4. Quality of physical input data

All models produce results whose accuracy is, at best, that of the input data. Of these, the geometric dimensions (of both tools and blanks) can most often be assumed to be precisely known. The limiting factor is generally considered to be physical data of all kinds.

• Rheological data

  The actual behavior of a metal is always more complicated than you might think. Its anisotropy is rarely taken into account, and is often very real during hot rolling and obvious during cold rolling. We know that deformation fractionation and speed jumps can have an impact – that is rarely taken into account. Little attention has been paid to the fact that metal undergoes combinations of elongation and shear, in varying proportions between core and skin. Low-amplitude cyclic deformations have their own law. We are therefore always led...