arXiv subjects

Hai E Zhang

Publications and source records attributed to Hai E Zhang.

2 recordsLinked to original sources

arXiv2023

On the exponential stability of Beck's Problem on a star-shaped graph

We deal with the as yet unresolved exponential stability problem for Beck's Problem on a metric star graph with three identical edges. The edges are stretched Euler--Bernoulli beams which are simply supported with respect to the outer vertices. At the inner vertex we have viscoelastic damping acting on the slopes of the edges. We carry out a complete spectral analysis of the system operator associated with the abstract spectral problem in Hilbert space. Within this framework it is shown that the eigenvectors have the property of forming a Riesz (i.e.\ an unconditional) basis, which makes it possible to directly deduce the exponential stability of the corresponding $C_0$-semigroup using spectral information for the system operator alone. A physically interesting conclusion is that the particular choice of vertex conditions ensures the exponential stability even when the elasticity acting on the slopes of the edges is absent.

math.AP↗

arXiv2023

Decay Rates and Eigenvalue Asymptotics for Abstract Strongly Coupled Hyperbolic Equations with Infinite Memory

In this paper, the asymptotic behavior of abstract strongly coupled hyperbolic equations with one infinite memory term is investigated, one specific case of which is the model for describing the dynamical behaviour of magnetic effected piezoelectric beams. A fractional operator is involved in the memory term depending on the parameter $a\in [0,1)$. By means of frequency domain analysis, it is proved that the system can be indirectly stabilized polynomially by only one infinite memory term located on one of these two strongly coupled PDEs, and the explicit decay rates given as $t^{-\frac{1}{2-2a}}$ are only dependent on the parameter $a$. When considering the exponentially decreasing kernel, a detailed spectral analysis for the system operator is further provided. Specifically, the asymptotic expressions of the eigenvalues of the system operator are derived. Based on the expressions of the eigenvalues, the optimality of the obtained decay rates is further verified for this system.

math.AP↗