Thixotropic materials are complex fluids that display time-dependent viscosity and/or yield-stress response upon the application of a fixed deformation, while recovering their original structured-state when deformation is discontinued. effects presents in many different systems and applications, ranging from food products, such as ketchup, to metals, molten aluminum. In this work we present fir...

In this paper a rate dependent model for unsaturated geomaterials is presented. The formulation and numerical predictions are compared with available experimental results and discussed. The constitutive laws for the description of the time-dependent mechanical behaviour of saturated and unsaturated geomaterials generalize the isotach approach to the elastoplastic strain hardening based constitu...

The spreading under surface tension and gravity of a droplet yield-stress fluid over thin film the same material is studied. converges to final equilibrium shape once driving stresses inside fall below yield stress. Scaling laws are presented for radius complemented with an asymptotic analysis shallow droplets. Moreover, numerical simulations using volume-of-fluid method regularized constitutiv...

Motivated by a model that qualitatively captured the response of vertically aligned carbon nanotube (VACNT) pillars in uniaxial compression, we consider the uniaxial tensile response of a class of compressible elastic-viscoplastic solids. In Hutchens et al. [“Analysis of Uniaxial Compression of Vertically Aligned Carbon Nanotubes,” J. Mech. Phys. Solids, 59, pp. 2227–2237 (2011), Erratum 60, 17...

MARCHAND and Duffy have reported detailed measurements of the temperature and strain as a shear band develops in a HY-100 steel. Assuming their torsional tests in thin-wall tubes can be adequately modeled by a viscoplastic block undergoing overall adiabatic simple shearing deformations. we investigate the effect of modeling the viscoplastic response of the material by a-power law. and flow rule...

A thermomechanical fatigue life prediction model based on the theory of damage mechanics is presented. The damage evolution, corresponding to the material degradation under cyclic thermomechanical loading, is quantified thermodynamic framework. The damage, as an internal state variable, is coupled with unified viscoplastic constitutive model to characterize the response of solder alloys. The da...

Firstand second-order asymptotic solutions are given for the problem of a Mode I crack rapidly propagating in an elastic}viscoplastic solid. Results are obtained for the order of the crack-tip singularity, the angular position at which unloading occurs, and the angular variations of stresses and velocities. It is shown that the eigenvalue, which determines the order of stress singularity, relat...

Ah&act-Steady state thermomechanical deformations of a thick viscoplastic target being penetrated by a fast moving long rigid cylindrical penetrator are analysed by the finite element method. Two different constitutive relations, the Bodner-Partom flow rule, and the Litonski-Batra flow rule, are used to model the viscoplastic response of the material. The two flow rules are calibrated to give e...

*Correspondence: Davide Tiranti, Hydrology and Natural Hazards, Department of Forecasting Systems, Regional Agency for Environmental Protection of Piemonte, Via Pio VII n. 9, 10135 Turin, Italy e-mail: davide.tiranti@ arpa.piemonte.it A method to predict the most probable flow rheology in Alpine debris flows is presented. The methods classifies outcropping rock masses in catchments on the basis...