玻璃钢－钢抽油杆柱振动频率的有限元法计算

Finite Element Calculation of Vibrating Frequency of Fiberglass-Steel Sucker Rod Strings

合理设计玻璃钢－钢抽油杆柱，可使该混合杆柱的纵向振动固有频率更接近抽油机的工作频率，实现泵的超行程，从而增加产液量。本文建立了混合杆柱的有阻尼纵向自由振动有限元模型，并采用兰索斯法求解这一多自由度的ＭＣＫ型特征值问题。经实例计算，有限元法比ＡＰＩ计算法和Ｔｒｉｐｐ计算法精确，适用性强，可用于不同类型混合杆柱的设计计算。

Reasonable design of the fiberglass-steel sucker rod string can make the natural longitudinal vibrating frequency of the string still closer to the operating frequency of the pumping unit, thereby increase the produced quantity. The authors establish a finite element model for the longitudinal damped free vibration of the compound string, and work out the characteristic value of multiple degrees of freedom by the Lanczos method. Calculation of an example shows that the finite element method is more accurate than the API method and the Tripp method, and can be used for the design of various kinds of compound sucker rod strings.