DISCRETE-TO-CONTINUUM MODELS IN ANALYSIS AND OPTIMIZATION (MINIMIZATION) OF DYNAMIC LOADS IN ELASTIC ELEMENTS/CARRIER CABLES OF HOISTING MACHINERY USED IN URBAN PLANNING AND TRANSPORT TECHNOLIGIES (Part III)

Abstract

The analysis dynamic loads in elastic elements (ropes) of hoisting mashines and cranes used in urban planning, loading and unloading operations and transport technologies was carried out. Discrete, continuous and discrete-continuous models of crane lifting mechanisms considered. In these models the elastic elements (ropes) are initially considered as elements that have elastic properties of the system with concentrated parameters. Therefore the rope in the lifting mechanism is taken into account as a certain rigidity spring. However, this approach is not correct for quite long ropes (more than 10 meters), in which wave processes can occur during lifting/lowering of loads. These processes can significally increase the dynamic loads − the so-called rope model as a system with distributed parameters. According to the authors of this work, the most correct approach is one that takes into account the discrete properties of the rope (more than 10 meters) itself. That is, the analysis of dynamic loads is carried out within a discrete-continuous model.
 The work consists of several parts, in each of which the dynamic loads in the ropes within each of above starting/braking of the crane lifting mechanisms models are comprehensively and in detail considered. Also parameters of work processes at which the above loads become optimal in magnitude calculated (that is, take the minimum values for different ways of lifting cargo: a)“from the base” (“from the ground”), b)“from the weith”, as, incidentally, the coefficient of dynamism.