Large-data regular solutions in a one-dimensional thermoviscoelastic evolution problem involving temperature-dependent viscosities
Michael Winkler
TL;DR
This work analyzes a one-dimensional thermoviscoelastic evolution problem with temperature-dependent viscosity $\gamma(\Theta)$ and nonlinear coupling $f(\Theta)$. By leveraging maximal Sobolev regularity for the parabolic temperature equation and a careful energy plus interpolation framework, it proves global solvability on bounded domains under a small oscillation condition $\gamma_0 \le γ(ξ) \le γ_0+δ$ and subcritical growth $|f(ξ)| \le K_f (ξ+1)^α$ with $α<\frac{3}{2}$, for suitably regular initial data; it also provides global strong solutions under weaker initial data. A key part of the analysis is a loop-type argument that binds $\int_0^T\int_\Omega v_x^4$ and $\int_0^T\int_\Omega (\Theta+1)^{4α}$, using space-time bounds derived from maximal regularity. The results extend the theory of 1D thermo-viscoelastic models with temperature-dependent coefficients, ensuring global well-posedness and regularity even for large data and rough initial conditions.
Abstract
The model \[ \left\{ \begin{array}{l} u_{tt} = \big(γ(Θ) u_{xt}\big)_x + au_{xx} - \big(f(Θ)\big)_x, \\[1mm] Θ_t = Θ_{xx} + γ(Θ) u_{xt}^2 - f(Θ) u_{xt}, \end{array} \right. \] for thermoviscoelastic evolution in one-dimensional Kelvin-Voigt materials is considered. By means of an approach based on maximal Sobolev regularity theory of scalar parabolic equations, it is shown that if $γ_0>0$ is fixed, then there exists $δ=δ(γ_0)>0$ with the property that for suitably regular initial data of arbitrary size an associated initial-boundary value problem posed in an open bounded interval admits a global classical solution whenever $γ\in C^2([0,\infty))$ and $f\in C^2([0,\infty))$ are such that $f(0)=0$ and $|f(ξ)| \le K_f \cdot (ξ+1)^α$ for all $ξ\ge 0$ and some $K_f>0$ and $α<\frac{3}{2}$, and that \[ γ_0 \le γ(ξ) \le γ_0 + δ \qquad \mbox{for all } ξ\ge 0. \] This is supplemented by a statement on global existence of certain strong solutions, particularly continuous in both components, under weaker conditions on the initial data.
