Wang Xin, Li Hanhua, Zhang Yuxuan, Guan Yue, Yan Shi, Zhai Junjun
Department of Engineering Mechanics, Harbin University of Science and Technology, Harbin 150080, China.
Department of Engineering Mechanics, Beijing Institute of Astronautical Systems Engineering, Beijing 100076, China.
Materials (Basel). 2024 Aug 2;17(15):3821. doi: 10.3390/ma17153821.
The low delamination tendency and high damage tolerance of three-dimensional (3D) braided composites highlight their significant potential in handling defects. To enhance the engineering potential of three-dimensional four-directional (3D4d) braided composites and assess the failure mode of hole defects, this study introduces a series of 3D4d braided composites with prefabricated holes, studying their compressive properties and failure mechanisms through experimental and finite element methods. Digital image correlation (DIC) was used to monitor the compressive strain on the surface of materials. Scanning acoustic microscope (SAM) and scanning electron microscopy (SEM) were used to characterize the longitudinal compression failure mode inside the material. A macroscopic model is established, and the porous materials are predicted by using the general braided composite material prediction theory. While reducing the forecast cost, the error is also controlled within 21%. The analysis of failure mechanisms elucidates the damage extension mode, and the porous damage tolerance ability aligns closely with the bearing mode of braided material structure. Different braiding angles will lead to different bearing modes of materials. Under longitudinal compression, the average strength loss of 15° specimens is 38.21%, and that of 30° specimens is 8.1%. The larger the braided angle, the stronger the porous damage tolerance. Different types of prefabricated holes will also affect their mechanical properties and damage tolerance.
三维（3D）编织复合材料的低分层倾向和高损伤容限突出了它们在处理缺陷方面的巨大潜力。为了提高三维四向（3D4d）编织复合材料的工程潜力并评估孔洞缺陷的失效模式，本研究引入了一系列带有预制孔的3D4d编织复合材料，通过实验和有限元方法研究它们的压缩性能和失效机制。使用数字图像相关（DIC）技术监测材料表面的压缩应变。利用扫描声学显微镜（SAM）和扫描电子显微镜（SEM）对材料内部的纵向压缩失效模式进行表征。建立了宏观模型，并采用通用编织复合材料预测理论对多孔材料进行预测。在降低预测成本的同时，误差也控制在21%以内。对失效机制的分析阐明了损伤扩展模式，多孔损伤容限能力与编织材料结构的承载模式密切相关。不同的编织角度会导致材料不同的承载模式。在纵向压缩下，15°试样的平均强度损失为38.21%，30°试样的平均强度损失为8.1%。编织角度越大，多孔损伤容限越强。不同类型的预制孔也会影响它们的力学性能和损伤容限。
