混凝土疲劳变形曲线三阶段的比例关系与应变速率

Proportion relation and strain rate of three-stage concrete’s fatigue deformation curve

为更加准确地描述混凝土疲劳变形曲线的演变规律,对变形曲线三阶段的比例关系及其应变速率的变化规律进行了研究。定性分析了疲劳应变速率的变化趋势和特征,提出了基于疲劳应变速率划分疲劳变形曲线三阶段的方法,在此基础上,采用回归分析的方法分析了三阶段的比例、应变速率与应力水平和疲劳寿命之间的关系,建立了基于三阶段比例关系和应变速率的疲劳变形曲线演化方程。结果表明,基于应变速率划分疲劳变形曲线的三个阶段比目测法具有更高的精度,基于三阶段比例关系和应变速率的疲劳变形曲线演化方程能更充分地描述疲劳变形曲线的细部特征。

To describe the evolution law of concrete’s fatigue deformation curves more exactly,the proportion relations of its three stages and the change rules of strain rates are studied.The latter and its features are qualitatively analyzed.The method that can be used to divide these three stages is proposed according to the fatigue strain rate.A regression analysis method is adopted to study the ratios among these three stages and the relations of strain rate,stress level and fatigue life.Fatigue deformation evolution formulas are established based on the proportion relations of these three stages and strain rate.The results show:the proposed method to divide three stages can improve the precision compared with the visual method;the newly established formulas can describe more detailed information of fatigue deformation curves.