Editorial

With issue 9 of the 100th volume of the Zeitschrift für Angewandte Mathematik und Mechanik we continue the publication of special papers devoted to the anniversary. The paper Ludwig Föppl and Gerhard Schubert: Unknown Classics of Contact Mechanics written by E. Popova and V. L. Popov highlights an outstanding but mostly unknown contribution of Ludwig Föppl and Gerhard Schubert to contact mechanics. Both of two main techniques of the powerful method described in this paper go back to Ludwig Föppl. In 1941, L. Föppl published a method of determination of elastic deformations under the action of an arbitrary axisymmetric load. Importantly, the two key equations of this formulation had a form allowing for simple inversion, and thus provided a complete solution of the contact problem for an arbitrary axisymmetric punch. This inversion was made in the dissertation of Schubert under supervision of Prof. Föppl.

Karl Ludwig Föppl [1] was at that time professor of Mechanics at the Technische Hochschule München (now University of Technology Munich). The history of this chair is related to several famous scientists: the first holder was Johann Bauschinger [2], followed by August Otto Föppl [3] - Ludwig Föppl's father. In 1922 Ludwig Föppl was appointed as the third chair holder, followed by Heinz Neuber [4], Horst Lippmann [5] and EwaldWerner (the current chair holder). At present, the chair is renamed: Lehrstuhl für Werkstoffkunde und Werkstoffmechanik (Institute of Materials Science and Mechanics of Materials).

Ludwig Föppl had an intensive relationship with the ZAMM – as a member of the Editorial Board and author of several papers on continuum mechanics, structural mechanics, contact mechanics and photoelasticity. It should be mentioned that within the one hundred years history of ZAMM only once it happened that a member of the editorial board (August Föppl was a board member from the beginning) was substituted by his son (Ludwig Föppl was a member of the board from 1924) Figure 1.

G. Schubert published a shortened version of his above-mentioned dissertation in the “Ingenieur-Archiv” (today Archive of Applied Mechanics). This famous and now well-established journal was founded by R. Grammel in 1929 (first issue December 1929). In contrast to the ZAMM, whose focus lies in the interaction of Mathematics and Mechanics, the “Ingenieur-Archiv” was devoted to the interaction between Mechanics and Mechanical and Civil Engineering. The paper of G. Schubert was published in 1942 and met the same fate as many papers of the ZAMM of that time: due to the political situation in Germany only a few researchers studied publications published by German researches and written in German.

As the paper by Schubert presents the best overview of the methods proposed by Föppl, the paper by E. Popova and V.L Popov is mostly devoted to this paper and also contains its complete translation into English.