Wpływ jednoczesnego niejednorodnego tarcia wewnętrznego i zewnętrznego na stateczność układów niekonserwatywnych

The paper presents the problem of stability of Ziegler's model and of a cantilever beam compressed by non-conservative load. The existence of non-homogeneous internal and externa! damping is taken into consideration. It has been proved that the effect of destabilization substantially depends on the ratio of parameters characterizing the internal and external damping, and on the degree of non-homogeneity of these dampings. The critical force has been expressed in terms of the direction of compressive force, the non-homogeneous damping parameters and their ratio, and of the magnitude of damping. The results are accurate in the case of Ziegler's model and approximate in the case of cantilever beam where the approximate energy method of investigation of the stability problem has been applied. The results obtained prove that the external damping decreases the destabilization effect produced by the internal damping.