今日更新:Composites Part A: Applied Science and Manufacturing 5 篇,Composites Science and Technology 1 篇
Continuous tow shearing for the automated manufacture of defect-free complex 3D geometry composite parts
Edwin Rosario Gabriel, Michelle Rautmann, Byung Chul Kim
doi:10.1016/j.compositesa.2024.108212
连续剪切用于无缺陷复杂三维几何复合材料零件的自动化制造
It has always been challenging to manufacture a composite structure with complex geometry using automated fibre placement (AFP) process. The tool surface is difficult to be tessellated using fibre tapes with a finite width, without producing gaps and overlaps, and fibre steering along non-geodesic fibre paths produces various defects such as tape buckling and pull-up. In this work, a defect-free fibre-steering process on a complex surface was demonstrated by realising the continuous tow shearing (CTS) process in three dimensions. A new head control algorithm was developed, which defines the head orientations and trajectories based on the pin-jointed net model to manipulate the fibre tow using both in-plane shear and out-of-plane twisting deformations. Fibre steering process utilising this new algorithm was tested on a doubly-curved surface, using an industrial robot arm equipped with a CTS prototype head, and its layup quality and accuracy were assessed by using a three-dimensional laser profile scanner. An experimental comparison with the conventional AFP process showed that the new control algorithm enables defect-free fibre steering on complex 3D surfaces allowing for simplifying the design and analysis of novel composite structures.
使用自动纤维铺放(AFP)工艺制造具有复杂几何形状的复合材料结构一直是一个挑战。使用有限宽度的纤维带很难在不产生间隙和重叠的情况下对工具表面进行镶嵌,并且纤维沿着非测地线纤维路径转向会产生各种缺陷,例如胶带屈曲和拉起。在这项工作中,通过在三维空间中实现连续剪切(CTS)过程,证明了在复杂表面上无缺陷的纤维转向过程。提出了一种新的头部控制算法,该算法基于针节网模型定义头部方向和轨迹,利用面内剪切和面外扭转变形对纤维束进行控制。利用该算法在双曲面上对光纤转向过程进行了测试,并使用配备CTS原型头的工业机械臂进行了测试,并使用三维激光轮廓扫描仪对其铺层质量和精度进行了评估。与传统AFP过程的实验比较表明,新的控制算法可以在复杂的3D表面上实现无缺陷的纤维转向,从而简化了新型复合材料结构的设计和分析。
Quest for environmentally sustainable materials: A case for animal-based fillers and fibers in polymeric biocomposites
Segun I. Talabi, Sikiru O. Ismail, Emmanuel I. Akpan, Ahmed Arabi Hassen
doi:10.1016/j.compositesa.2024.108216
对环境可持续材料的探索:高分子生物复合材料中动物基填料和纤维的案例
This review explores the potential of animal-based fillers and fibers as eco-friendly alternatives to conventional synthetic ones. Examining materials such as wool, silk, feather, hair and beak, the review elucidates their chemistry, structure, properties and sources, emphasizing biodegradability and renewability. It also discusses the compatibility of these materials with polymer matrices and their mechanical, acoustic and thermal performances. The review critically analyzes environmental and ethical implications, presenting challenges and opportunities in the emerging field. By addressing ecological and performance aspects, it contributes to global efforts in fostering sustainability in materials science. Future research to address gaps and enhance the design, manufacture and application of animal-based reinforcements in various industries are clearly outlined at the end of the review.
这篇综述探讨了动物基填料和纤维作为传统合成材料的环保替代品的潜力。以羊毛、蚕丝、羽毛、毛发和鸟喙等材料为例,阐述了它们的化学、结构、性能和来源,强调了它们的可生物降解性和可再生性。还讨论了这些材料与聚合物基体的相容性及其力学、声学和热性能。该评论批判性地分析了环境和伦理影响,提出了新兴领域的挑战和机遇。通过解决生态和性能方面的问题,它有助于促进材料科学的可持续性的全球努力。在回顾的最后,明确概述了未来的研究,以解决差距和加强动物基增强材料在各个行业的设计、制造和应用。
Modeling of progressive high-cycle fatigue in composite laminates accounting for local stress ratios
P. Hofman, F.P. van der Meer, L.J. Sluys
doi:10.1016/j.compositesa.2024.108219
考虑局部应力比的复合材料层合板进阶高周疲劳建模
A numerical framework for simulating progressive failure under high-cycle fatigue loading is validated against experiments of composite quasi-isotropic open-hole laminates. Transverse matrix cracking and delamination are modeled with a mixed-mode fatigue cohesive zone model, covering crack initiation and propagation. Furthermore, XFEM is used for simulating transverse matrix cracks and splits at arbitrary locations. An adaptive cycle jump approach is employed for efficiently simulating high-cycle fatigue while accounting for local stress ratio variations in the presence of thermal residual stresses. The cycle jump scheme is integrated in the XFEM framework, where the local stress ratio is used to determine the insertion of cracks and to propagate fatigue damage. The fatigue cohesive zone model is based on S-N curves and requires static material properties and only a few fatigue parameters, calibrated on simple fracture testing specimens. The simulations demonstrate a good correspondence with experiments in terms of fatigue life and damage evolution.
通过对复合材料准各向同性开孔层合板的实验,验证了该数值框架在高周疲劳载荷作用下的渐进破坏模拟。横向基体开裂和分层采用混合模式疲劳内聚区模型,涵盖裂纹的起裂和扩展。此外,XFEM还用于模拟任意位置的横向基体裂纹和开裂。在考虑热残余应力存在时局部应力比变化的情况下,采用自适应循环跳变方法有效地模拟了高周疲劳。在XFEM框架中集成了循环跳变方案,利用局部应力比确定裂纹的插入和疲劳损伤的扩展。疲劳黏聚区模型基于S-N曲线,只需要材料的静态性能和少量的疲劳参数,在简单的断裂试样上进行校准。在疲劳寿命和损伤演化方面,模拟结果与实验结果吻合较好。
Contactless and nondestructive evaluation of residual stress distribution in modified and pure HDPE materials using a novel terahertz method and line-scan thermographic technique
Pengfei Zhu, Hai Zhang, Carlo Santulli, Stefano Sfarra, Rubén Usamentiaga, Vladimir P. Vavilov, Xavier Maldague
doi:10.1016/j.compositesa.2024.108220
使用新型太赫兹方法和线扫描热成像技术对改性和纯HDPE材料的残余应力分布进行非接触无损评估
Optical-stress properties were always studied at the elastic stage and at wavelengths shorter than terahertz (THz) radiation. Until present, the relationship between plastic strain and refractive index has not been fully understood. In this work, a novel THz method and line-scan thermographic technique are used for quantitative evaluation of the residual stress in the pure HDPE, as well as in the HDPE mixed with 5% by weight of wastepaper plus 5% by weight of chopped basalt as fillers. A new theory considering both influences from the sample thickness and the refractive index difference is proposed, thus allowing to improve the measurement accuracy. For the first time, the stress-optic constant and thermal diffusivity have been applied to characterize the residual stress.. The experiments suggest that, after stretching, the initial isotropic material transits into a material with highly anisotropic optical properties in THz band. This observation is useful when describing the conventional bi-refringence phenomenon. Finally, the residual stress distribution was calculated based on the proposed techniques.
光应力特性一直是在弹性阶段和波长短于太赫兹(THz)辐射下研究的。到目前为止,塑性应变和折射率之间的关系还没有完全了解。在这项工作中,使用了一种新的太赫兹方法和线扫描热成像技术来定量评估纯HDPE中的残余应力,以及以5%重量的废纸和5%重量的切碎玄武岩作为填料混合的HDPE中的残余应力。提出了一种同时考虑样品厚度和折射率差影响的新理论,从而提高了测量精度。首次将应力光学常数和热扩散系数用于表征残余应力。实验表明,初始各向同性材料经过拉伸后,在太赫兹波段跃迁为具有高度各向异性光学特性的材料。这个观察结果在描述传统的双折射现象时是有用的。最后,根据所提出的方法计算了残余应力分布。
Nonlinear electrical conductivity characteristics under high impulse current and applications to lightning strike damage simulation for CFRP laminates
Yu FUJISAWA, Takumi SATO, Yoshiyasu HIRANO, Shintaro KAMIYAMA, Toshio OGASAWARA
doi:10.1016/j.compositesa.2024.108230
高冲击电流下的非线性电导率特性及其在CFRP复合材料雷击损伤模拟中的应用
This experimental investigation assessed conductive properties of quasi-isotropic CFRP laminates in the thickness direction under high impulse current and clarified the properties’ effects on lightning damage behaviours. For CFRP laminates with interleaf resin layers (T800/3900-2B), experiments confirmed that conductivity in the thickness direction increases irreversibly with applied impulse current (approx. 5.3 kA, approx. 3.2 kV). However, the conductivity of CFRP laminates without interleaf resin layers (T800/2592) changed little during testing. Nonlinear conductive behaviour was applied to lightning strike damage numerical simulations using a coupled thermal–electrical analysis and heat transfer analysis. For numerical analyses, shape and dimensional changes of the applied current on the specimen surface were considered based on high-speed observations made during simulated lightning strike testing. The pyrolysis region calculated using damage analysis agrees well with experimentally obtained results when considering the potential gradient dependence of conductivity: better agreement was obtained than when calculated under a constant value.
实验研究了高冲击电流下准各向同性CFRP复合材料在厚度方向上的导电性能,并阐明了其导电性能对雷击损伤行为的影响。对于具有夹层树脂层的CFRP层压板(T800/3900-2B),实验证实,随着施加脉冲电流(约为1),在厚度方向上的电导率不可逆地增加。约5.3 kA。 3.2 kV)。而没有夹层树脂层的CFRP复合材料(T800/2592)在测试过程中电导率变化不大。采用热电耦合分析和传热耦合分析方法,将非线性导电特性应用于雷击损伤数值模拟。在数值分析中,基于模拟雷击试验期间的高速观测,考虑了施加在试样表面的电流的形状和尺寸变化。当考虑电导率的电位梯度依赖性时,损伤分析计算的热解区域与实验结果吻合较好,比在恒定值下计算的结果吻合得更好。
Preparation processes and thermal conductivities of magnetic field- and torsional vibration-induced superoriented carbon fiber composites
Chenhui Liu, Zhi Liu, Yu Wang, Meiping Song, Jiancheng Guo, Xiaoqing Yin, Xueping Gao, Bo Zhu, XiaoMin Yuan
doi:10.1016/j.compscitech.2024.110617
磁场和扭转振动诱导超取向碳纤维复合材料的制备工艺和热导率
With the advancement of semiconductor technology, advanced electronic devices have become increasingly efficient, highly integrated and multifunctional, producing a large amount of heat during operation, thus decreasing the device efficiency and increasing the requirements for thermal interface materials. The use of a magnetic field to prepare pitch-based carbon fibers (CFs) with ultrahigh axial thermal conductivities and aspect ratios is a promising method for preparing thermal interface materials. However, past methods are not adequately simple or effective. Herein, we propose a simple, efficient method for preparing a novel thermally conductive CF interface material with a superoriented and closely arranged structure. The thermal conductivity of the vertical plane can reach 82.026 Wm-1K-1, which is higher than that of many other alloys. During the experiment, we prove that the torsional vibration of the vibrating plate can greatly resolve the issue of powder bridging generated during preparation. In addition, we discover and explain the heat return conduction phenomenon through numerical simulation. Our innovative preparation process and our analysis of thermal conduction can provide a new method and unique view for the design of thermal interface materials.
随着半导体技术的进步,先进电子器件的效率越来越高,集成度越来越高,功能越来越多,在运行过程中会产生大量的热量,从而降低了器件效率,对热界面材料的要求也越来越高。利用磁场制备具有超高轴向导热系数和纵横比的沥青基碳纤维(CFs)是一种很有前途的热界面材料制备方法。然而,过去的方法不够简单或有效。在此,我们提出了一种简单、有效的方法来制备一种具有超取向和紧密排列结构的新型导热CF界面材料。垂直平面导热系数可达82.026 Wm-1K-1,高于许多其他合金。在实验中,我们证明了振动板的扭转振动可以极大地解决制备过程中产生的粉末桥接问题。此外,我们还通过数值模拟发现并解释了热传导现象。我们创新的制备工艺和对热传导的分析可以为热界面材料的设计提供一种新的方法和独特的视角。