14. starptautiskā konference 2012 - Latvijas Jūras akadēmija

Proceedings of 14th International conference „Maritime Transport and Infrastructure - 2012”In case of "dry" surfaces contact, it is found that the adhesive interaction increases. As shownin Fig. 4, with a decrease of liquid in the meniscus adhesion component in friction bearings increases.Form of protrusive roughness is important during contact, which can be examined usingsimple models (Fig. 5).Fig. 5 The effect of the form of asperity on contact interaction in two areas:1 – flattening; 2 – setting in the function of the angle :h– height of asperity; - angle between asperity slope and friction surface;R – conventional radius of asperityAs seen in Fig. 5 (for example, carbon steel) at 180 о setting is dominated, at 80 о –flattening, and the loads are related as follows:hRTK( E),(12)where Е – modulus of elasticity; T – flowability boundary, К has following values:if max тK = 2,4;if сред тK = 5,4.It should be noted that during friction and contact the state of the material properties of thesurface layer changes due to wear-in. The micro-and macrogeometry of contact, height, shape, pitch ofasperities are changed due to the wear-in and deformation of surfaces. In addition, the structure of thesurface layer of material changes - defects in the crystal structure: the point (vacancies), line(dislocation type) appears; boundaries are developed, coagulation defects of various origins, formationand dissolution of carbides, diffusion, phase transformation (formation of new phases), etc. that leadsto the recrystallization, amorphization and the formation of secondary structures (most often - thefilms of oxides) and adsorbed films.147