水力发电厂起重机械是用于起吊转子和闸门等大型零部件的关键特种设备, 主要支撑部分为金属结构, 一般为非标准设计, 结构庞大, 利用超声或射线等常规无损检测技术很难对它们进行全面有效的定期检测。探讨了利用声发射技术对其进行检测的可行性, 通过对带裂纹缺陷的金属结构加载试验, 采集活性缺陷发生发展的声发射信号。应用统计参数方法分析, 提出评价裂纹缺陷的活度和强度的定量指标, 进而定量评定出在役裂纹缺陷的危险性, 为重大机械的定检和安全评价提供理论指导和试验数据。

In hydropower station lifting machines are a key specific device, which are used to lift the heavy parts, such as turbine rotor, draw-gate. Lifting machines are very large and heavy, the main supporting structures are made of metal and by non-standard design. It is difficult to perform routine examinations using conventional nondestructive testing technology such as ultrasonic and radiographic testing. Thus, an alternative method, the acoustic emission(AE) technology was introduced to test active cracks in the structures of lifting machines. The AE signals of in-service defect were collected from a load-bearing metal beam with seeded cracks. Based on statistic parameter analysis, two quantitative indexes were proposed to assess the activity and intensity of active cracks. Furthermore, the hazard degree of the defect could be evaluated. The method could provide both theoretical guide and experimental data for the routine examination and safety evaluation of large and heavy machine.