关键词: 螺栓应力;应力幅;在线测量;S-N曲线;水轮发电机组;溪洛渡水电站;

Abstract: In order to further grasp the tightening state of bolts on key parts, and improve the operational reliability of equipment, this paper took Xiluodu Hydropower Station as an example.The bolts stress and its changes on key parts of the spiral casing manhole, draft tube manhole and head cover of hydro-generator set were measured on site during the cases of tightening, water filling, operating and load shedding for the first time in China.The measured results showed that the biggest bolt stress of head cover/stay ring connection bolt and the spiral casing manhole reached 362MPa and 214.8MPa respectively, the bolts stresses were all within the range given by the unit manufacturer.Under all kinds of operating conditions, the variation range of bolts stresses of head cover/stay ring connection bolt, draft tube manhole and the spiral casing manhole reached 3.0MPa, 4.7MPa and 0.64MPa respectively, which all did not exceed the fatigue limit of stress amplitude specified in S-N curve, so the bolts had higher safety margin.The test results are meaningful to the analysis of stress-strain and fatigue life of bolts, and they are also significant to the operation and maintenance of the hydro-generator units.

Key words: on-site measurement; on-line measurement; stress amplitude; bolt stress; S-N curve; hydro-generator unit; Xiluodu Hydropower Station;