Abstract: A product comprised of a non-linear piezoelectric materia, in which a plurality of reference points are defined. The product is exposed to a distribution of an electrical field and is characterized by a distribution of characteristic linear moduli over the reference points, whereby each modulus is determined as an increase in a secant reaching, in an associated characteristic curve, from a zero point up to a point corresponding to the reference point. The characteristic curve is projected from a system of characteristic curves that describes relations between the electrical field and loadings characteristic of additional state quantities in the material. In addition, the invention relates to a method for determining a corresponding distribution of characteristic moduli in a corresponding product.