预应力活性粉末混凝土道面板的疲劳损伤试验研究及有限元分析

Fatigue damage test and finite element analysis of prestressed reactive powder concrete pavement

为了研究疲劳荷载对预应力活性粉末混凝土道面板损伤性能的影响,设计4块尺寸为5 m×2.5 m×0.12 m的试件进行试验。试验采用的应力比为0.3,试件经200万次加载后未疲劳破坏。并利用有限元软件Ansys Workbench与疲劳分析软件Ncode Designlife对试件进行了仿真模拟,研究应力水平与损伤之间的关系。结果表明:RPC道面板的损伤主要集中于前20万次的加载过程,且受拉区的损伤要大于受压区,受拉区的跨中位置为疲劳破坏的薄弱位置;预应力对于试件损伤的减少,主要是减少了20万次后加载过程产生的损伤,使得相同等级的RPC平均疲劳寿命提高1.3~1.8倍,破坏时的损伤值减少25%~40%;取0.5作为作为变形模量的极限值,经回归分析提出变形模量的计算表达式;应力水平0.7可作为损伤的拐点,小于0.7时损伤值增长缓慢,疲劳寿命超过200万次,0.7及以上时损伤值成数十倍甚至上百倍增长,疲劳寿命显著下降。

In order to study influence of fatigue load on the damage performance of prestressed reactive powder concrete pavement,four specimens with the size of 5 m×2.5 m×0.12 m were designed for test.The stress ratio used in the test is 0.3,and the specimen has not been fatigue damaged after 2 million times of loading.The strain of concrete and the deflection of specimen are measured during the loading process.In addition,the finite element software ANSYS Workbench and fatigue analysis software ncode Designlife are used to simulate the specien,and relationship between stress level and damage is studied.The results show that:the concrete strain rate,stiffness degradation degree and deformation modulus reflect the change of specimen damage;the damage of RPC pavement is mainly concentrated in the first 200000 loading processes,and the damage in the tensile zone is greater than that in the compression zone,and the mid span position of the tension zone of the pavement caused by fatigue loading is called the weak position of fatigue failure;the prestressed reduces the damage of specimen,mainly reduces the damage in the loading process after 200000 times,so that the RPC of the same grade is average The fatigue life is increased by 1.3~1.8 times,and the damage value is reduced by 25%~40%;0.5 is taken as the limit value of deformation modulus,and the calculation expression of RPC deformation modulus is put forward through regression analysis;the stress level 0.7 can be used as the inflection point of damage,when it is less than 0.7,damage value increases slowly,fatigue life is more than 2 million times,damage value is tens of times or even hundreds of times when it is 0.7 or above,and fatigue life is more than 2 million times,life span decreased significantly.