This article presents a staggered grid time-domain finite-difference (FD) program for the simulation of sH-wave propagation in a viscoelastic heterogeneous medium. The incorporation of realistic damping in FD program is based on a rheological model widely known as generalized maxwell body (gmB-EK). The accuracy of implementation of realistic damping is validated by comparing the numerically com...

A maximal product of stiffness and viscoelastic damping (E tan d), a figure of merit for damping layers, is desirable for structural damping applications. Particulate-reinforced metal–matrix composites were prepared by ultrasonic agitation of the melt and composed of the zinc–aluminum (ZnAl) alloy Zn80Al20 (in wt%) as the lossy matrix and SiC or BaTiO3 as the particulate reinforcements. ZnAl–Si...

Recent developments on the optimization and parameter estimation in hybrid active-passive composite sandwich structures are presented. For this purpose, a mixed layerwise finite element model has been formulated, by considering a higher order shear deformation theory to represent the displacement field in the viscoelastic core and a first order theory for the displacement fields of the adjacent...

We determine the linear viscoelastic response of jammed packings of athermal repulsive viscous spheres, a model for emulsions, wet foams, and soft colloidal suspensions. We numerically measure the complex shear modulus, a fundamental characterization of the response, and demonstrate that low frequency response displays dynamic critical scaling near unjamming. Viscoelastic shear response is gove...

Viscoelastic properties of wet and dry human compact bone were studied in torsion and in bending for both the longitudinal and transverse directions at frequencies from 5 mHz to 5 kHz in bending to more than 50 kHz in torsion. Two series of tests were done for different longitudinal and transverse specimens from a human tibia. Wet bone exhibited a larger viscoelastic damping tan delta (phase be...

Measured by harmonic tests, the viscoelastic properties of Chinese fir during moisture sorption processes were examined under three relative humidity (RH) modes: RHramp, RHisohume, and RHstep. The stiffness decreased and damping increased as a function of the moisture content (MC), which is presumed to be the effect of plasticization and an unstable state. The increasing damping was associated ...

An innovative concept for normalizing the multiple seismic performance objectives of retrofitted structures was recently introduced by the authors. Referred to as a damping-enhanced strengthening, this integrated damping and strengthening strategy included the bonding component between FRP sheets and viscoelastic layers as well as the anchoring component of FRP sheets into concrete. Although an...

In a variety of biomedical engineering applications, cavitation occurs in soft tissue, a viscoelastic medium. The present objective is to understand the basic physics of bubble dynamics in soft tissue. To gain insights into this problem, theoretical and numerical models are developed to study the Rayleigh collapse and subsequent oscillations of a gas bubble in a viscoelastic material. To accoun...

We investigate transmission problems between a (thermo-)viscoelastic system with Kelvin-Voigt damping, and a purely elastic system. It is shown that neither the elastic damping by Kelvin-Voigt mechanisms nor the dissipative effect of the temperature in one material can assure the exponential stability of the total system when it is coupled through transmission to a purely elastic system. The ap...