今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Composite Structures
Dynamic crushing performance of foam-filled periodic hybrid cellular structures
Ting Liu, Changhai Chen, Yuansheng Cheng
doi:10.1016/j.compstruct.2024.117952
泡沫填充周期性混合蜂窝结构的动态挤压性能
To achieve excellent dynamic crushing performance, an attractive foam-filled periodic hybrid cellular (F-PHC) structure containing both hexagonal and re-entrant cells was designed and fabricated. Dynamic crushing experiments for foam-filled PHC structures were carried out using a direct impact Kolsky bar testing system. Reliable numerical simulations using both finite element method and smoothed particle hydrodynamics method were developed to analyze the dynamic crushing responses of F-PHC structures in the full range of deformation processes. Effects of inertia, strain-rate sensitivity, cell number, and impact velocity were evaluated. The results show that the dynamic plateau stresses of periodic hybrid cellular structures can be substantially enhanced by filling foams. The dynamic crushing response of F-PHC structure is very susceptible to impact velocity due to inertia effect. Compared with foam-filled hexagonal honeycomb and foam-filled re-entrant honeycomb structures, F-PHC structures exhibited superior dynamic crushing performances, including smoother and longer dynamic plateau stresses, more uniform deformation distributions, and much more stable deformation processes. Moreover, F-PHC structures exhibited much lower dynamic initial peak stresses at the rear face. This study provides a fascinating design idea and shines light on attractive F-PHC structures with a promising application prospect in the field of impact protection.
The kerf taper and cutting front drag are crucial factors limiting the abrasive waterjet (AWJ) machining of ultra-thick CFRP laminates. Therefore, this study investigated the variation patterns of kerf width and maximum cutting front drag with process parameters and established predictive models. The models accurately predicted kerf entrance width, kerf exit width, and maximum cutting front drag with R-squares of 0.9881, 0.9761, and 0.9791. Moreover, the influence of the key kinematic parameter of complex structure manufacturing - the jet impact angle on the kerf profile was analyzed from a geometric analysis. A numerical regression approach was employed to derive an energy dissipation function for CFRP laminate processing. A semi-analytical mathematical model was established based on energy balance theory. Under arbitrary jet impact angle, the kerf profiles on both sides are predicted with R-square of 0.9455 and 0.9525 respectively, and the cutting front drag profile is predicted with R-square of 0.9078.
切口锥度和切割前阻力是限制加砂水刀(AWJ)加工超厚 CFRP 层压板的关键因素。因此,本研究调查了切口宽度和最大切割前阻力随工艺参数的变化规律,并建立了预测模型。模型准确预测了切口入口宽度、切口出口宽度和最大切削前阻力,R-squares 分别为 0.9881、0.9761 和 0.9791。此外,还从几何分析的角度分析了复杂结构制造的关键运动参数--射流冲击角对切口轮廓的影响。采用数值回归方法得出了 CFRP 层压板加工的能量耗散函数。根据能量平衡理论建立了半解析数学模型。在任意射流冲击角度下,两侧切口轮廓的预测 R 方分别为 0.9455 和 0.9525,切削前阻力轮廓的预测 R 方为 0.9078。
Composites Part B: Engineering
Stability of crystallographic texture and mechanical anisotropy toward Al2O3/YAG eutectic ceramic composite using single crystalline seeds
Yuan Liu, Haijun Su, Xue Tan, Zhonglin Shen, Xiang Li, Hao Jiang, Di Zhao, Yinuo Guo, Zhuo Zhang, Min Guo
doi:10.1016/j.compositesb.2024.111263
使用单晶种子实现 Al2O3/YAG 共晶陶瓷复合材料结晶纹理和机械各向异性的稳定性
During the directional solidification of Al2O3-based eutectic ceramic composites, crystallographic orientation control is a promising method for tailoring the performances of composite parts. However, despite its importance in the fabrication of texture-controlled structural parts, the stable growth of the eutectic crystallographic texture for long distance (growth distance from 30 mm to 120 mm) in ceramic composite system is not widely understood. Herein, the competition and stability of crystallographic texture for Al2O3/YAG eutectic ceramic composite induced by different seeds using the Czochralski (CZ) technique were investigated. When the eutectic composites induced by different single crystalline Al2O3 seeds, coarse Al2O3 particles and uniform eutectic structure appeared alternately below the seeds. While the eutectic ceramic composite induced by YAG seed has a memory effect on the stability of its microstructure and morphology. We demonstrated that the eutectic ceramic composites induced by the〈112¯0〉Al2O3 and 101¯0〉Al2O3 seeds could stably inherit the seed orientation and grow as a single crystallographic texture with a low interfacial strain (<10 %). In particular, the stable evolution of crystallographic texture depended not only on the type of seeds but also on the mutual constraint of eutectic coupling growth. Furthermore, the nano-hardness, elastic modulus, and compressive strength (1600 °C) of the composites induced by different seeds have anisotropic characteristics. However, the bending strength was not sensitive to the change of crystallographic texture. It could maintain excellent high temperature stability, which was approximately 265∼316 MPa from room temperature to 1600 °C. These results promote the development of high-performance Al2O3-based eutectic ceramic composites with anisotropic design using seeding technique to tailor their crystallographic texture.
Structure-property relationship between lignin structures and properties of 3D-printed lignin composites
Shuyang Zhang, Anqi Ji, Xianzhi Meng, Samarthya Bhagia, Chang Geun Yoo, David P. Harper, Xianhui Zhao, Arthur J. Ragauskas
doi:10.1016/j.compscitech.2024.110487
木质素结构与三维打印木质素复合材料性能之间的结构-性能关系
Lignin is a low-cost and renewable bioresource with a huge annual production promising to prepare sustainable materials. However, the poor interfacial adhesion between many lignin-polymer pairs deteriorates the mechanical performance of the composites, which seriously limits the application of lignin in 3D printing via fused depositional modeling. This work examined lignin-polyamide 12 (PA 12) intermolecular interactions (e.g., hydrogen bonding) to address the interface challenge. To realize this goal, the phenolic hydroxyl content was increased on kraft softwood lignin by a LiBr/HBr demethylation procedure, increasing phenoxy content by 61.7%. Increased hydrogen bonding interactions between modified lignin (Pine-Lig-OH) and PA 12 demonstrated a significantly improved molten dynamic modulus by rheological analysis. Regarding mechanical properties, by adding 20 wt% of Pine-Lig-OH, the tensile strength and Young's modulus reached 46.6 MPa and 1.62 GPa, 30.2% and 33.9% higher than PA 12, respectively. Further morphological analysis proved the interfacial interactions are enhanced by showing the difference in the phase gaps. The dynamic mechanical analysis (DMA) supported the conclusion that Pine-Lig-OH could interact with polymer chains, alternating segmental movements due to the strong interaction. This study presents a method to enhance lignin composite properties by promoting interactions with the polymer matrix through modified functional groups, guiding future lignin composite research.