Original scientific paper The paper presents the issues with the dynamic analysis of mine elevators used with underground exploitation of raw materials. Dynamic occurrences are particularly emphasized with those elevators due to the fact that they are facilities with extreme heights (up to 2000 m) and lifting speeds (up to 20 m/s) using the steel ropes. It shows the forming path of a competent dynamic model for the analysis of such elevators. Basic parameters (stiffness and damping) are of variable magnitude during the lifting, so their values are defined through a combination of theoretical analysis and performed experiments at RTB mine elevators at the town of Bor (Serbia).
Keywords: damping; dynamic model; experimental analysis; mine elevators; stiffness
Teorijsko-eksperimentalna analiza dinamičkih karakteristika rudničkih liftovaIzvorni znanstveni članak U radu je prezentirana problematika dinamičke analize rudničkih liftova koji se koriste pri podzemnoj eksploataciji sirovina. Kod ovih postrojenja posebno su izražene dinamičke pojave, jer se radi o postrojenjima s ekstremnim visinama (do 2000 m) i brzinama dizanja (do 20 m/s) pomoću čeličnih užadi. Prikazan je postupak formiranja mjerodavnog dinamičkog modela za analizu ovakvih postrojenja. Osnovni parametri (krutost i prigušenje) su, u toku dizanja, promjenjive veličine i njihove vrijednosti su određene kombiniranjem teorijske analize i realiziranih eksperimenata na rudničkom liftu u RTB u Boru (Srbija).
Continual material feeding represents a process of great importance for process industries. Feeding with belt feeders represents one of the most common methods. Belt feeders are devices that require little space, they are not expensive and, most importantly, they do not interrupt material flow while feeding. Calibration of belt feeders, as well as other measuring devices, is a prerequisite for measuring and achieving a defined level of measurement accuracy. On the other hand, the defined level of measurement accuracy is often difficult to achieve in practice due to the multitude of factors that affect the operation of belt feeders. Existing mathematical models indicate a number of influential factors on measurement accuracy. The paper presents the measurement procedure performed on a belt feeder in laboratory conditions, with variable speeds and belt tensions and the known raised position of the measuring idler. Based on the obtained results, appropriate conclusions were made about the influences on calibration and measurement accuracy.
U radu je prikazana problematika defnisanja dinamičkih modela liftova i izvoznih postrojenja u rudnicima i metode za rešavanja formiranih matematičkih modela u zavisnosti od osnovnih parametara postrojenja. U eksploataciji se sreću različiti tipovi ovih uređaja od rudničkih i svremenih putničkih liftova sa ekstremnim visinama i brzinama dizanja do klasičnih liftova sa relativno malim vrednostima ovih parametara što uslovljava korišćenje različitih dinamičkih modela i matematičkih metoda za njihovo rešavanje. Pored analize karakteristika i pogodnosti primene pojedinih matematičkih metoda u radu je dat prikaz korišćenja specijalizovanih softvera za dinamičku analizu liftova i izvoznih postrojenja.Ključne reči: Mašine vertikalnog transporta, Mehanički modeli, Analitičke i numeričke metode 0. UVOD IMK-14 -Istraživanje i razvoj u teškoj mašinogradnji
Modelling the dynamic behaviour of elevators with high lifting velocities (contemporary elevators in building construction and mine elevators) is a complex task and an important step in the design process and creating conditions for safe and reliable exploitation of these machines. Due to high heights and lifting velocities, the standard procedures for dynamic exploitation are not adequate. The study presents the method of forming a dynamic model to analyse nonstationary vibrations of a rope with time-varying length with nonholonomic boundary conditions in the position where the rope is connected with the cabin (cage) and in the upcoming point of its winding onto the pulley (drum). A unique method was applied to identify the basic parameters of the dynamic model (stiffness and damping) based on experimental measures for a concrete elevator. Due to the verification of this procedure, the experiment was conducted on a mine elevator in RTB Bor, Serbia. Using the obtained computer-experimental results, the simulations of the dynamic behaviour of an empty and loaded cage were shown. In addition, the study shows the specific method as the basis for forming a control program that would enable the decrease in vertical vibrations during an elevator starting and braking mode.
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