Asymptotic solutions of the problem of dynamics of an infinitely long string lying on an elastic base with prescribed damage under the action of finitely many periodic impacts are constructed in the two cases of small and large damage of the elastic base. The condition of resonance origination in the string is obtained in the case of small damage when the standing wave is localized in the region of damage. At the final stage of the damage growth in the elastic base, when its value is close to the critical one, the localized mode and the resonance are absent, and only a traveling wave exists in the string.