We investigate the long time behavior of solutions to semilinear hyperbolic equation (E$_{ \alpha}$): $ u^{ \prime\prime}(t)+\gamma(t)u^{ \prime}(t)+Au(t)+f(u(t))=g(t),~t\geq0, $ where $A$ is a self-adjoint nonnegative operator, $f$ a function which derives from a convex function, and $\gamma$ a nonnegative function which behaviors, for $t$ large enough, as $\frac{ K}{ t^{ \alpha}}$ with $K>0$ and $\alpha \in\lbrack0,1[.$ We obtain sufficient conditions on the source term $g(t),$ ensuring the weak or the strong convergence of any solution $u(t)$ of (E$_{ \alpha}$) as $t\rightarrow+\infty$ to a solution of the stationary equation $Av+f(v)=0$ if one exists.
Categories: math.OC