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叶片连接状态存在不确定性。基于随机有限元方法,提出了一种随机约束弹性单元用于研究随机约束叶片频率的概率特征,此单元可以模拟自由叶片或成组叶片连接状态的不确定性对叶片频率的影响。推导出了约束刚度随机时的叶片振动特征值方程、频率的均值、频率对约束刚度系数的灵敏度矩阵、频率协方差矩阵、变异系数公式。频率均值表示叶片频率的平均水平,变异系数反映叶片频率的分散程度。通过实例研究了根部约束刚度的随机性对叶片频率的影响。
There is uncertainty in the blade connection status. Based on the stochastic finite element method, a stochastic constrained elastic element is proposed to study the probability of stochastic constrained blade frequency. This element can simulate the influence of the uncertainty of free blade or grouped blade connection on blade frequency. The eigenvalue equation of blade vibration, mean value of frequency, sensitivity matrix of frequency to constraint stiffness coefficient, frequency covariance matrix and coefficient of variation coefficient are deduced. The mean value of the frequency indicates the average level of the leaf frequency, and the variation coefficient reflects the degree of dispersion of the leaf frequency. The influence of randomness of root restraint stiffness on blade frequency is studied through examples.