Nonlinear dynamics of discontinuous uncertain oscillators with unilateral constraints.

Nonlinear dynamics of discontinuous oscillators with unilateral constraints and non-random parametric uncertainties are investigated. Nonlinear oscillators considering single- and double-sided constraints are carefully constructed to exhibit rich bifurcations, such as period-doubling and Neimark-Sacker bifurcations. In deterministic amplitude-frequency responses, both hardening and softening effects are induced by non-smooth contact-type nonlinearities.