Processes taking place in the contact of two bodies and having an influence on strength and service life of machinery or of the whole structure have been in the interest of physicists and engineers for a very long time. The first scientific base had been created by H. Hertz (see Hertz. H.: tJber die Beruhrung. fester elastischer Korper. J. reine und angewandte Mathematik. 1882. 92. pp. 156-171 ) more than one hundred years ago. Since that time (proportionally to the need of industry) countless numbers of other studies have originated, But practice always has been an inspiration for the solution being more general and profound. At the beginning only the problem of the contact of two solid elastic bodies was solved. It was followed with the problems of local load by forces on an elastic half-plane and half-space (see Boussinesq. J.: Application des potentials. d l 'etude de l 'equiZibre et du mouvement des solides elastiques. Paris 1885). The integration then has enlarged the point contact into a surface one so as to correspond to geometry, rigidi ty or physical properties of material in the place of contact.
At present days even the effect of different frictions, origin and propagation of cracks are being solved. Not only mathematics and computers but even modern experimental methods are involved in the solution of problems.