summary:In this paper, we consider the following initial-boundary value problem
{\left\rbrace \begin{array}{ll} u_{tt}(x,t)=\varepsilon Lu(x,t)+f\big (u(x,t)\big )\quad \mbox {in}\quad \Omega \times (0,T)\,,\\ u(x,t)=0 \quad \mbox {on}\quad \partial \Omega \times (0,T)\,, \\ u(x,0)=0 \quad \mbox {in}\quad \Omega \,, \\ u_t(x,0)=0 \quad \mbox {in}\quad \Omega \,, \end{array}\right.}
where Ω is a bounded domain in RN with smooth boundary ∂Ω, L is an elliptic operator, ε is a positive parameter, f(s) is a positive, increasing, convex function for s∈(−∞,b), lims→bf(s)=∞ and ∫0bf(s)ds0. Under some assumptions, we show that the solution of the above problem quenches in a finite time and its quenching time goes to that of the solution of the following differential equation
}α′′(t)=f(α(t)),α(0)=0,α′(0)=0,t>0,
as ε goes to zero. We also show that the above result remains valid if the domain Ω is large enough and its size is taken as parameter. Finally, we give some numerical results to illustrate our analysis