  This study focuses on extending the concept of weak signal enhancement from
dynamical systems based on vibrational resonance of nonlinear systems, to
non-smooth systems. A Van der Pol- Duffing oscillator with a one-sided barrier,
subjected to harmonic excitations, has been considered an archetypical
low-order model, whose response is weak. It is shown that the system response
can be significantly enhanced by applying an additional harmonic excitation but
with much higher frequencies. The reasons for the underlying physics are
investigated analytically using multiple-scale analysis and the Blekham
perturbation approach (direct partition motion). The analytical predictions are
qualitatively validated using numerical simulations. This approach yields
valuable insights into the intricate interplay between fast and slow
excitations in non-smooth systems.
