Purpose - The purpose of this paper is to present numerical studies on thermally induced vibrations of piezo-thermo-viscoelastic composite beam subjected to a transient thermal load using coupled finite element method. Design/methodology/approach - The thermal relaxation and viscoelastic relaxations are taken into consideration to obtain the system response. The concept of "memory load" along with the thermal relaxation is accounted for viscoelastic core material. The influence of type of core material on the response of the system also analyzed. Findings - The findings show viscoelastic behavior with relaxation times in composite sandwich structures. Originality/value - The paper shows accounting relaxation times as a memory load in composite sandwich structures. © Emerald Group Publishing Limited.