Modeling of dynamic loadings on a tower crane jib

Article describe processes of modeling of dynamic loadings on on a tower crane jib and represent their in analytic and, graphic kinds with using of modern computer technologies. Complexity of such tasks is concluded in depending these characteristics from load characteristics of the crane, weights and inertial parameters of elements of the mechanism of the lifting of loads, having a nonlinear appearance. The proposed procedures of modeling allow to reduce time and costs of such calculations at least in several hundred times and effectively to carry out researches in any usage mode and on all design stages of tower cranes, providing good visual presentation of received results.


Introduction
Article describe process of modeling of dynamic loadings on a tower crane jib. It is necessary originally: to simulate the load characteristic of the tower crane in an analytical kind; to define the resulted moments of inertia of rotating bodies and lifted load to an engine rotor; to define time, a way and acceleration of dispersal of load at its lifting, depending on a load site on a jib and representation their in analytic and graphic kinds in MathCad system. [1] [2] The proposed procedures of modeling and calculations allow to reduce time and costs of such calculations at least in several hundred times and effectively to carry out researches in any usage mode and exploitation of transport means, providing good visual presentation of received results. [3] 2 Statement of the problem The load characteristic of the tower crane in a graphic kind is known, as a rule, looks how is shown on fig. 1. In an analytical kind the load characteristic of the tower crane can be presented such expression.
-In the range r1 -r2 Q1-2 (r) = Q2, -In the range r2 -r3 where: Mcr -moment from constructive weight of the crane in working status, kN·m; Mcl -moment from weight of counterload in working status kN·m; Mwcr -moment from wind loading on the crane in working order, kN·m; Mwl -moment from wind loading on load in working order, kN·m; Mimcr -inertia moment at crane dispersal, kN·m; Mimla -inertia moment at load dispersal along, kN·m; Mimlv -inertia moment at load dispersal on a vertical, kN·m; Mcfl -moment from centrifugal force of load, kN·m; Кsscr -factor of a stock of stability of the crane in working status; B -base of the crane, m; α -maximal gradient angle, degree; H5 -height of a heel of an arrow, m.
In an analytical kind can define the resulted moments of inertia of rotating bodies and lifted load to an engine rotor.

Modeling algorithm in system Mathcad
This paragraph shows the program in the MATHCAD system in the form of screenshots of the computer screen. [4][5] This program can be used to calculate and simulate dynamic loads on the jib of a tower crane. In fig. 2,3 shows modelling of load characteristics of the tower crane process.

Conclusion
The proposed procedures of modeling of dynamic loadings on a tower crane jib allow to reduce time and costs of such calculations at least in several hundred times and effectively to carry out researches in any usage mode and all design stages of tower cranes, providing good visual presentation of received results.
The reported study was funded by RFBR according to the research project № 20-38-90168