非线性阻尼模型对重力坝地震响应的影响

阻尼对结构的振动反应有重要影响,目前重力坝设计阶段通常取阻尼比为常数,但不能真实反映结构的阻尼机理。为此,基于大型通用有限元软件ABAQUS,利用混凝土损伤塑性模型分析了重力坝在地震荷载作用下的损伤发展和能量耗散,提出了重力坝结构非线性阻尼模型的表达式,分别采用非线性阻尼模型和常阻尼模型计算了重力坝在三向地震波作用下的响应,并对结果进行了对比。结果表明,采用非线性阻尼模型计算的结构响应较大,因此采用常阻尼比模型进行结构地震响应分析可能产生不安全的结果。

Influence of Non-linear Damping on Seismic Response of Gravity Dam

Damping as a material property has significant influence on the dynamic responses of structures. Damping ratio is usually regarded as a constant when designing the gravity dam at present, and it is not consistent with the damping mechanism. In this paper, through analyzing the damage development and energy dissipation of a gravity dam under seismic loading with the damaged plastic model based on the commercial FEM code ABAQUS, a non-linear damping model of gravity dam was proposed. Based on the proposed damping model and constant viscous damping model, three-dimensional seismic response of the gravity dam was evaluated by an iterative numerical method. The calculated results show that the non-linear damping results in a larger dynamic response, and the unsafe results would be obtained with constant damping ratio mode1.