Interval oscillation criteria for nonlinear second order damped differential equation with distributed delay arguments

By means of the averaging technique and Riccati transformation,We obtain new interval oscillation criteria for certain classes of second order nonlinear damped differential equations with continuous distributed delay arguments. These results are different from most known ones in the sense that they are based on the information only on a sequence of subintervals of [t₀, ∞), rather than on the whole half-line. Our results are sharper than those known in the literature and deal with the cases which are not covered by the known criteria.