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For shape memory alloy (SMA) oscillator, the stochastic transitions between low-amplitude and undesirable high-amplitude oscillations will affect the safety and normal use of the system. Therefore, the nonlinear dynamical responses of a SMA oscillator with both periodic and Gaussian colored noise excitations are investigated in this paper. Firstly, to reveal the influences of random factors, a stochastic SMA model with a Gaussian colored noise is introduced. Subsequently, the approximate analytical solution of the steady-state amplitude response under the deterministic case is given by the averaging method, and the time-averaging mean-square response of the stochastic SMA system is obtained by the stochastic averaging method. The deduced approximated analytical solutions are verified by Monte Carlo numerical results, and a good consistency is observed. Finally, the effects of the random excitation and temperature on the steady-state responses of the SMA system are explored. We uncover that the temperature influences the frequency of bifurcation points, which can disrupt the stable structure of the SMA oscillator. In addition, noise intensity and correlation time of the colored noise can induce the occurrence of stochastic transitions between low-amplitude and high-amplitude oscillations, which are visible through the steady-state probability density and time history diagrams. All these obtained results may provide theoretical guidance and valuable insights for avoiding catastrophic stochastic transitions in SMA materials. • The dynamical responses of a SMA oscillator excited by colored noise are studied theoretically and numerically. • Exploring the stochastic transitions phenomena and the effects of colored noise on SMA oscillator. • Provide theoretical guidance for the reliability and safety design of the SMA system. [ABSTRACT FROM AUTHOR]