Interval oscillation criteria for a forced second-order differential equation with nonlinear damping

In this paper, we are concerned with the oscillations in a class of forced second-order differential equations with nonlinear damping terms. By using an inequality due to Hardy et al., several new interval oscillation criteria for the equations are established. These criteria are different from most known ones in that they are based on the information only on a sequence of subintervals of [t(0), infinity), rather than on the whole half-line. Our results are more general, and extend the oscillation criteria of Wong and Yang. Examples are also given to illustrate the results. (c) 2005 Elsevier Ltd. All rights reserved.