面向RC结构损伤演变的位移相关型阻尼模型及参数识别

DISPLACEMENT DEPENDENT DAMPING MODEL FOR RC STRUCTURE DAMAGE EVOLUTION AND PARAMETER IDENTIFICATION METHOD

针对目前阻尼模型不能充分反映钢筋混凝土结构阻尼与损伤之间关系的不足,提出位移相关型非线性阻尼模型,该模型既能反映结构振动过程中的粘滞阻尼耗能又能反映与结构损伤相关的内摩擦耗能。将内摩擦阻尼分解为残余应力效应和粘结滑移效应。基于能量守恒原理提出模型中阻尼参数的识别方法,并进行数值验证。对一钢筋混凝土简支梁进行损伤加载和动力测试,基于位移相关型非线性阻尼模型和相关动力学模型识别各损伤状态下的阻尼参数,分析其变化规律及非线性阻尼与损伤之间的内在联系。结果表明位移相关型阻尼模型不仅能反映阻尼比随位移峰值的增大而增大的现象,还能反映阻尼比随损伤程度的演变规律。

A displacement dependent nonlinear damping model was proposed to overcome the disadvantage associated with the current damping model, e.g. cannot represent the relationship between damping and the damage characteristics of reinforced concrete （RC） structure. The proposed damping model incorporated the viscous damping energy dissipation and the internal friction energy dissipation related to structural damage. The internal friction damping was decomposed into the residual stress effect and the bond slip effect. The identification method of damping parameters of the model was presented based on energy conservation principle, and the numerical simulation was carried out. Damage loading and dynamic test of a RC simply supported beam was carried out, and the damping parameters of each damage state were identified based on the proposed damping model and the corresponding dynamic model. The variation regularity and the intrinsic relationship between the nonlinear damping and the damage were analyzed. The results showed that the proposed damping model not only is able to characterize the fact that damping ratio increases with the increase of the displacement, but can represents the evolution behavior of damping ratio with damage degree.