This fine paper is devoted to the study of the forced longitudinal vibration of a bar excited by a harmonic force within the frame of linear coupled thermoelasticity. The authors shows that, due to thermomechanical coupling, which results in dissipation of mechanical energy, a unique solution exists for any driving frequency. Furthermore, he investigates the asymptotic behavior of the amplitude functions of displacement and temperature for small values of the coupling parameter. The results presented deserve the interest of researchers in termoelasticity and in wave propagation.