Asymptotic analysis of axially accelerating viscoelastic strings

An asymptotic approach is proposed to investigate nonlinear parametric vibration of axially accelerating viscoelastic strings. The string is constituted by the Kelvin model with the material time derivative. Both the Mote model and the Kirchhoff model of transverse motion are analyzed via the asymptotic approach in principal parametric resonance. The modulation equation is derived from the solvability condition. Closed-form expressions of the amplitudes and the existence conditions of steady-state responses are solved from the modulation equation. Numerical results are presented to highlight the effects the initial stress, the parameters in the Kelvin model, and the axial speed fluctuation amplitude on the amplitudes and the existence conditions of steady-state responses.