修井机井架危险截面部位的结构改进

Improvement of critical cross section of workover rig mast

对进口修井机井架结构进行的有限元分析表明，这种井架最大应力出现在前大腿与天车下第一层门框联结处，其次在大腿与天车联结处。这些部位都是井架的危险截面，其应力几乎高出大腿平均应力的1倍。为了改善危险截面部位的应力状况，分析了产生应力集中的原因，针对这些原因提出几种结构改进方案，并通过分析和比较选出最佳方案，得到了整体应力分布均匀的新井架结构。新结构最大应力比原结构降低30％，设计质量有较大提高。

Finite element analysis of the structure of a workover rig mast shows that the maximum stress is at the connecting area of the front leg and the first window frame under the crown block, and the second maximum stress is at the connecting area of the leg and the crown block. The stress on these areas is twice higher than the mean stress of the mast. The causes of stress concentration at these critical areas are analyzed, several schemes for structure improvement are offered,and the best scheme is selected by means of comparison, and a new mast with reasonable structure and uniform stress distribution is designed. The maximum stress of the new mast is reduced by 30%.