“…In a fixed domain, it is well known that the energy of the system (1.2) also decays to zero, see [8,13]. But in a moving domain, see [2,[5][6][7]17], energy decay were more difficult to obtain than the result in fixed domain. And in this case, the transverse deflection u(x, t) of a beam which changed its configuration at each instant of time increases its deformation, and hence increases its tension.…”