ABSTRACT
Figures 1-4 present plane strain results for uniaxial compression and extension using a different characteristic length (Bobinski & Tejchman, 2004). The specimen was b = 4 cm wide and h = 14 cm high. The deformations were initiated through constant vertical displacement increments prescribed to nodes along the upper edge of the specimen. The lower and upper edge were smooth or rough. The standard boundary conditions of the classical continuum theory were used along the specimen’s edges. In FE-analyses, the internal friction angle ϕ was 25◦ and the dilatancy angle ψ was taken as 10◦, the elastic modulus was E = 29.0 GPa, the Poisson’s ratio υ= 0.18, the maximum cohesion yield stressσmaxy = 32 MPa, tensile strength ft = 2 MPa and the constant softening modulus H = 0.8 GPa. The localization was induced by one small material imperfection in the form of a weak element at mid-height of the specimen side.
