基于接触单元的三峡电站厂房振动分析

Analysis on the vibration of Three Gorges hydropower house on the basis of double-node contact elements

如何合理分析蜗壳和外围钢筋混凝土之间的传力特性,是大型水电站厂房设计和研究的难点之一。本文针对三峡左岸电站VGS机组的厂房结构,采用双结点接触非线性模型,计算混凝土结构以及蜗壳、座环和固定导叶的振动响应。为了便于对比分析,建立共结点模型并开展相应的计算分析。计算结果表明,对于混凝土结构而言,两种模型的振动响应分布规律基本一致,接触模型的位移响应幅值与共结点模型基本吻合,但加速度响应明显小于共结点模型;对于蜗壳、座环和固定导叶,接触模型的各种振动响应明显大于共结点模型,这主要是由于接触模型中外围混凝土对蜗壳的约束相对较小,由此说明接触模型能更为合理地模拟实际结构的真实传力特征。

As for design and research on large-scale hydropower house, it＇s one of difficult points how to rationally analyze the stress state of the interface between spiral case and reinforced concrete. The VGS powerhouse of Three Gorges hydropower station is taken as engineering background in this paper, the double-node contact element is adopted to simulate the interface, then the vibration responses of reinforced concrete structure, as well that of spiral case, seating ring and stay guide vane, are solved. For the sake of contrastive analysis, a common-node model is built, and the corresponding research is carried out. The computation results show that： （1） as far as the vibration responses of concrete structure are concerned, the displacement amplitude of contact nonlinear common-node model is close to that of common-node model, and the vibration responses are accordant basically to each other, while the acceleration of the linear common-node model exceeds obviously that of the contact model; （2） as for spiral case, seating ring and stay guide vane, because the reinforced concrete applies relatively less restraint force to the spiral case in contact model, its vibration response is more evident than that of the common-node model, so the contact model is more rational to simulate the contact interface of actual structure.