基于ABAQUS三维有限元软件在新疆某水电站主厂房干扰振源共振复核分析的研究与应用

Research and Application of ABAQUS Three-Dimensional Finite Element Software in Resonance Recheck Analysis of Interference Vibration Source of Powerhouse of a Hydropower Station in Xinjiang

水电站主厂房是由下部的大体积混凝土与上部框架等结构组成的综合体,该结构内部有蜗壳、尾水管、机墩、风罩、水下墙和各层板梁等,结构形式十分复杂,传统的结构力学法难以反映结构实际的受力状态和变形情况。结合新疆某大型水利枢纽工程中的水电站主厂房,采用ABAQUS三维有限元软件中的Lanczos方法,提取主厂房结构的前30阶振动频率和振型,与运行期机组干扰振源频率进行共振复核分析。成果表明:低频区与高频区的错开度都大于30%,基本不会发生共振的危险。中频区与飞逸工况发生共振的可能性较低。厂房上部框架结构的刚度较低,其固有频率与机组转速频率错开度小,建议将上部结构更改为框架剪力墙结构,以便达到增大上述变形刚度的目的。

The powerhouse of hydropower station is a complex composed of mass concrete in the lower part and frame in the upper part which accommodates spiral case,draft tube,turbine pier,wind cover,underwater wall and slab beams etc.The traditional structural mechanics method is difficult to reflect the actual stress state and deformation of the structure.Taking the powerhouse of a hydropower station in Xinjiang as an example,based on the Lanczos method of ABAQUS three-dimensional finite element software,the first 30 vibration frequencies and modes of the powerhouse structure are extracted,and the resonance check analysis is carried out with the interference vibration source frequency of the unit during the operation period.The results show that the stagger degrees in low frequency region and high frequency region are both over 30%,and there is no risk of resonance.The possibility of resonance in mid frequency region and under runaway condition is low.The rigidity of the upper frame structure of the powerhouse is relatively low,and its natural frequency is less staggered with the unit speed frequency.It is suggested the upper structure be transformed to the frame shear wall structure,so as to achieve the purpose of increasing the above mentioned deformation rigidity.