BFRP筋温度损伤后的疲劳性能研究

开展温度损伤后的玄武岩纤维增强复合材料(BFRP)疲劳性能研究,对其在高温环境中的合理使用具有重要意义。提出改进单点-成组法,借助灰色理论GM(1,1)模型结合极值原理对疲劳S-N曲线三参数表达式进行回归分析,推导随应力水平变化的三参数Weibull概率密度函数,根据极大似然估计原理确定分布参数。通过非线性拟合方法建立综合考虑温度和可靠度影响的Weibull概率疲劳T-P-S-N模型。通过温度损伤后的BFRP筋疲劳性能试验研究温度损伤对其疲劳性能的影响,并验证理论模型。结果表明:BFRP筋疲劳寿命随温度和可靠度的升高疲劳寿命呈下降趋势,与实际相符;建议模型能较好描述BFRP筋疲劳性能随温度和可靠度的变化趋势。

Fatigue properties of BFRP bars after temperature damage

The fatigue property of basalt fiber reinforced composites (BFRP) with cumulative thermal damage was studied, which is of great significance for its proper use under high temperature condition.An improved Single Point Group method was proposed to do a regressive analysis on a three-parameter expression of the fatigue S-N curve.The gray theory GM (1,1) model and the extreme value principle were introduced to derive a three-parameter Weibull probability density function varying with corresponding stress level, and the distribution parameters were determined by the maximum likelihood estimation method.A Weibull probabilistic fatigue T-P-S-N model was established through the nonliear fitting, considering the comprehensive effect of temperature and reliability, which was then validated by using the fatigue test of a high temperature affected BFRP bar.The results demonstrate that the downtrend of fatigue life of BFRP bar can be apparently observed when the external temperature and reliability ascend, which corresponds well to the practical situation.The proposed model is able to properly describe the trend of fatigue behavior of BFRP with varied temperature and reliability.