水电站厂房上部结构耦联动力特性及其设计优化分析

Coupling dynamic characteristics and design optimization analysis of the roof truss of powerhouse of hydropower station

水电站地面厂房上部结构较单一薄弱,刚度较低,是动力设计应关注的重点之一。在水电站厂房设计规范中,重点关注机墩的振动问题,而对上部结构动力复核尚无规定。常规计算模型一般将屋架简化为刚性二力杆,很少模拟实际屋架结构,且屋架与立柱支座的连接模拟也是很复杂的问题。结合某工程实例,利用有限元分析软件ANSYS建立了厂房整体模型,进而分别建立屋架模型、屋架与支承结构的耦联模型,对2种屋架形式及3种支座连接传力方式进行了数值模拟和振动特性对比分析。结果表明,空间屋架结构在一定程度上提高了上部结构的刚度,在动力荷载作用下使厂房整体最大动位移有所减小;支座连接处理时采用简支方案会使厂房上部结构刚度相对变低,但厂房整体结构抗振性能表现更好,简支方案模拟是适用的。

The upper structure of the hydropower station is relatively weak and has low stiffness,which is one of the focuses of dynamic design.In the design specification of hydropower station,the focus is on the vibration problem of the pier,but there is no regulation on the vibration review of the upper structure,and the roof truss is generally simplified into a rigid two force bars in the model.The example of a hydropower project are used,and the finite element analysis software ANSYS is used to establish the overall model of the plant,the coupling model of the roof truss model,the roof truss and the support structure are established respectively.With the two roof truss forms and the three types of connection methods,numerical simulation and comparative analysis of vibration characteristics are carried out.The results show that the space grid structure improves the stiffness of the upper structure to a certain extent,and the maximum dynamic displacement of the whole plant is small under the dynamic load;the simple support scheme will make the upper structure stiffness of the plant relatively low.However,the overall structure of the plant has better vibration resistance performance,and the simple support scheme simulation is applicable.