ИСТИНА

To prevent severe damage in seismically hazardous areas, various sliding joints are added to building structures, for example, slipping attachments. A heavy flat body based on a cylindrical hinge and a homogeneous heavy rod is considered as a model of such a design. The rod slides without friction along a guide rigidly connected to the body, while at one end this rod rests on a rough plane, and at the other end it is connected to the body by means of an elastic spring. The presence of dry friction gives the system the properties of a variable structure problem. The motion of the mechanical system near the vertical equilibrium position is considered. The interaction of an elastic force with dry friction leads to oscillations, which occur qualitatively differently in different regions of the phase plane. The influence of dry friction leads to the formation of an infinite number of damped oscillations performed by the system in an infinite time.