SIAM Journal on Control and Optimization, Vol.52, No.1, 545-580, 2014
UNIFORM DECAY RATES FOR THE WAVE EQUATION WITH NONLINEAR DAMPING LOCALLY DISTRIBUTED IN UNBOUNDED DOMAINS WITH FINITE MEASURE
This paper is concerned with the study of the uniform decay rates of the energy associated with the wave equation with nonlinear damping locally distributed u(tt) - Delta u + a(x) g(u(t)) = 0 in Omega x (0, infinity) subject to Dirichlet boundary conditions where Omega subset of R-n n >= 2 is an unbounded open set with finite measure and unbounded smooth boundary partial derivative Omega = Gamma. The function a(x), responsible for the localized effect of the dissipative mechanism, is assumed to be nonnegative and essentially bounded and, in addition, a (x) >= a(0) > 0 a. e. in omega, where omega = omega' boolean OR {x is an element of Omega; parallel to x parallel to| > R} (R > 0) and omega' is a neighborhood in Omega of the closure of partial derivative Omega boolean AND B-R, where B-R = {x is an element of Omega; parallel to x parallel to < R}.