A viscoplastic model for lava is presented, and its use corium spreading argued with dimensionless numbers. It describes the tridimensional flow as non-Newtonian non-isothermal. Using an adaptive finite element method based on C++ library Rheolef, simulations are ran compared to VEU7 test. sensitivity analysis parameters of that not well-known conducted. Tridimensional solution problem computed...

We consider numerical approximations of a class of abstract nonlinear evolutionary systems arising in the study of quasistatic frictional contact problems for elastic-viscoplastic materials. Both spatially semi-discrete and fully discrete schemes are analyzed with the nite element method employed to discretize the spatial domain. Strong convergence of both approximations is established under mi...

We consider a class of abstract nonlinear evolution systems arising in the study of quasistatic frictionless contact problems for elastic-viscoplastic materials. The variational analysis of such systems, including existence and uniqueness results as well as some properties concerning the behavior of the solution, has been done in 12]. In this paper we consider numerical approximations of this c...

The algorithmic consistency conditions are derived which yield the plastic loading index for the combined isotropic– kinematic hardening plasticity with the Armstrong–Frederick evolution equation for the back stress. Rate-independent elastic–plastic, and rate-dependent viscoelastic–plastic and elastic–viscoplastic material models are all encompassed by the analysis. The directions of the plasti...

Simulations of viscoplastic materials are traditionally governed by continuum mechanics. The viscous behavior is typically modeled as an internal force, defined by diverse quantities. This work introduces a fluid model to simulate the viscoplastic effect of solid materials, such as plastic, wax, clay and polymer. Our method consists in modeling a solid object through a non-Newtonian fluid with ...

We propose and study a new numerical scheme to compute the isothermal and unsteady flow of an incompressible viscoplastic Bingham medium. The main difficulty, for both theoretical and numerical approaches, is due to the non-differentiability of the plastic part of stress tensor in regions where the rate-of-strain tensor vanishes. This is handled by reformulating the definition of the plastic st...

Seth’s transition theory is applied to the problems of thickness variation parameter in a thin rotating disc by finite deformation. Neither the yield criterion nor the associated flow rule is assumed here. The results obtained here are applicable to compressible materials. If the additional condition of incompressibility is imposed, then the expression for stresses corresponds to those arising ...

Spirometry flow-volume loop measurement is the screening test of choice to rule out obstructive lung diseases. Flow oscillations occasionally seen on flow volume loops, referred to as a "saw-tooth" sign, are thought to be due to an upper airway obstructive processes associated with upper airway collapsibility. Widely described in obstructive sleep apnea syndrome, flow oscillations have also bee...