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为研究超高韧性水泥基复合材料(UHTCC)的疲劳特性,对其进行了弯曲疲劳试验;在UHTCC弯曲疲劳试验的基础上,从连续损伤力学出发,基于弹塑性各向同性损伤模型,研究了该材料在等幅重复荷载下的弯曲疲劳累积损伤性能,并建立了关于D-S的疲劳损伤模型。为准确描述该材料的损伤演变,模型中引用了起始损伤Ds的概念表示第Ⅰ变形阶段的损伤量;采用试件底面塑性应变εp作为变量计算损伤量D;根据试验曲线拟合得出损伤模型的各项参数。结果表明:UHTCC在不同应力水平S下的起始损伤量和累积损伤程度随应力水平的降低而变小,与实际情况相符;损伤模型的计算曲线与试验曲线吻合良好。
In order to study the fatigue properties of ultra-high toughness cementitious matrix composites (UHTCC), the flexural fatigue test was carried out. Based on the flexural fatigue test of UHTCC, based on the continuous damage mechanics, based on the elastic-plastic isotropic damage model, The cumulative fatigue damage of the material under bending load under constant amplitude and repeated load, and established a fatigue damage model for DS. In order to accurately describe the damage evolution of the material, the concept of initial damage Ds is used in the model to represent the damage amount in the first deformation stage. The plastic strain εp at the bottom of the specimen is used as a variable to calculate the damage amount D, and the damage is obtained through fitting the test curve The parameters of the model. The results show that the initial damage and the cumulative damage of UHTCC at different stress levels S decrease with the decrease of stress level, which agrees with the actual situation. The calculated curve of the damage model is in good agreement with the experimental curve.