Durability of Crane Metal Structures

Abstract

Abstract. Concentration of loads in structural elements, as well as in machine parts, is created by geometrical concentrators, i.e. local changes in the size and shape of the form from the overturning along the stress line (laps,stiffeners, welded and bolted connections). Concentration of loads is one of the main factors of decrease of support of stiffness of both machine parts and structural elements. The load increase in the concentrator area can be characterized by the theoretical concentration coefficient, but there is no clear methodology for its determination. The operating load ofstructural elements is always non-stationary, and all normative characteristics are set for stationary loads. That is why one of the problems of forecasting the support of the second frame is the estimation of the shock absorption at the rotor, which occurs at the non-stationary process of the load and its replacement by the stationary equivalent in its shock absorption. In a thin-walled girder, the non-planar chord loses its cylindrical shape when loaded. The areas of the belt between the walls try to straighten the angles and increase the radius of curvature under tension, while under compression, on the contrary, their curvature decreases. This leads to a decrease in the longitudinal stiffness of the belt and redistribution of stresses. The article examines the factors that affect the operation of the crane girders of the overhead crane.