中文摘要：

针对混流式水轮发电机组主轴系统在运行中存在区间参数的情形，运用区间数学表示法表示系统的区间变量，分析系统区间变量的运算特征，确定系统非概率可靠性指标。依据主轴系统激励频率与固有频率之差的绝对值在规定范围内的关系准则，取子功能函数非概率可靠性指标中的最大值作为单失效模式非概率可靠性指标，应用非概率可靠性理论，建立具有相关失效模式的水轮发电机组主轴系统非概率可靠性模型，并通过实例对主轴系统的非概率可靠性进行计算和分析。研究表明：混流式水轮发电机组主轴系统不可靠区域包含不考虑参数有界不确定性的共振点，在共振点的非概率指标都为局部极小值点，即系统在转速为62.1 r/min、82.8 r/min、100.3 r/min和133.8 r/min时最有可能发生共振失效。

英文摘要：

Based on interval mathematics, the interval variables which exist in the main shaft of hy-draulic turbine-generator units are described and the non-probabilistic reliability index of system is determined by analyzing the operation features of the interval variables. According to the criterion that absolute values of difference between natural frequencies and excitation frequencies should be less than specific values, the non-probabilistic reliability model of system based on nonlinear vibra-tion is constructed by the non-probabilistic reliability theory, where the highest non-probabilistic re-liability index is regarded as the non-probabilistic reliability index with single failure mode. The non-probabilistic reliability of the main shaft of hydraulic turbine-generator units is calculated and analyzed with an actual case. The result shows that the main shaft of hydraulic turbine-generator unit contains points of resonance without considering the bounded uncertainties of parameters, and that all the non-probabilistic indices in the point of resonance are local minimum, namely, the possibili-ties of the resonance failure of system at the resonance point are highest when the rotational speed are respectively 62.1 r/min, 82.8 r/min, 100.3 r/min and 133.8 r/min.