In this paper, we investigated the temperature-dependent viscoelastic behavior of dielectric elastomers (DEs) and the effects of viscoelasticity on the electro-actuation behavior. We performed dynamic thermomechanical analysis to measure the master curve of the stress relaxation function and the temperature dependence of the relaxation time of VHB 4905, a commonly used DE. The master curve was ...

Recoverable creep compliance JR(t) was analytically calculated for polymer chains relaxing through the Rouse and reptation mechanisms at short and long time scales, respectively. The ratio of the longest relaxation times of these mechanisms, rτ = τRouse/τrep, was varied from 0.056 to 0.0033. The calculation indicated that the effect of the fast Rouse mechanism on the distribution of slow modes ...

We study the effect of physical aging on the mechanical properties of a model polymer glass using molecular dynamics simulations. The creep compliance is determined simultaneously with the structural relaxation under a constant uniaxial load below yield at constant temperature. The model successfully captures universal features found experimentally in polymer glasses, including signatures of me...

The goal of this study was to determine the duration of time that ligaments from a study group need to be loaded in order to adequately determine their collective viscoelastic behavior. Rat ligaments were subjected either to creep or stress relaxation for 1,000 s or stress relaxation for 10,000 s to compare estimates of viscoelastic behavior for different test durations. Stresses versus time (r...

The pressure probe was used to conduct in vivo creep and in vivo stress relaxation experiments on the sporangiophores of Phycomyces blakesleeanus. The in vivo creep and in vivo stress relaxation methods are compared with respect to their utility for determining the irreversible wall extensibility and the yield threshold. The results of the in vivo stress relaxation experiments demonstrate that ...

M untz theorems from classical approximation theory are used to lay the mathematical foundation for the discrete spectral representations of the relaxation modulus and creep compliance. Algorithms that can automatically generate nonnegative discrete relaxation and retardation strength are formulated by using the nonnegative least square method.

Recent work in the creep field has indicated that the traditional methodologies involving power law equations are not sufficient to describe wide ranging creep behaviour. More recent approaches such as the Wilshire equations however, have shown promise in a wide range of materials, particularly in extrapolation of short term results to long term predictions. In the aerospace industry however, l...

Abstract: The mathematical foundation of many real-world problems can be quite deep. Such a situation arises in the study of the flow and deformation (rheology) of viscoelastic materials such as naturally occurring and synthetic polymers. In order to advance polymer science and the efficient manufacture of synthetic polymers, it is necessary to recover information about the molecular structure ...

Rheological behavior of high-density polyethylene (HDPE)-wood flour composites with different wood contents was examined using steady shear sweep, oscillatory frequency sweep, creep test, and stress relaxation test. The samples were prepared using a melt compounding method in a twin-screw extruder. The results showed that the yield stress did not appear for the composites prepared under the pro...