Abstract: For the frequency response of complex mechanical structures with random parameters， the frequency reliability was defined and an efficient method to compute the frequency reliability and reliability sensitivity was proposed. The stochastic response surface was employed to approximate the relationship between input variables and natural frequency. Dimension reduction integral was utilized to compute the coefficients of the stochastic response surface expansion. In order to alleviate the computational burden of structural reanalysis， a kind of model order reduction technique was applied. The AFOSM (advanced first order second moment) method was utilized to evaluate the frequency reliability and the reliability sensitivity was obtained by the Monte Carlo simulation. The numerical examples demonstrate the efficiency and accuracy of the method for complex structures.

Key words: frequency reliability, reliability sensitivity, stochastic response surface, dimension reduction integral, model order reduction