Zhang Xiaowen, Zhu Haiyang, Lv Zhixing, Zhao Xiangrun, Wang Junwei, Wang Qi
School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China.
National Key Laboratory of Combustion, Thermo-Structure and Flow, The 41st Institute of the Fourth Academy of CASC, Xi'an 710025, China.
Materials (Basel). 2022 Oct 10;15(19):7034. doi: 10.3390/ma15197034.
The biaxial loading properties of carbon-fiber-reinforced polymer (CFRP) are critical for evaluating the performance of composite structures under the complex stress state. There are currently no standardized specimens for the CFRP biaxial experiments. This work developed a new design criterion for the cruciform specimen coupled with the Hashin criterion. The finite element analysis was conducted to investigate the effect of geometric parameters on the stress distribution in the test area. The embedded continuous laying method (ECLM) was proposed to achieve the thinning of the center of the test region without introducing defects. The manufacturing quality of the cruciform specimens was verified by the ultrasonic C-scanning test. The biaxial test platform consisting of the biaxial loading system, digital image correlation (DIC) system, strain electrical measurement system, and acoustic emission detection system was constructed. The biaxial tensile tests under different biaxial loading ratios were conducted. The results showed that the biaxial failure efficiently occurred in the test area of the cruciform specimens designed and manufactured in this paper. The failure modes and morphology were characterized using macro/microscopic experimental techniques. The biaxial failure envelope was obtained. The results can be used to guide the design of composite structures under biaxial stress.
碳纤维增强聚合物（CFRP）的双轴加载特性对于评估复合结构在复杂应力状态下的性能至关重要。目前尚无用于CFRP双轴试验的标准试样。本文提出了一种结合Hashin准则的十字形试样新设计准则。通过有限元分析研究了几何参数对试验区域应力分布的影响。提出了嵌入式连续铺设方法（ECLM），以在不引入缺陷的情况下实现试验区域中心的减薄。通过超声C扫描试验验证了十字形试样的制造质量。构建了由双轴加载系统、数字图像相关（DIC）系统、应变电测量系统和声发射检测系统组成的双轴试验平台。进行了不同双轴加载比下的双轴拉伸试验。结果表明，本文设计制造的十字形试样试验区域有效地发生了双轴破坏。采用宏观/微观试验技术对破坏模式和形态进行了表征。得到了双轴破坏包络线。研究结果可用于指导双轴应力作用下复合结构的设计。
