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为了解碳纤维束的疲劳特性及疲劳加载后剩余强度的变化,为建立碳纤维复合材料疲劳性能的细观力学分析模型提供必要的基础数据,研究设计了碳纤维束静载力学性能及疲劳特性试验方案,并进行了试验。采用最小二乘法拟合得到了单束碳纤维的应力-寿命(S-N)曲线。对经过预疲劳的碳纤维束试验件进行了剩余强度试验,采用最小二乘法拟合得到了碳纤维束疲劳加载剩余强度模型。试验结果表明:试验所用碳纤维束的条件疲劳极限为静拉伸强度的80.47%;碳纤维束经历一定循环次数的拉-拉疲劳可以提高其强度,其剩余强度随着疲劳加载循环次数的增加先增加后减小。
In order to understand the fatigue characteristics of carbon fiber bundles and the residual strength changes after fatigue loading, to provide the necessary basic data for the establishment of the meso-mechanics analysis model of the fatigue properties of carbon fiber composites, the test scheme of the static mechanical properties and fatigue properties of carbon fiber bundles was studied, And conducted a test. The stress-life (S-N) curves of single-bundle carbon fibers were obtained by least squares fitting. The residual strength of pre-fatigue carbon fiber bundles was tested, and the residual strength model of the carbon fiber bundles under fatigue loading was obtained by least square fitting. The experimental results show that the fatigue limit of the carbon fiber bundles used in the experiment is 80.47% of the static tensile strength. The tensile strength of the carbon fiber bundles after a certain number of cycles can be increased, and the residual strength first increases with the increase of the fatigue loading cycles After the decrease.