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

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.