中文摘要：

为了评估钢筋混凝土（RC）构件的损伤状态，在Maltab中建立了基于刚度退化和纤维梁柱单元的损伤模型．首先在OpenSees中建立基于纤维梁柱单元的构件、结构数值分析模型，将分析模型所得到的纤维应力、应变值导入在Matlab中所建立的损伤模型，并计算纤维、截面、构件的损伤值．所建立的损伤模型使用再加载刚度退化定义混凝土纤维的损伤，使用低周疲劳准则定义钢筋纤维的损伤，使用塑性应变定义预应力筋的损伤，并分别使用截面抗弯刚度退化、杆端抗弯刚度退化评估截面、构件的损伤．最后，选取循环荷载作用下的一榀预应力混凝土框架结构试验，对所建立损伤模型的适用性进行验证．结果表明：该损伤模型不仅可以准确地预测构件的损伤状态，而且可通过刚度组装和静力凝聚方法在各层次损伤指数间建立紧密的联系．此外，所建立的损伤模型将来可被嵌入OpenSees，直接实现针对混凝土构件和结构的损伤评估．

英文摘要：

To estimate the damage state of reinforced concrete （RC） members, a damage model was established based on stiffness degradation and fiber beam-column elements in Matlab. Firstly, the numerical analysis model of a member or a structure based on fiber beam-column elements was established in OpenSees, and the strains and stresses of fibers outputted by OpenSees were then read into the damage model established by Matlab, which estimated the damage values at fiber, section, and member levels. In the es tablished model, fiber damages of concrete, reinforcing steel, and prestressing tendon were defined by the initial reloading modulus degradation, low-cycle fatigue law, and plastic strain, respectively. The section and member damage states were then evaluated by the degradation of the sectional bending stiffness and rod-end bending stiffness, respectively. The established al test results of prestressed concrete frame subjected to model was verified by comparison with a structurcyclic loads. The results indicate that the damage model can determine its damage states accurately, and a close relationship between damage indices at various levels by using the direct stiffness method and static condensation method. Furthermore, the estab- lished damage model can be embedded in OpenSees to determine the damage states of RC members and structures directly in the future.