We use a Lagrangian finite element method to simulate experiments on continued and interrupted extensions of a highly entangled monodisperse polymer melt. It is demonstrated that delayed sample necking or rupture may be explained in terms of the original Doi-Edwards model augmented by the mechanism of chain stretching alone.

We investigate the transient viscoelastic response of weakly strain-hardening fluids to imposed elongational deformation in filament stretching devices. We combine timedependent finite-element simulations with quantitative experimental measurements on a rheologically well-characterized test fluid to investigate how well the device reproduces the ideal transient uniaxial extensional viscosity pr...

It follows from the Chapter 7 that, except for very short gauge lengths, percent elongation is mainly influenced by uniform elongation, and is thus dependent upon the strain-hardening capacity of the matrix. In contrast, reduction in area is more a measure of the deformation required to produce fracture, and its chief contribution arises from the necking process. The work of Groom (1971) illust...

leishmaniasis include several clinical manifestations, mostly cutaneous, visceral and mucosal (1, 2). various species can lead to diverse clinical presentations. thus species identification contribute to proper management (3). localized leishmania lymphadenitis (lll) is a distinct entity in clinicopathologic field presenting with isolated lymphadenitis and possible cocomitant cutaneous lesion i...

the purpose of this study is to survey cross section changes of the animal brain samples during the tension and compression tests and comparison of the experimental results for three animals: bovine, sheep, and rabbit. a linear elastic theory with considering the necking in tension and barreling in compression has been considered for brain tissue. bridgman method for tension and cross section u...

The dynamic necking instability of a rod of a non-linear viscoplastic material as formed in shaped charges is investigated. A two-dimensional linear Lagrangian perturbation method leads to a single fourth order partial differential equation with time-dependent coefficients. The growth of disturbancies depends of the interplay between the stabilizing inertial and viscous effects, and the destabi...

The purpose of this study is to survey cross section changes of the animal brain samples during the tension and compression tests and comparison of the experimental results for three animals: bovine, sheep, and rabbit. A linear elastic theory with considering the necking in tension and barreling in compression has been considered for brain tissue. Bridgman method for tension and cross section u...