基于能量原理的单层网壳结构动力损伤分析

Analysis of dynamic damage on single layer latticed domes based on energy principle

为了建立适用性更为广泛的地震损伤动力分析模型,将损伤理论与能量原理相结合,提出以塑性耗能指标增长率为依据的结构输入地震波合理地震持时的判断方法。分别采用理想弹塑性和应变-损伤耦合本构模型,对一典型六角星型穹顶和单层球面网壳结构进行动力增量分析,分析不同持时地震作用下结构最大位移、承载力、损伤指数、塑性杆件发展比例、塑性耗能分配等变化规律,验证能量计算方法的可靠性。结果表明,地震持时过短将出现高估结构动力承载力和低估结构塑性发展程度等不安全隐患。合理持时地震作用下结构的损伤指数和塑性耗能指标可用来衡量结构整体和局部塑性损伤破坏状态。

Aiming at setting up a dynamic analytical model for earthquake-induced damages with wider applicability, a reasonable judgement method of ground motion duration was presented based on the rate of increment of plastic dissipation energy indicator, which combined energy principle with damage theory. Utilizing respectively the ideal elasto-plastic constitutive model and the constructive relationship between strain and damage, the maximum displacement, ultimate load carrying capacity, damage index, developmental proportion of plastic bars, and distribution of plastic dissipation energy and so on under different ground motion durations were analyzed through the dynamic increment analysis method for both the hexagonal domes and the single-layer latticed domes. The reliability of energy method was verified. The results indicate that damage accumulation effects on structures should be taken into account due to ground motion duration. If the ground motion duration is shorter, then the structure may be unsafe due to overestimated load carrying capacity and underestimated plastic development degree. Under the action of rational ground motion duration, the structural global and local plastic damage conditions can be scaled by the structural damage index and plastic dissipation energy indicator separately.