水分-载荷耦合作用下 2D 编织复合材料的 力学行为. (Chinese)

Mechanical behavior of 2D braided composites under the coupling effect of moisture and load. (English)

In order to study the moisture absorption behavior and performance degradation law of 2D braided composites under long-term moisture-load coupling, a moisture-load coupled aging device was designed. The moisture absorption test and tensile test after moisture absorption of carbon fiber reinforced epoxy resin (T300/H69) plain woven composite material under different stress levels were carried out. The results show that the moisture absorption of T300/H69 braided composites is positively correlated with the tensile prestress, and increases with the increase of tensile prestress. Compared with the effect of water alone, the elastic modulus and strength degradation of the material under moisture-load coupling are more obvious. After 432 h at 140%σs (σs is yield stress) prestress, the elastic modulus and failure strength of the braided composites decreased by 55.9% and 35.4%, respectively. In addition, the degradation mechanism of braided composites under long-term moisture-load coupling is further revealed by macro and micro section analysis. Based on Shiva's residual strength theory, the residual strength model of composites under moisture-load is improved, and the prediction results are good, which provides guidance for the durability design of composites in complex environment. [ABSTRACT FROM AUTHOR]

为了研究长期水分-载荷耦合作用下 2D 编织复合材料的吸湿行为及性能劣化规律, 设计了水分-载荷 耦合环境老化装置, 开展了不同应力水平下碳纤维增强环氧树脂 (T300/H69) 平纹编织复合材料的吸湿试验 及吸湿后的拉伸试验。结果表明: T300/H69 编织复合材料的吸湿量与拉伸预应力总体上呈现正相关, 随着 拉伸预应力的增大而增大；相对于水分单独作用, 水分-载荷耦合作用下材料的弹性模量和强度退化更明显, 在 140%σs (σs 为屈服强度) 预应力下作用 432 h 后, 编织复合材料的弹性模量及失效强度分别下降达 55.9% 和 35.4%。此外, 通过宏微观断面分析, 进一步揭示长期水分-载荷耦合作用下编织复合材料性能的退化机制, 并基于 Shiva 剩余强度理论, 改进了水分-载荷作用下复合材料的剩余强度模型, 预测结果良好, 为复杂环境 下复合材料耐久性设计提供指导。 [ABSTRACT FROM AUTHOR]

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