Three-dimensional numerical simulation of the Kalthoff experiment

We use the finite element code DYNA3D to analyze large thermomechanical def ormations of a prenotched plate impacted on the notched side by a cylindric al projectile moving parallel to the axis of the notch. Both the projectile and the plate are assumed to be made of the same thermally softening but s train and strain-rate hardening material. It is found that the maximum spee d imparted to points of the plate on the impact surface equals nearly 90% o f the projectile speed, and the rise time depends upon the quasistatic yiel d stress of the material. Whereas deformations on the midsurface of the pla te closely resemble a plane strain state of deformation, those on the tract ion free front and back surfaces are quite different. Thus measurements mad e on these surfaces may not describe well the deformations occurring in the interior of the plate.