混凝土抗压疲劳剩余强度损伤模型

目的建立混凝土抗压疲劳剩余强度随疲劳次数衰减的模型，揭示混凝土疲劳剩余强度衰减规律．方法基于连续体损伤力学理论，采用应变能量释放率空间的边界面模型，通过极限断裂面的不断移动来模拟疲劳过程中损伤阂值的变化情况．结果建立了累积损伤与相应循环损伤能量释放率之间的函数关系，确定了疲劳加载中极限断裂面尺寸的变化规律，在高周疲劳过程里损伤模量表达式中D是变量，且与剩余强度有关．利用模型编制计算机程序，绘出了不同最大应力水平下混凝土疲劳剩余抗压强度的衰减曲线．结论变量D反映出混凝土疲劳剩余衰减的特性，模型的计算结果能较好反映试验结果的变化规律．

Damage Model for the Residua Strength of Concrete under Compression Fatigue Loading

Based on the continuum damage mechanics, an anisotropic elasto-damage model for predicting the residual strength of concrete under compression fatigue loading is presented in this study. The model utilizes the concept of multiple bounding surfaces, With a varying size limit fracture surface defining fatigue loading. D variable in the damage modulus expression is not constant under high cycles. It is a variable depending on the residual strength. The calculation parameters of the model are given according to the fatigue test results acquired by the authors. Comparison of the residual strength results indicates good agreement between the theoretical model and the experimental data.