今日更新:Composites Part A: Applied Science and Manufacturing 5 篇,Composites Science and Technology 1 篇
Composites Part A: Applied Science and Manufacturing
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.
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.
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.
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.
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.
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.