Stochastic resonance, reverse-resonance and stochastic multi-resonance in an underdamped quartic double-well potential with noise and delay

► The stochastic resonance in an underdamped delayed bistable system is studied. ► The reverse-resonance transforms into a stochastic resonance. ► The damping coefficient has an optimum value for maximizing the stochastic resonance. ► The emergence of stochastic multi-resonance is observed.