Asymptotic behaviour of solutions is studied for some second order equations including the model case (x)(t) +γx(t) +▽Φ(x(t)) =h(t) with γ ＞ 0 and h ∈ L1(0,+∞; H),Φ being continuouly differentiable with locally Lipschitz continuous gradient and bounded from below.In particular when Φ is convex,all solutions tend to minimize the potential Φ as time tends to infinity and the existence of one bounded trajectory implies the weak convergence of all solutions to equilibrium points.