VISCOELASTIC ANALYSIS OF NEARLY INCOMPRESSIBLE SOLIDS

Abstract

The finite element method is well established for the analysis of structures and other field problems. However, its straightforward application for the analysis of nearly incompressible solids yields erratic results. In the present work, an efficient special purpose code for the Viscoelastic Analysis of Nearly Incompressible Solids (VANIS) is developed using isoparametric elements with selective integration pro- cedure, which is a third order Gauss rule for deviatoric response and second order Gauss rule for volumetric response. The software can be effectively employed for the structures with lower Poisson’s ratios. VANIS is based on the direct formulation using linear uncoupled thermoviscoelastic theory for the thermorheolog- icaUy simple materials. The element library consists of 8-noded plane strain, I-noded axisymmetric solid and 20-noded three dimensional quadratic isoparametric elements. These elements meet all the possible structural idealisation requirements of the solid continua. Experimentally obtained rigidity modulus can be used directly or expressing it in Prony series. The software is tested on a number of problems and gives very accurate results for all the permissible values of the Poisson’s ratio.