Electron. J. Differential Equations, Vol. 2026 (2026), No. 16, pp. 1-23.

Existence and stability of solutions for a viscoelastic coupled system of two wave equations

Houda Fadel, Djamila Benterki, Salim A. Messaoudi

Abstract:
In this work, we consider the coupled viscoelastic wave system $$\displaylines{ u_{tt} - \Delta u + \int_0^t g(t - s) \Delta u \, ds + \alpha v = 0, \quad \text{in } \Omega \times (0, T), \cr v_{tt} - \Delta v + \alpha u = 0, \quad \text{in } \Omega \times (0, T), \cr u = v = 0, \quad \text{on } \partial \Omega \times (0, T), \\ u(0) = u_0, \quad u_t(0) = u_1, \quad v(0) = v_0, \quad v_t(0) = v_1, \quad \text{in } \Omega, }$$ where \( \Omega \) is a bounded domain in \( \mathbb{R}^N \), \( \alpha > 0 \), and the initial data belong to suitable spaces. The relaxation function \(g \) satisfies \(g'(t) \leq -\xi(t) G(g(t))\), where \(G\) is an increasing and convex function near the origin and \(\xi\) is a non-increasing function. We first prove the well-posedness of the problem, and then we establish a general decay rate of the system energy, highlighting the influence of the relaxation function on the stability of the solutions. Numerical tests were also conducted to validate our theoretical findings.

Submitted September 24, 2025. Published February 19, 2026.
Math Subject Classifications: 35L51, 35B35, 35B40, 49K40, 93D15.
Key Words: Viscoelasticity; energy method; wave equation; general stability.
DOI: 10.58997/ejde.2026.16

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Houda Fadel
Laboratory of Mathematical Analysis and Applications
Department of Mathematics
University Mohamed El Bachir El Ibrahimi
Bordj Bou Arreridj, Algeria
email: houda.fadel@univ-bba.dz
Djamila Benterki
Laboratory of Mathematical Analysis and Applications
Department of Mathematics
University Mohamed El Bachir El Ibrahimi
Bordj Bou Arreridj, Algeria
email: djamila.benterki@univ-bba.dz
Salim A. Messaoudi
Department of Mathematics
College of Sciences
University of Sharjah, Sharjah, UAE
email: smessaoudi@sharjah.ac.ae

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