The traditional damping models generally include such models as the viscous damping,the coulomb damping,the complex damping and the stress damping.These models cannot sufficiently reveal the rule and phenomenon how the damp varies with the damage evolution.It is assumed that the damping energy dissipation of the reinforced concrete structures mainly consists of the viscous damping and the residual stress damping,and the residual stress damping includes the bond stress between the reinforcement and the concrete and the friction stress of the concrete cracks.On the basis of this assumption,a combined damping model based on the residual stress is proposed.The dynamic equation of the structure containing viscous and coulomb damping is established,and the formula of the damping ratio with the development of damage is derived.The damping change regulation of the reinforced concrete structures under different damage states is analyzed.It is found that the damping ratio of different damage degree is remarkably affected by the ratio of the residual stress and the stiffness,and diverseparameters of the combined damping model are available and has better adaptability.Finally,the change of damping with the damage of reinforced concrete simply-supported beam is tested by the static damage experiment,and the mechanism of the change of the damping ratio with different damage is analyzed combined with numerical simulation.The results show that the combined damping model has a definite mechanical mechanism,and the phenomenon that the damping ratio of the reinforced concrete beam originally increases and subsequently decreases with the damage degree is accurately revealed.%传统阻尼模型包括黏滞型、库仑型、复阻尼型及应力型等,以上模型在表征阻尼随结构损伤演变的变化规律方面存在不足.认为钢筋混凝土结构的阻尼耗能主要包括黏滞阻尼耗能和残余应力阻尼耗能,且残余应力包括钢筋和混凝土之间的黏结应力以及混凝土裂缝间的摩擦应力.在此基础上提出基于残余应力的复合阻尼模型,并建立包含黏滞和库仑阻尼的结构动力方程,推导阻尼比随损伤变化公式.分析不同损伤程度下钢筋混凝土结构的阻尼比变化规律,发现残余应力与刚度的比值明显影响损伤过程中阻尼的变化趋势,且复合阻尼模型的参数丰富,适应性强.最后,通过钢筋混凝土简支梁静力损伤试验测试阻尼随损伤程度的变化,结合数值模拟研究阻尼比随损伤程度变化的机理.结果表明:提出的阻尼模型具有明确的力学机理,能够准确地反映钢筋混凝土梁式结构阻尼比随损伤先增大后减小的规律.
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