ISSN 2319-5347, ISI Impact Factor: 0.763

VOLUME 03 NO. 04 OCTOBER 2014: 

Title:         FEM simulation of the viscous effects of loading rate on Albany sand
Authors:    Abu Hena Muntakim, Mohammed Saiful Alam Siddiquee
Abstract:   In this research, effect of strain rate on the albany sand has been studied by elastic visco-plastic constitutive model within the three component framework. Strain rate effect can be modeled by using any one of the (i) isotach, (ii) tesra (temporary effects of strain rate and acceleration) or viscous evanescent and (iii) p & n (positive and negative viscosity), models of the three component framework. Usually “isotach” is appropriate for clay and soft rock, “tesra” is appropriate for sand and “p & n” is appropriate for sand with less angularity like albany sand. Here in this research triaxial compression (tc) tests results of albany sand at different strain rate has been modeled successfully into a commercially available package called “abaqus”. The p&n model was implemented into a generalized elasto-plastic isotropic strain-hardening non-linear model in C++. The model is then embedded in the finite element computer program abaqus. Abaqus was used for the actual analysis. In order to define p & n model, user subroutine of abaqus “umat” was written in C++ and used. Abaqus is such a robust fem software that allows writing subroutines for describing material behavior. Generally umat is written in fortran but in this study, the main model is written in C++ and then it is called by fortran with appropriate change in abaqus environment file. Without spending any significant extra computational time or storage this p & n model embedded in fe code can simulate the time-dependent stress-strain behavior accurately.

Keywords:   Constitutive Law, Numerical Simulation ,Three Component Framework, P&N Model, Elasto-Plastic Model, UMAT
Page no:      343-348

Download Full Paper