Basic parameters of the static stability, loads and strength of the vital parts of a bucket wheel excavator’s slewing superstructure

Abstract

Determining a bucket wheel excavator (BWE)'s slewing superstructure weight and its center of gravity (COG) is of extreme importance not only in the design phase, but also after the completion of the erection process and during the operation of the machine. This paper presents a critical comparative analysis of the basic parameters of the static stability of a BWE 1600 superstructure, with the parameters being obtained by both analytical and experimental procedures. The analysis shows that a relatively small difference in superstructure mass, obtained by calculation, leads to a relatively large unfavorable shifting of its COG, necessitating a significant increase in counterweight mass for balancing. A procedure for superstructure 3D model mass correction is presented based on results obtained by weighing after the completion of the erection process. The developed model provides enough accuracy to determine the superstructure's COG in the entire domain of the bucket wheel boom inclination angle, and enables accurate load analysis of the superstructure's vital parts. The importance of this analysis is reinforced by the finding that the procedure prescribed by standard DIN 22261-2 gives results which are not on the side of safety, as shown by an example of strength analysis of a bucket wheel boom stays' end eyes.

Analysis of the Dynamic Response as a Basis for the Efficient Protection of Large Structure Health Using Controllable Frequency-Controlled Drives

“…These models account for the impacting factors that the creators deem important for the analysis, which potentially leaves room for the occurrence of mistakes or oversights of a variable degree of importance. In addition to the precision with which the structural elements and connections are modelled, the results of the numerical modal analysis are also influenced by the level of accuracy with which the masses are distributed across the considered structure, which was the topic of the studies presented in [19,20]. On the other hand, the accuracy of the results obtained by the means of the experimental approach is dominantly affected by the number and placement of the measuring elements [21], which is also a potential source of mistakes if an experimental and operational approach to the modal analysis is used [22].…”

Multi-objective optimization of tooth surface based on minimum of flash temperature and vibration acceleration root mean square

“…The following point worthy to mention was that the research was based on deterministic methods and accounted for the inevitable randomness of process parameter variations of tooth modification amounts. [13][14][15] As far as several typical practical examples are concerned, tooth modification amounts are random variations due to manufacturing and installing errors as well as several objective physical quantities, which may make gear deterministic modification simplification and thus will improve the effectiveness of tooth modifications on gear performances. Some studies had been proved that through modifying addendum and dedendum, teeth meshing performance could be effectively improved, meshing impact being decreased, noise being reduced, and loading capacity being increased because of teeth surface load uniformly distributing.…”