Abstract: The Workbench software was used to establish a parametric finite element model of the torque shaft. Through modal analysis and comparison with the transfer matrix method， the first six orders of natural frequency and corresponding limit speed were obtained to verify the rationality of the structure and speed design. The harmonic response analysis illustrated that resonance invalidation should consider the first natural frequency. In addition， the response surface design and Latin superpower square sampling methods were used to realize the sampling analysis of the structure and material parameters. The BP neural network technology was used to fit the functions of first order natural frequency， solving the reliability sensitivity of each random parameter. The first order second moment and Monte-Carlo simulation were used to calculate the reliability at a specific speed and to find out the biggest influencing factor on the dynamic reliability， thus laying a foundation for the robust optimization design of shaft.

Key words: torque shaft, finite element, BP neural network, reliability, reliability sensitivity