The problem of transient propagation in a homogeneous linear viscoelastic solid is investigated by means of the wave splitting technique. Two mechanical viscoelastic models are considered in particular, corresponding respectively to a single Maxwell element and to the series of a Maxwell element plus a Kelvin element. Analytical solutions for the split field are evaluated in terms of the wave p...

An instrumented indentation method is developed for generating maps of time-dependent viscoelastic and time-independent plastic properties of polymeric materials. The method is based on a pyramidal indentation model consisting of two quadratic viscoelastic Kelvin-like elements and a quadratic plastic element in series. Closed-form solutions for indentation displacement under constant load and c...

For objective 1: Complete the viscoelastic theory. Key individuals are the PI and a PhD student. Task 1: Use an analytical method to determine the propagation of waves through a floating viscoelastic mat for a wide range of effective viscosity and elasticity parameters. This range should include all possible ice cover types in the MIZ. The outcome of this task is a direct relation between visco...

Needle insertion is a minimally invasive technique in diagnosing and treating tumors. However, to perform a surgery accurately, the tissue should have minimum amount of displacement during needle insertion so that it reaches the target tissue. Therefore, the tissue membrane has to move less to decrease rupturing under the membrane. In this study, the effect of different design parameters on dis...

The influences of several operating factors on the viscosity of the Isfahan refinery waxy crude oil sample are studied through conducting some rheological shear rotational tests. The Taguchi design method is adopted to determine the impact of factors such as shear rate, temperature, cooling rate, wax content, and asphaltene content on the viscosity of the waxy crude oil. The results show that t...

CONTEXT Because of the lack of accurate values for mechanically applied forces in osteopathic manipulative treatment, osteopathic physicians must apply mechanical forces intuitively. However, excessive loading and high velocity maneuvers carry risks for patients. OBJECTIVE To determine the loads required to produce compression, shear, extension, and twist on biceps muscle during manual therap...

INTRODUCTION The aim of this study was to compare the efficacy of ibuprofen, viscoelastic bite wafers, and chewing gum in reducing orthodontic pain. METHODS This randomized clinical trial included 50 girls between the ages of 13 and 18 years classified into 5 groups of 10 each: placebo, ibuprofen (400 mg), chewing gum, soft viscoelastic wafer, and hard viscoelastic wafer. The patients in each...

In real systems, the phenomena, such as pipe-wall viscoelasticity, unsteady friction or fluid structure interaction induce additional damping and dispersion of transient pressure waves than that defined by classical waterhammer. In this paper, unsteady friction models and viscoelastic damping models will be presented and a theoretical formulation of the viscoelastic damping in piping systems wi...

The microscopic structure of a plant cell wall is given by cellulose microfibrils embedded in a cell wall matrix. In this paper we consider a microscopic model for interactions between viscoelastic deformations of a plant cell wall and chemical processes in the cell wall matrix. We consider elastic deformations of the cell wall microfibrils and viscoelastic Kelvin–Voigt type deformations of the...

S U M M A R Y We examine the effects of rheological layering on post-seismic deformation using models of an elastic layer over a viscoelastic layer and a viscoelastic half-space. We extend a general linear viscoelastic theory we have previously proposed to models with two layers over a half-space, although we only consider univiscous Maxwell and biviscous Burgers rheologies. In layered viscoela...