Neki problemi dinamike i čvrstoće mašina visokih performansi

Abstract

Neprekidna eksploatacija u vrlo teškim radnim uslovima dovodi do relativno čestih otkaza podsistema rotornih bagera i pretovarnih mostova za ugalj. Visoko mesto među uzročnicima pomenutih otkaza zauzimaju propusti projektanata - greške u analizi opterećenja, modeliranju i analizi odziva. U radu je izložen originalan postupak identifikacije opterećenja izazvanog otporom kopanja, koji obuhvata sve relevantne konstrukcione parametre, kao i parametre režima rada mašine. Njegova validacija izvršena je merenjima u realnim eksploatacionim uslovima. Osim toga, izložen je i postupak formiranja dinamičkog modela nadgradnje rotornih bagera. On omogućava da se sa dovoljnom tačnošću analizira njen odziv i utvrdi nivo značajnosti parametara pojedinih podsistema. Prezentiran je redizajn obrtne platforme bagera i noseće konstrukcije pretovarnog mosta za ugalj. Rezultati merenja i višegodišnja eksploatacija nedvosmisleno su potvrdili uspešnost primenjenog koncepta redizajna.

Constant exploitation of heavy duty machines, such as the bucket wheel excavator and bridgetype stacker-reclaimer, under the action of highly pronounced dynamic loads, may lead to the failures of their substructures and subassemblies. Unfortunately, high position among the causes of mentioned failures belongs to the designers omissions - mistakes done on the occasion of load analysis, modeling and response analysis. This paper presents an original procedure of calculating external loads caused by force resisting excavation. Model comprises all relevant structural parameters and parameters of duty cycles. Measurements in the real operating conditions have been done in order to establish the credibility of simulation model. Besides that, this paper discusses procedures for dynamic modeling of bucket wheel excavator superstructure. Developed model enables response analysis, with quite satisfactory accuracy, from the engineering point of view. Redesign of the bucket wheel excavator slewing platform, as well as redesign of the bridge-type stacker-reclaimer structure, is presented. The efficiency of these reconstructions is unquestionably confirmed by failure less service of mentioned machines.