Osypova T. Justification of the effectiveness of the use of damping devices in drum lifting installations during transients

The thesis is devoted to the solution of the actual scientific and practical problem, which is to reduce the maximum dynamic loads in the ropes of drum lifting installations during transient processes, because the steel rope is an integral part of any lifting mechanism, as well as bearing, most responsible and subject to wear element of lift installation. In the process, the steel ropes are stretched and bent, they are exposed to frequent oscillatory loads, which causes the fatigue of the wire material and is one of the causes of the destruction of ropes during long-term operation in lifting machines. In the event of defects on any site, replacement of the entire rope is subject to even a predetermined period, which increases the operating costs of the enterprise. In the thesis the influence of shaft and coil pulley on oscillatory processes in ropes of drum lifting installations is considered. Theoretical investigations of dynamics of five-, three- and two-mass systems of a one-end lifting unit have been carried out, calculations of dynamical coefficients and strength ropes have been calculated. The analytical expressions, which describe the dynamics of the three-mass system of the lifting device, are obtained, and it is possible to determine the moments of the forces of elasticity and the coefficients of the dynamism of the rope. The simplified formulas for determining the maximum values of rope dynamic coefficients are given. For the three-mass system of a two-terminal lifting device, an analytical expression of the effect of "energy transfer" at the moment of the forces of elasticity during the movement of final goods in the trunk is obtained. For a one-end lift installation, we obtain a system of differential equations of displacement of discrete masses taking into account the potential energy of ropes. Studies have been done to reduce the dynamics of ropes of drum lifting installations, taking into account the use of damping devices located between the rope and the final load. Equivalent dynamic circuits are constructed and a mathematical description is obtained in the form of ordinary differential equations at moments of elastic forces with constant coefficients taking into account dissipative forces. In order to confirm the theoretical studies and numerical experiment, experimental research was conducted to determine the dynamics of a single-end lift using a damping device with rubber elements. The engineering methods of calculation of a lifting rope with the use of damping devices with rubber and plate elements with consideration of frictional forces in supporting planes are developed.