等幅疲劳荷载作用下超高韧性水泥基复合材料弯曲疲劳寿命试验研究  

Study on flexural fatigue life of ultra-high toughness cementitious composites under constant amplitude cyclic loading

作　　者：刘问[1] 徐世烺[1,2] 李庆华[2] 

机构地区：[1]大连理工大学结构工程研究所,辽宁大连116024 [2]浙江大学高性能建筑结构与材料研究所,浙江杭州310058

出　　处：《建筑结构学报》2012年第1期119-127,共9页Journal of Building Structures

基　　金：国家自然科学基金重点项目(51008270)

摘　　要：通过弯曲疲劳试验研究了超高韧性水泥基复合材料(UHTCC)的弯曲疲劳寿命、疲劳变形以及破坏特征等。试验结果表明:疲劳荷载作用下,UHTCC也会产生多条裂缝,随应力水平降低,裂缝数目减少,使得其变形能力减弱;疲劳破坏后,试件断面可分为3个不同区域,且不同应力水平下,纤维的拔出破坏和拉断破坏比例不同。UHTCC疲劳寿命服从双参数的威布尔分布,根据威布尔参数拟合的S-N双对数方程呈明显的双线性特征,原因是在低周与高周疲劳荷载循环作用下UHTCC中PVA纤维发挥作用的程度有所不同。This paper presented an experimental study on the flexural fatigue properties of Ultra-High Toughness Cementitious Composites （UHTCC）. The deflection ability, failure characteristics and fatigue life were investigated. It is observed that, similar to the static specimen, multiple cracks are formed in fatigue specimens, while the number of cracks decreases with the degradation of stress levels. For this reason, the deformability is much weaker at lower fatigue stress levels than that at higher stress levels. Moreover, the failure plane can be divided into three different regions, and the proportions of fiber rupture to fiber pullout are different under different stress levels. The fatigue life of UHTCC flexural specimens obeys two-parameter weilbell distribution. Based on the weilbull parameters, the S-N relation of UHTCC is fitted on a bi-logarithmic scale, which exhibits a bilinear feature due to the different effect level of PVA fiber under low-cycle loading and high-cycle loading.

关 键 词：超高韧性水泥基复合材料 弯曲疲劳试验 变形特征 破坏形式 疲劳寿命方程 

分 类 号：TU375.1[建筑科学—结构工程] TU317.1