CALCULATION OF STRESS-STRAIN CURVES BY USING 2-DIMENSIONAL DISLOCATION DYNAMICS

A method is presented to derive stress-strain curves by using 2 dimens ional dislocation dynamics. The simulation treats plastic deformation of single, grains, in which one or more slip systems are active. The i nvolved dislocations are regarded as infinite straight line defects wh ich are embedded in an otherwise isotropic linear elastic medium. As t he model is two dimensional only edge dislocations are incorporated, T he calculation of the local stressfield considers the long range elast ic stress contribution of ail dislocations within the grain, of the ex ternally imposed stressfields and of the short range stressfield impos ed by large angle grain boundaries. Due to the net local value of the stressfield the dislocations may either glide or climb, Dislocation mu ltiplication, annihilation and reactions are taken into account. Therm al activation is considered, The simulations allow to compute the evol ution of the dislocation distribution, the stressfield and the plastic strain during a simulated deformation experiment. The latter quantiti es are used for the calculation of stress-strain curves.