Arbitrary decays for a viscoelastic equation
Boundary Value Problems volume 2011, Article number: 28 (2011)
In this paper, we consider the nonlinear viscoelastic equation , in a bounded domain with initial conditions and Dirichlet boundary conditions. We prove an arbitrary decay result for a class of kernel function g without setting the function g itself to be of exponential (polynomial) type, which is a necessary condition for the exponential (polynomial) decay of the solution energy for the viscoelastic problem. The key ingredient in the proof is based on the idea of Pata (Q Appl Math 64:499-513, 2006) and the work of Tatar (J Math Phys 52:013502, 2010), with necessary modification imposed by our problem.
Mathematical Subject Classification (2010): 35B35, 35B40, 35B60
It is well known that viscoelastic materials have memory effects. These properties are due to the mechanical response influenced by the history of the materials themselves. As these materials have a wide application in the natural sciences, their dynamics are of great importance and interest. From the mathematical point of view, their memory effects are modeled by an integro-differential equations. Hence, questions related to the behavior of the solutions for the PDE system have attracted considerable attention in recent years. Many authors have focused on this problem for the last two decades and several results concerning existence, decay and blow-up have been obtained, see [1–28] and the reference therein.
In , Cavalcanti et al. studied the following problem
where Ω ⊂ RN, N ≥ 1, is a bounded domain with a smooth boundary ∂Ω, γ ≥ 0, if N ≥ 3 or ρ > 0 if N = 1, 2, and the function g: R+ → R+ is a nonincreasing function. This type of equations usually arise in the theory of viscoelasticity when the material density varies according to the velocity. In that paper, they proved a global existence result of weak solutions for γ ≥ 0 and a uniform decay result for γ > 0. Precisely, they showed that the solutions goes to zero in an exponential rate for γ > 0 and g is a positive bounded C1-function satisfying
for all t ≥ 0 and some positive constants ξ1 and ξ2. Later, this result was extended by Messaoudi and Tatar  to a situation where a nonlinear source term is competing with the dissipation terms induced by both the viscoelasticity and the viscosity. Recently Messaoudi and Tatar  studied problem (1.1) for the case of γ = 0, they improved the result in  by showing that the solution goes to zero with an exponential or polynomial rate, depending on the decay rate of the relaxation function g.
The assumptions (1.2) and (1.3), on g, are frequently encountered in the linear case (ρ = 0), see [1, 2, 4–6, 13, 22, 23, 29–31]. Lately, these conditions have been weakened by some researchers. For instance, instead of (1.3) Furati and Tatar  required the functions eαt g(t) and eαtg'(t) to have sufficiently small L1-norm on (0, ∞) for some α > 0 and they can also have an exponential decay of solutions. In particular, they do not impose a rate of decreasingness for g. Later on Messaoudi and Tatar  improved this result further by removing the condition on g'. They established an exponential decay under the conditions g'(t) ≤ 0 and eαt g(t) ∈ L1(0, ∞) for some large α > 0. This last condition was shown to be necessary condition for exponential decay . More recently Tatar  investigated the asymptotic behavior to problem (1.1) with ρ = γ = 0 when h(t)g(t) ∈ L1(0, ∞) for some nonnegative function h(t). He generalized earlier works to an arbitrary decay not necessary of exponential or polynomial rate.
with initial conditions
and boundary condition
where Ω ⊂ RN, N ≥ 1, is a bounded domain with a smooth boundary ∂Ω. Here ρ, p > 0 and g represents the kernel of the memory term, with conditions to be stated later [see assumption (A1)-(A3)].
We intend to study the arbitrary decay result for problem (1.4)-(1.6) under the weaker assumption on g, which is not necessarily decaying in an exponential or polynomial fashion. Indeed, our result will be established under the conditions g'(t) ≤ 0 and for some nonnegative function ξ(t). Therefore, our result allows a larger class of relaxation functions and improves some earlier results concerning the exponential decay or polynomial decay.
The content of this paper is organized as follows. In Section 2, we give some lemmas and assumptions which will be used later, and we mention the local existence result in Theorem 2.2. In Section 3, we establish the statement and proof of our result related to the arbitrary decay.
2 Preliminary results
In this section, we give some assumptions and lemmas which will be used throughout this work. We use the standard Lebesgue space Lp(Ω) and Sobolev space with their usual inner products and norms.
Lemma 2.1. (Sobolev-Poincaré inequality) Let , the inequality
holds with the optimal positive constant c s , where || · || p denotes the norm of Lp(Ω).
Assume that ρ satisfies
With regards to the relaxation function g(t), we assume that it verifies
(A1) g(t) ≥ 0, for all t ≥ 0, is a continuous function satisfying
(A2) g'(t) ≤ 0 for almost all t > 0.
(A3) There exists a positive nondecreasing function ξ(t): [0, ∞) → (0, ∞) such that is a decreasing function and
Theorem 2.2. Suppose that (2.1) and (A1) hold, and that . Assume , if N ≥ 3, p > 0, if N = 1, 2. Then there exists at least one global solution u of (1.4)-(1.6) satisfying
Next, we introduce the modified energy functional for problem (1.4)-(1.6)
Lemma 2.3. Let u be the solution of (1.4)-(1.6), then the modified energy E(t) satisfies
Proof. Multiplying Eq. (1.4) by u t and integrating it over Ω, then using integration by parts and the assumption (A1)-(A2), we obtain (2.6).
Remark. It follows from Lemma 2.3 that the energy is uniformly bounded by E(0) and decreasing in t. Besides, from the definition of E(t) and (2, 2), we note that
3 Decay of the solution energy
In this section, we shall state and prove our main result. For this purpose, we first define the functional
where λ i are positive constants, i = 1, 2, 3 to be specified later and
Remark. This functional was first introduced by Tatar  for the case of ρ = 0 and without imposing the dispersion term and forcing term as far as (1.4) is concerned.
The following Lemma tells us that L(t) and E(t) + Φ3(t) are equivalent.
Lemma 3.1. There exists two positive constants β1 and β2 such that the relation
holds for all t ≥ 0 and λ i small, i = 1, 2.
Proof. By Hölder inequality Young's inequality Lemma 2.1, (2.7) and (2.2), we deduce that
where . Therefore, from above estimates, the definition of E(t) by (2.4) and (2.2), we have
where , , and . Hence, selecting λ i , i = 1, 2 such that
and again from the definition of E(t), there exist two positive constants β1 and β2 such that
To obtain a better estimate for , we need the following Lemma which repeats Lemma 2 in .
Lemma 3.2. For t ≥ 0, we have
Proof. Straightforward computations yield this identity.
The flatness set and the flatness rate of g are defined by
Before proceeding, we note that there exists t0 > 0 such that
since g is nonnegative and continuous.
Theorem 3.3. Let be given. Suppose that (A1)-(A3), (2, 1) and the hypothesis on p hold. Assume further that , and with
Then the solution energy of (1.4)-(1.6) satisfies
where μ and K are positive constants.
Proof. In order to obtain the decay result of E(t), it suffices to prove that of L(t). To this end, we need to estimate the derivative of L(t). It follows from (3.2) and Eq. (1.4) that
which together with the identity (3.6) and (2.2) gives
Next, we would like to estimate . Taking a derivative of Φ2 in (3.3) and using Eq. (1.4) to get
We now estimate the first two terms on the right-hand side of (3.11) as in .
Indeed, for all measure set A and F such that A = R+ - F, we have
To simplify notations, we denote
Using Hölder inequality Young's inequality and (2.2), we see that, for δ1 > 0,
Thus, from the definition of by (3.8), (3.12) becomes
The second term on the right-hand side of (3.11) can be estimated as follows (see ), for δ2 > 0,
Using Hölder inequality Young's inequality and (A2) to deal with the fifth term, for δ3 > 0,
Exploiting Hölder inequality Young's inequality Lemma 2.1 and (A2) to estimate the sixth term, for δ4 > 0,
For the last term, thanks to Hölder inequality Young's inequality Lemma 2.1, (2.7), (2.2) and (3.8), we have, for δ5 > 0,
where . Thus, gathering these estimates (3.13)-(3.17) and using (3.9), we obtain, for t ≥ t0,
Further, taking a derivative of Φ3(t), using the fact that is a decreasing function and the definition of Φ3(t) by (3.4), we derive that (see )
Hence, we conclude from (2.6), (3.10), (3.18) and (3.19) that for any t ≥ t0 > 0,
and observe that
where F g is given in (3.7) and N g is the null set where g' is not defined. In addition, denoting F n = R+ - A n , then
because A n are increasingly nested. Thus, choosing A = A n , F = F n and λ1 = (g * - ε) λ2 for some ε > 0 in (3.20), we obtain
At this point, we take and select λ2 so that
then (3.21) becomes
For ε, δ2 small enough and large value of n and t0, we see that if
Note that α > 0 and 0 < δ < 1 due to . Furthermore, we require λ2 and λ3 satisfying
this is possible because of . Then, letting δ1 be small enough and using (3.22), we see that
Hence, from the definition of E(t) by (2.4), we have, for all t ≥ t0,
for some positive constant c4. As η(t) is decreasing, we have η(t) ≤ c4 after some t* ≥ t0. Hence, with the help of the right hand side inequality in (3.5), we find
for some positive constant c5 > 0. An integration of (3.23) over (t*, t) gives
Then using the left hand side inequality in (3.5) leads to
Therefore, by virtue of the continuity and boundedness of E(t) and ξ(t) on the interval [0, t*], we infer that
for some positive constants K and μ.
Similar to those remarks as in , we have the following remark.
Remark. Note that there is a wide class of relaxation functions satisfying (A3). More precisely, if ξ(t) = eαt, α > 0, then η(t) = α, this gives the exponential decay estimate , for some positive constants c1 and c2. Similarly, if ξ(t) = (1 + t)α , α > 0, then we obtain the polynomial decay estimate E (t) ≤ c3 (1 + t)-μ, for some positive constants c3 and μ.
Berrimi S, Messaoudi SA: Existence and decay of solutions of a viscoelastic equation with a nonlinear source. Nonlinear Anal Theory Methods Appl 2006, 64: 2314-2331. 10.1016/j.na.2005.08.015
Berrimi S, Messaoudi SA: Exponential decay of solutions to a viscoelastic equation with nonlinear localized damping. Electron J Diff Equ 2004, 88: 1-10.
Cavalcanti MM, Domingos Cavalcanti VN, Ferreira J: Existence and uniform decay of nonlinear viscoelastic equation with strong damping. Math Methods Appl Sci 2001, 24: 1043-1053. 10.1002/mma.250
Cavalcanti MM, Domingos Cavalcanti VN, Soriano JA: Exponential decay for the solution of semilinear viscoelastic wave equation with localized damping. Electron J Diff Equ 2002, 44: 1-14.
Cavalcanti MM, Domingos Cavalcanti VN, Prates Filho JS, Soriano JA: Existence and uniform decay rates for viscoelastic problems with nonlinear boundary damping. Diff Integr Equ 2001, 14(1):85-116.
Cavalcanti MM, Oquendo HP: Frictional versus viscoelastic damping in a semilinear wave equation. SIAM J Control Optim 2003, 42(4):1310-1324. 10.1137/S0363012902408010
Fabrizo M, Polidoro S: Asymptotic decay for some differential systems with fading memory. Appl Anal 2002, 81: 1245-1264. 10.1080/0003681021000035588
Furati K, Tatar N-e: Uniform boundedness and stability for a viscoelastic problem. Appl Math Comput 2005, 167: 1211-1220. 10.1016/j.amc.2004.08.036
Han X, Wang M: Global existence and uniform decay for a nonlinear viscoelastic equation with damping. Nonlinear Anal Theory Methods Appl 2009, 70: 3090-3098. 10.1016/j.na.2008.04.011
Kawashima S, Shibata Y: Global existence and exponential stability of small solutions to nonlinear viscoelasticity. Commun Math Phys 1992, 148: 189-208. 10.1007/BF02102372
Kirane M, Tatar N-e: A memory type boundary stabilization of a mildy damped wave equation. Electron J Qual Theory Diff Equ 1999, 6: 1-7.
Liu WJ: General decay rate estimate for a viscoelastic equation with weakly nonlinear time-dependent dissipation and source terms. J Math Phys 2009, 50: 113506. 10.1063/1.3254323
Medjden M, Tatar N-e: Asymptotic behavior for a viscoelastic problem with not necessarily decreasing kernel. Appl Math Comput 2005, 167: 1221-1235. 10.1016/j.amc.2004.08.035
Messaoudi SA, Tatar N-e: Exponential and polynomial decay for quasilinear viscoelastic equation. Nonlinear Anal Theory Methods Appl 2007, 68: 785-793.
Messaoudi SA, Tatar N-e: Global existence and asymptotic behavior for a nonlinear viscoelastic problem. Math Sci Res J 2003, 7(4):136-149.
Messaoudi SA, Tatar N-e: Global existence and uniform stability of solutions for a quasilinear viscoelastic problem. Math Methods Appl Sci 2007, 30: 665-680. 10.1002/mma.804
Messaoudi SA: Blow-up and global existence in a nonlinear viscoelastic wave equation. Math Nachr 2003, 260: 58-66. 10.1002/mana.200310104
Messaoudi SA: Blow-up of positive-initial-energy solutions of a nonlinear viscoelastic hyperbolic equation. J Math Anal Appl 2006, 320: 902-915. 10.1016/j.jmaa.2005.07.022
Messaoudi SA: General decay of the solution energy in a viscoelastic equation with a nonlinear source. Nonlinear Anal Theory Methods Appl 2008, 69: 2589-2598. 10.1016/j.na.2007.08.035
Messaoudi SA: General decay of solutions of a viscoelastic equation. J Math Anal Appl 2008, 341: 1457-1467. 10.1016/j.jmaa.2007.11.048
Messaoudi SA, Tatar N-e: Exponential decay for a quasilinear viscoelastic equation. Math Nachr 2009, 282: 1443-1450. 10.1002/mana.200610800
Munoz Rivera JE, Lapa EC, Baretto R: Decay rates for viscoelastic plates with memory. J Elast 1996, 44: 61-87. 10.1007/BF00042192
Nečas MJ, Šverák V: On weak solutions to a viscoelasticity model. Comment Math Univ Carolin 1990, 31(3):557-565.
Pata V: Exponential stability in linear viscoelasticity. Q Appl Math 2006, 64: 499-513.
Tatar N-e: Arbitrary decay in linear viscoelasticity. J Math Phys 2010, 52: 013502.
Wu ST: Blow-up of solutions for an integro-differential equation with a nonlinear source. Electron J Diff Equ 2006, 45: 1-9.
Wu ST: General decay of solutions for a viscoelastic equation with nonlinear damping and source terms. Acta Math Sci 2011, 31(4):1436-1448.
Wu ST: General decay of energy for a viscoelastic equation with linear damping and source term. Taiwan J Math, in press.
Hrusa WJ: Global existence and asymptotic stability for a nonlinear hyperbolic Volterra equation with large initial data. SIAM J Math Anal 1985, 16: 110-134. 10.1137/0516007
Medjden M, Tatar N-e: On the wave equation with a temporal nonlocal term. Dyn Syst Appl 2007, 16: 665-672.
Tiehu Q: Asymptotic behavior of a class of abstract integrodifferential equations and applications. J Math Anal Appl 1999, 233: 130-147. 10.1006/jmaa.1999.6271
The authors would like to thank very much the anonymous referees for their valuable comments on this work.
The author declares that they have no competing interests.
About this article
Cite this article
Wu, ST. Arbitrary decays for a viscoelastic equation. Bound Value Probl 2011, 28 (2011). https://doi.org/10.1186/1687-2770-2011-28