今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 2 篇
Modeling via peridynamics for crack propagation in laminated glass under fire
W.K. Sun, B.B. Yin, Jinhua Sun, V.K.R. Kodur, K.M. Liew
doi:10.1016/j.compstruct.2024.118112
火灾作用下夹层玻璃裂纹扩展的周动力学模拟
Despite laminated glass is widely used in building construction, its susceptibility to cracking and collapsing during an accidental fire can intensify fire propagation, leading to substantial casualties and economic losses. In this work, we developed a meshfree framework for modeling thermomechanical cracking of laminated glass via peridynamic (PD) theory. First, to overcome the incomplete input experimental data for implementing thermal boundary conditions, we proposed both the uniform and non-uniform temperature field strategies. Second, PD interface model and the stochastic distribution of defects were implemented within this framework. Third, the challenging problem of crack path selection in thermally loaded borosilicate/steel bi-material beams was studied to validate the feasibility of the proposed model. It is demonstrated that the proposed framework can capture the temperature history and crack features of laminated glass under fire, showing great consistency with experimental results. Our findings show that with the decrease of the glass strength or the increase of the defect content, more islands form in the central region of the glazing, implying higher risks of glass fall-out in fire conditions. This model constitutes a promising tool for predicting the fire performance of laminated glass and contributes to designing safer engineering structures.
尽管夹层玻璃在建筑施工中应用广泛,但其在意外火灾中容易开裂和倒塌,从而加剧了火灾的蔓延,导致大量人员伤亡和经济损失。在这项工作中,我们开发了一个无网格框架,通过动力学(PD)理论来模拟夹层玻璃的热机械开裂。首先,为了克服实现热边界条件输入实验数据不完整的问题,我们提出了均匀和非均匀温度场策略。其次,在此框架下实现了PD界面模型和缺陷的随机分布;第三,研究了热加载硼硅/钢双材料梁的裂纹路径选择问题,验证了所提模型的可行性。实验结果表明,所提出的框架能较好地捕捉夹层玻璃在火灾下的温度历史和裂纹特征,与实验结果有较好的一致性。我们的研究结果表明,随着玻璃强度的降低或缺陷含量的增加,在玻璃的中心区域形成更多的岛屿,这意味着在火灾条件下玻璃脱落的风险更高。该模型是预测夹层玻璃防火性能的有效工具,有助于设计更安全的工程结构。
High-performance C/C composites derived from phthalonitrile matrix CFRP via a few cycles of vacuum-assisted impregnation-carbonization
V. Aleshkevich Vladislav, S. Morozov Oleg, V. Babkin Alexander, V. Kepman Alexey, A. Bulgakov Boris
doi:10.1016/j.compositesa.2024.108201
以邻苯二腈基CFRP为原料,通过真空辅助浸渍-碳化制备高性能C/C复合材料
Novel approach of fabrication of carbon–carbon composites from carbon fiber reinforced plastics with phthalonitrile matrices was presented. Polymer composites were obtained by vacuum infusion, carbonized, and reimpregnated with following carbonization to reduce porosity of the resulting materials. The highest mechanical properties and lowest porosity were obtained when CFRP post-cured at 375 °C was taken initially. 4 cycles of impregnation-carbonization are sufficient to fabricate materials with the highest properties. Phthalonitrile resin transformations through curing, carbonization and graphitization using XRD, Raman spectroscopy, elemental analysis, FTIR and solid-state NMR were researched. TGA-MS revealed exposure of CH4, NH3, H2O, HCN, benzene and phenol gases during carbonization. Amorphous carbon materials were obtained after carbonization at 1000 °C with ID/IG = 2.38 and graphitization at 2200 °C resulted in formation of more structured carbon material with ID/IG = 0.63. Mechanical and thermal properties of the composites were determined at every step of the process.
提出了以邻苯二腈为基体的碳纤维增强塑料为原料制备碳-碳复合材料的新方法。聚合物复合材料通过真空灌注、碳化、再浸渍和后续碳化来减少材料的孔隙率。在375 °C初始固化时,CFRP获得了最高的力学性能和最低的孔隙率。浸渍-碳化4次循环就足以制备出性能最高的材料。采用XRD、拉曼光谱、元素分析、FTIR和固态核磁共振等方法研究了邻苯二腈树脂经固化、碳化和石墨化后的转化。TGA-MS分析了碳化过程中CH4、NH3、H2O、HCN、苯和酚等气体的暴露。在1000 °C下碳化得到非晶碳材料,ID/IG = 2.38;在2200 °C下石墨化得到结构更完善的碳材料,ID/IG = 0.63。在工艺的每一步都测定了复合材料的力学和热性能。
Predictive modeling of 3D textile composites using realistic micromechanical representations
Agniprobho Mazumder, Li Zheng, Yang Jiao, Todd Bullions, Yong Yu, Youqi Wang
doi:10.1016/j.compositesb.2024.111441
三维纺织复合材料的预测建模使用现实的微机械表示
An innovative and efficient progressive damage model, informed by coupon tests, and using minimal, readily available material parameters, is proposed in this paper to comprehensively predict the tensile, compressive and shear stress–strain response and strengths of a 3D woven angle interlock composite within 5% of test data. Realistic, high-fidelity microgeometries, with process-induced defects, and devoid of geometric assumptions, are constructed using the digital element approach. Excellent correlations with test micrographs are observed for yarn cross-section areas, aspect ratios and crimp ratios, that are on average within 5.5%, 1.9% and 1% of the micrograph measurements respectively. The mesoscale predictions capture the detailed failure mechanisms under each loading condition. Analytical stiffness expressions are derived in terms of the constituent material elastic properties and architecture geometry, which also predict the stiffnesses within 10% error margin. A robust workflow is established that combines the high-fidelity microgeometry generation, automated conformal finite element model creation and comprehensive property prediction capabilities to provide a holistic solution.
本文提出了一种创新的、高效的渐进损伤模型,该模型以粘片试验为依据,使用最小的、可获得的材料参数,在5%的试验数据范围内综合预测三维编织角互锁复合材料的拉伸、压缩和剪切应力应变响应和强度。现实的,高保真的微几何,与过程引起的缺陷,和缺乏几何假设,使用数字元素方法构建。观察到纱线的横截面面积、纵横比和卷曲比与测试显微照片的良好相关性,其平均值分别在显微照片测量值的5.5%、1.9%和1%之内。中尺度预测捕获了每种加载条件下的详细破坏机制。推导了基于构件材料弹性性能和结构几何的刚度解析表达式,预测刚度误差在10%以内。建立了一个强大的工作流程,结合了高保真的微几何生成、自动保形有限元模型创建和全面的性能预测能力,提供了一个整体的解决方案。
Thermoplastic and Thermoset Polymer Matrix Composites Reinforced with Bismuth Oxide as Radiation Shielding Materials
S. Bagheri, H. Khalafi, M.R. Tohidifar, Sa. Bagheri
doi:10.1016/j.compositesb.2024.111443
氧化铋增强热塑性和热固性聚合物基复合材料作为辐射屏蔽材料
Polymer composites reinforced with heavy metals have wide applications in the nuclear industry as radiation shielding materials against emitted radiation from nuclear equipment. In this study, considering bismuth oxide as reinforcement, various polymers including thermoplastic polymers, such as high-density polyethylene, low-density polyethylene, polypropylene, polyvinyl acetate, polymethyl methacrylate, and thermosetting epoxy resin have been considered as matrices. After preparing various samples of polymer composites loaded with 60% by weight of bismuth oxide, some physical, mechanical, and radiation shielding properties (neutron and gamma attenuation coefficients) of these polymer composites have been measured and compared with each other. First, the density of the samples was measured, and the response of these samples to varying compressive force was investigated. The stress-strain diagrams of composites with different matrices were compared. Subsequently, the linear and mass attenuation coefficients of the composites were measured over a wide range of energies (32-1480 keV) against direct and collimated beams from various standard gamma-ray sources (134Cs, 60Co, 154Eu, 133Ba, and 22Na) using an HPGe detector. A collimated beam from an Am-Be source was utilized to measure and compare the attenuation properties of the composite samples against neutron flux. Furthermore, the properties of the composites against neutron and gamma radiation were calculated using the MCNP Monte Carlo code over a broad energy range, and the results were compared and validated with the experimental data. The comparison of the calculated and measured results shows reasonable agreement. The results indicate that in situations where high attenuation properties coupled with high strength are desired, polymeric composites with an epoxy matrix can be considered as radiation shielding materials. If the use of flexible and malleable material is required, such as for reactor piping shielding or the fabrication of protective gloves and clothing in a radiation environment, among the polymers studied, polyvinyl acetate is a more suitable matrix.
重金属增强聚合物复合材料作为屏蔽核设备辐射的材料,在核工业中有着广泛的应用。本研究以氧化铋为增强剂,以各种聚合物为基体,包括高密度聚乙烯、低密度聚乙烯、聚丙烯、聚醋酸乙烯、聚甲基丙烯酸甲酯、热固性环氧树脂等热塑性聚合物。在制备了负载重量为60%的氧化铋的各种聚合物复合材料样品后,测量了这些聚合物复合材料的一些物理、机械和辐射屏蔽性能(中子和γ衰减系数)并相互比较。首先,测量了试样的密度,研究了试样对不同压缩力的响应。比较了不同基体复合材料的应力-应变图。随后,使用HPGe探测器测量了复合材料的线性衰减系数和质量衰减系数,测量了不同标准伽玛射线源(134Cs, 60Co, 154Eu, 133Ba和22Na)的直接和准直光束在较宽能量范围内(32- 1480kev)的衰减系数。利用Am-Be源的准直光束测量和比较了复合材料样品对中子通量的衰减特性。利用MCNP蒙特卡罗程序计算了复合材料在较宽能量范围内的抗中子和γ辐射性能,并与实验数据进行了比较和验证。计算结果与实测结果比较,结果吻合较好。结果表明,在需要高衰减性能和高强度的情况下,环氧基聚合物复合材料可以作为辐射屏蔽材料。如果需要使用柔性和延展性材料,例如用于反应堆管道屏蔽或在辐射环境中制造防护手套和衣服,那么在所研究的聚合物中,聚醋酸乙烯酯是更合适的基质。
Theoretical prediction and validation of mechanical properties and damage of 3D orthogonal woven composites with different parameters
Xue Yang, Tian-lei Yao, Dian-sen Li, Lei Jiang
doi:10.1016/j.compscitech.2024.110591
不同参数下三维正交编织复合材料力学性能及损伤的理论预测与验证
In this work, microscopic models of three-dimensional orthogonal woven composites (3DOWCs) were developed according to the actual structural relationships of yarns. By introducing a bridging model for 3DOWCs, elastic constants, tensile, compression, and shear strength of 3DOWCs with varying yarn densities were predicted and discussed by means of the established stress-strain relationships. Meanwhile, the flexural properties were also examined employing finite element models derived from the results of the bridging model predictions. The anticipated results exhibited excellent agreement with the reported experimental data. The results demonstrated that the elastic modulus (E), tensile, and compression strength, and the shear strength in the XY- and XZ-directions increased with yarn densities, while the shear modulus (G) and YZ-direction shear strength decreased. In comparison to 3DOWCs with DT/DZ=2 yarn/cm and DW=1.5 yarn/cm (small densities), the Ez, Ex, and Ey of 3DOWCs with DT/DZ=4 yarn/cm and DW=3 yarn/cm (large densities) were enhanced by 42.3%, 193.2%, and 174.1%, respectively. Meanwhile, the tensile and compression strength of 3DOWCs with large densities were also higher than those of 3DOWCs with small densities. Additionally, the variation in flexural strength was similar to that of tensile and compression strength, which increased by 41.1%. Large densities 3DOWCs with higher fiber contents experienced minor cracking during flexural loading because of their ability to maintain structural integrity, whereas stress concentration in the contact region with the indenter was the primary damage to small densities 3DOWCs.
本研究根据纱线的实际结构关系建立了三维正交编织复合材料(3DOWC)的微观模型。通过引入三维正交编织复合材料的桥接模型,利用已建立的应力应变关系预测并讨论了不同纱线密度的三维正交编织复合材料的弹性常数、拉伸强度、压缩强度和剪切强度。同时,根据桥接模型的预测结果推导出的有限元模型也对弯曲性能进行了检验。预期结果与实验数据非常吻合。结果表明,弹性模量 (E)、拉伸和压缩强度以及 XY 和 XZ 方向的剪切强度随纱线密度的增加而增加,而剪切模量 (G) 和 YZ 方向的剪切强度则有所下降。与 DT/DZ=2 纱/厘米和 DW=1.5 纱/厘米(小密度)的 3DOWC 相比,DT/DZ=4 纱/厘米和 DW=3 纱/厘米(大密度)的 3DOWC 的 Ez、Ex 和 Ey 分别提高了 42.3%、193.2% 和 174.1%。同时,大密度 3DOWC 的拉伸强度和压缩强度也高于小密度 3DOWC。此外,抗弯强度的变化与抗拉强度和抗压强度的变化相似,都增加了 41.1%。由于纤维含量较高的大密度 3DOWC 能够保持结构的完整性,因此在挠曲加载过程中会出现轻微开裂,而与压头接触区域的应力集中则是小密度 3DOWC 的主要损坏部位。
Modelling Effective Thermal Conductivity in Polymer Composites: A Simple Cubic Structure Approach
Lu He, Zhengli Dou, Yongzheng Zhang, Qiang Fu, Kai Wu
doi:10.1016/j.compscitech.2024.110592
聚合物复合材料的有效导热建模:一种简单的立方结构方法
In this study, we propose the simple cubic model, a distinctive thermal-conductive mathematics for modelling the effective thermal conductivity in polymer composites, taking both filler size and interface thermal resistance into account. This model is constructed by delineating heat transport paths within simple cubic structural units, leveraging principles involving Fourier's law, minimum thermal resistance, specific equivalent thermal conductivity, and thermal resistance network. Demonstrating broad applicability, the simple cubic model accurately predicts effective thermal conductivity within a 0-40% volume fraction range of filler in polymer composites, maintaining less than 15% error. Its robustness is validated across over 100 experimental datasets, encompassing various polymer matrices and granular filler types. This extensive validation underscores the model's efficacy, both with our experimental data and existing literature. The simple cubic model's insightful predictions make it valuable in designing and preparing thermally conductive polymer composites.
在这项研究中,我们提出了简单的立方模型,这是一种独特的导热数学,用于模拟聚合物复合材料的有效导热性,同时考虑了填料尺寸和界面热阻。该模型是通过描述简单立方结构单元内的热传递路径,利用涉及傅立叶定律、最小热阻、比等效导热系数和热阻网络的原理构建的。简单的立方模型具有广泛的适用性,可以准确预测聚合物复合材料中填料体积分数在0-40%范围内的有效导热系数,误差小于15%。其稳健性在100多个实验数据集中得到验证,包括各种聚合物基质和颗粒填料类型。通过我们的实验数据和现有文献,这种广泛的验证强调了模型的有效性。简单的立方模型的深刻预测使其在设计和制备导热聚合物复合材料方面具有重要的价值。