained from molecular dynamics (MD) simulations. The fatigue damage evolution of the yarn and matrix is described by a continuous damage model (CDM) along with an exponential damage-cycle number (D-n) relationship. Geometrically, a representative volume element (RVE) model consisting of a zero-thickness interface, yarn and matrix is constructed. The fatigue analysis is carried out by the software ABAQUS, in which the fatigue life of 3D braided SiC/SiC composites at different fatigue loading factors is predicted, and the maximum fatigue stress versus the number of cycles (S-N) curves are plotted. When the maximum fatigue stress is 18% of the tensile strength, the fatigue life prediction accuracy of the proposed method is within 2.2 times error band, which demonstrates the effectiveness and reliability on the proposed method in this paper. This work provides an innovative perspective for fatigue damage and life prediction to braided SiC/SiC composites.针对三维编织SiC/SiC复合材料疲劳试验成本高、操作复杂的问题，提出了一种三维编织SiC/SiC复合材料多尺度疲劳损伤分析及寿命预测方法。该方法采用基于分子动力学(MD)模拟得到的黏结区模型(CZM)的循环黏结区模型(CCZM)来表征界面的疲劳行为。采用连续损伤模型(CDM)描述了纱线和基体的疲劳损伤演化过程，损伤周期数呈指数关系(D-n)。几何上，构造了由零厚度界面、纱线和基体组成的具有代表性的体积元模型。利用ABAQUS软件进行疲劳分析，预测了三维编织SiC/SiC复合材料在不同疲劳载荷下的疲劳寿命，绘制了最大疲劳应力与循环次数的S-N曲线。当最大疲劳应力为抗拉强度的18%时，所提方法的疲劳寿命预测精度在2.2倍误差范围内，验证了所提方法的有效性和可靠性。本研究为编织SiC/SiC复合材料的疲劳损伤和寿命预测提供了一个创新的视角。Composites Science and TechnologyFabric-based capacitive pressure sensors for porous four-phase composites with high sensitivity and wide linearity rangeYuan Xiao, Dongyuan Guo, Leipeng Yang, Yao Tong, Xianjun Wu, Yuping Wangdoi:10.1016/j.compscitech.2024.110794 具有高灵敏度和宽线性范围的多孔四相复合材料织物电容式压力传感器Fabric-based capacitive pressure sensors have attracted wide attention in smart textiles due to their high sensitivity and fast response advantages. However, there are problems in the optimization study of its performance, such as the difficulty of combining the sensor with fabric and the mutual restriction of high sensitivity and wide linear range. This paper reports a fabric-based capacitive pressure sensor with porous four-phase composites. Microdroplet spraying and liquid-phase reductive deposition techniques were used to spray-print form silver electrodes on a fabric substrate. Meanwhile,multi-walled carbon nanotubes/carbon black/barium titanate-polydimethylsiloxane composite films (MWCNTs/CB/BT-PDMS) with porous structure were obtained as the dielectric layer by using a solution co-mingled casting and sacrificial template method. Benefitting from the high conductivity of the fabric silver electrode, the porous structure of the dielectric layer, and the synergistic effect between the fillers resulted in a sensor with a sensitivity of up to 2.28 kPa−1 (R2 = 0.995) over a wide linear range from 0 to 50 kPa, with the product of the two being 114. In addition, the sensor can accurately monitor various physiological activities of the human body (e.g., respiration monitoring, expression recognition, and joint movement), showing its promising applications in wearable electronic devices.基于织物的电容式压力传感器以其灵敏度高、响应速度快等优点在智能纺织品领域受到广泛关注。但其性能优化研究中存在传感器与织物不易结合、高灵敏度与宽线性范围相互制约等问题。本文报道了一种基于织物的多孔四相复合材料电容式压力传感器。采用微滴喷涂和液相还原沉积技术在织物衬底上进行了银电极的喷印。同时，采用溶液共混铸造和牺牲模板法制备了多孔结构的多壁碳纳米管/炭黑/钛酸钡-聚二甲基硅氧烷复合薄膜(MWCNTs/CB/BT-PDMS)作为介质层。得益于织物银电极的高导电性，介质层的多孔结构以及填料之间的协同效应，在0 ~ 50 kPa的宽线性范围内，传感器的灵敏度高达2.28 kPa−1 (R2 = 0.995)，两者的乘积为114。此外，该传感器可以准确监测人体的各种生理活动(如呼吸监测、表情识别、关节运动)，在可穿戴电子设备中具有广阔的应用前景。Carbon contrast agents for terahertz spectroscopic NDT of impacted glass fibre reinforced plasticsOzan Can Zehni, Yury Malevich, Ali Kandemir, Cristina Valles, Mark A. Bissett, Coskun Kocabas, Ian A. Kinlochdoi:10.1016/j.compscitech.2024.110795 冲击玻璃纤维增强塑料太赫兹光谱无损检测用碳造影剂Impact damage poses a significant challenge for composite materials since it is often subsurface and hard to detect, necessitating effective assessment approaches. Traditional NDT methods face challenges in identifying this specific type of damage. In this study, a departure from traditional NDT approaches was taken by utilizing THz spectroscopy to detect impact damage. Three different lay-ups of GFRP laminates were studied; GFRP with non-woven carbon fibre veil, GFRP coated with MWCNTs, and plain GFRP. Impact tests were conducted ranging from 5, 12 and 20 J in energy and 2D images were then acquired It was found that the inclusion of the MWCNTs and carbon veil gave superior image contrast compared to plain GFRP. Furthermore, the damaged area observed in the images increased with impact energy across all configurations. The outcomes derived from THz spectroscopy were benchmarked against those from ultrasound testing. THz spectroscopy demonstrates greater promise as a highly effective technique for detecting impact damage using carbon materials, offering advantages over traditional NDT methods due to its distinct wavelength, portability, non-contact capability, capacity to depict fibre alignment, lack of additional calibration specimens and coupling agents, and its ability to partially uncover the scope of impact damage.由于冲击损伤通常发生在地下且难以检测，因此需要有效的评估方法，因此对复合材料构成了重大挑战。传统的无损检测方法在识别这种特殊类型的损伤方面面临挑战。在这项研究中，利用太赫兹光谱来检测冲击损伤，与传统的无损检测方法不同。研究了三种不同铺层方式的玻璃钢复合材料;GFRP与无纺布碳纤维面纱，GFRP涂层mwcnt和普通GFRP。在5、12和20 J的能量范围内进行了冲击试验，然后获得了2D图像。结果发现，与普通GFRP相比，MWCNTs和碳膜的包含具有更好的图像对比度。此外，在所有构型中，图像中观察到的损伤区域随着冲击能量的增加而增加。太赫兹光谱学得出的结果与超声波测试的结果进行了基准比较。太赫兹光谱学作为一种使用碳材料检测冲击损伤的高效技术显示出更大的前景，由于其独特的波长，便携性，非接触能力，描述纤维排列的能力，缺乏额外的校准样品和偶联剂，以及部分揭示冲击损伤范围的能力，提供了优于传统无损检测方法的优势。Non-contact Defect Imaging of Carbon Fiber Composites using Laser Excited Acoustic ShearographyZi Wen Tham, Santhakumar Sampath, Yi Fan Chen, Bisma Mutiargo, Lei Zhangdoi:10.1016/j.compscitech.2024.110796 碳纤维复合材料非接触缺陷激光激发声剪切成像The performance of carbon fiber reinforced polymer (CFRP) composites is significantly affected by the presence of subsurface defects, which originate from manufacturing processes or during operations. Although many non-destructive testing (NDT) methods have been employed to inspect CFRP materials and structures, the existing techniques are often time-consuming and sometimes require contact measurement. This paper presents a non-contact and rapid inspection method utilizing laser-excited acoustic shearography to detect subsurface defects in CFRP composites. In this method, a pulsed nanosecond laser is used to generate ultrasonic waves through thermoacoustic effect, and a shearography sensor is used to image the full-field wave-defect interactions. It is found that the proposed method can efficiently image various subsurface defect sizes in a non-contact way. The identified defects were validated through comparison with X-ray computed tomography (XCT).碳纤维增强聚合物(CFRP)复合材料的性能受到制造过程或操作过程中存在的表面缺陷的显著影响。尽管许多无损检测(NDT)方法已被用于检测CFRP材料和结构，但现有的技术往往是耗时的，有时需要接触测量。提出了一种利用激光激发声剪切成像检测CFRP复合材料亚表面缺陷的非接触快速检测方法。该方法利用脉冲纳秒激光通过热声效应产生超声波，利用剪切成像传感器对波与缺陷的全场相互作用进行成像。实验结果表明，该方法可以有效地对不同尺寸的亚表面缺陷进行非接触成像。通过与x射线计算机断层扫描(XCT)的比较，验证了所识别的缺陷。来源：复合材料力学仿真Composites FEM
