碳纤维束疲劳损伤失效试验

Experiments on fatigue damage failure test of carbon fiber yarn

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 the carbon fiber yarn and the residual strength of the carbon fiber yarn after fatigue loading, an experiment program was designed and conducted under the static and fatigue loading conditions. The test data was used to establish a micromechanics analysis model for analyzing the fatigue characteristics of carbon fiber composite materials. The stress-life （S-N） curve of the carbon fiber yarn was fitted by the least squares method. A static tension experiment was conducted using carbon fiber yarn after fatigue loading to set up the expression of the residual strength model. The experimental results show that the conditional fatigue limit of the carbon fiber yarn is 80.47% of the static tension strength. Carbon fiber yarn going through a certain number of tension-tension fatigue loading cycles can increase its strength. The residual strength of the carbon fiber yarn increases firstly and then decreases with the increasing of fatigue loading cycles.