Branko Ladanyi

A unified viscoplastic model for the inelastic flow of alkali halides

Abstract The present paper proposes a novel viscoplastic model to describe the inelastic behaviour of polycrystalline alkali halides. This model is of the unified type. It consists of a kinetic law and three evolution laws associated with three state variables, B, R and K. Variables B and R are internal stresses, which usually oppose the applied stress, and which induce kinematic and isotropic hardening respectively. The variable K is a scalar used to normalize the active stress, thus contributing to the isotropic hardening of the material. The proposed unified model is physically based, and allows a correct representation of both transient and steady-state flow under diverse loading conditions. It is valid for both instantaneous (plastic) and delayed (creep) components of the inelastic strains. Various phenomenological attributes of the model are discussed and compared to the theoretical and experimental behavior of polycrystalline alkali halides.

Modelling of coupled heat, moisture and stress field in freezing soil

Abstract A model for coupled heat, moisture and stress field in freezing soil is proposed. A numerical simulation for an experiment published by Penner (1986) in saturated soil using this model is carried out. The results of the simulation for temperature field and heave agree well with the experimental results. In addition, the stress field in freezing soil is also given by this model. The model is well adapted for solving practical frost heave problems in which the heave is coupled with deviatoric creep, such as under foundations or around chilled buried pipelines.

An internal variable model for the creep of rocksalt

SummaryThe creep strain rate

Heat Flow in Soils

\dot \varepsilon

FEM simulation of interface problem for laterally loaded piles in permafrost

of rocksalt, like that of other ductile crystalline materials, can be described by a power law equation of the type

Physical and Thermal Properties

\dot \varepsilon