Distribution of loads in the large size bearing – problems of identification

Povratni ležajevi velikog promjera koji se koriste u strojevima za površinski kop izrađeni su od nezakaljenih prstena ležaja (raceways). Rezultat toga je jako trošenje izazvano plastičnom deformacijom. Opterećenja koja djeluju na kotrljajuće elemente ležaja ovise o teretu koji se prenosi preko samog ležaja i o krutosti sastavnica stajnog trapa i nadgrađa. Kao posljedica plastičnog trošenja raspodjela opterećenja u ležaju se mijenja. Predmet ispitivanja je bio povratni ležaj pretovarivača LZKS 1600 koji je u upotrebi u radilištu za homogenizaciju ugljena rudnika za površinski kop Belchatow, Poljska. Numeričko i eksperimentalno istraživanje provedeno je sa svrhom određivanja utjecaja krutosti stajnog trapa i nadgrađa na opterećenja kuglica u novom ležaju nakon kratkog vremena uporabe. Uz to, određena je raspodjela opterećenja u odnosu na trošenje zbog plastične deformacije.Large diameter slewing bearings used in open cast machines are made of unhardened raceways. As a consequence the major wear is caused by the plastic deformations. Loads acting on the rolling elements of the bearing depend on the load transferred through the bearing itself and on the superstructure and undercarriage components stiffness. As a consequence of the plastic wear, the load distribution in the bearing is changing. The object of investigations was slewing bearing of the stacker-reclaimer LZKS 1600 which operates on the coal homogenization yard in open cast mine Belchatow, Poland. Numerical and experimental research was carried out with the purpose to determine the influence of the superstructure and undercarriage stiffness on the ball loads in the new bearing after a short operation time. Moreover, the load distribution in terms of plastic wear was determined

Strain gauges measurements and FEM analysis of elements of chassis of open cast mining machines

U članku su prikazani odabrani elementi šasije rudarskih strojeva za površinski kop: upravljački trakt i gusjenice rudarskih strojeva za površinski kop. Opterećenja na svakom elementu su određena u skladu s postojećim normama. Nakon postavljanja graničnih uvjeta, provedena je analiza naprezanja. Rezultati analize su prikazani u tablici. Indikacija najugroženijih mjesta je bazirana na rezultatima analize. Mjerenja tenzometarskom trakom su također provedena na 9 mjernih točaka: 6 točaka na nosačima staze, 2 na potpornjima gusjenice i jedna na uređaju za upravljanje. Mjerenja su obavljena multikanalnim registratorom tijekom pokretanja konvejera. Mjerenja su provedena u različitim položajima karoserije i šasije pod različitim uglovima sklopa za upravljanje. Nakon pregleda rezultata mjerenja dobiveni su podaci koji pokazuju skretanje gusjeničnih sklopova, povećanje i smanjenje snage upravljanja i vučne snage na gusjenici tijekom vožnje i okretanja.In the paper are shown selective elements of chassis of open cast mining machines: control steering track and caterpillar tracks of open cast mining machines. Loads on each element are defined in accordance with current standard requirements norms. After setting boundary conditions, stress analysis was done. Results of analysis are shown in the table. Indication of the most endangered places was based on the results of analysis. Strain gauges measurements were also performed in 9 measuring points: 6 points on track\u27s supports, 2 on caterpillar’s support and one on steering control. The measurements were taken by multichannel recorder during the driving of the conveyor. The measurements were taken for many settings of the body and the chassis with different angles of steering set. After examination of the measurement results some figures were obtained that show turning of caterpillar sets, increasing and decreasing steering force and track force on caterpillar during driving and turning

13th International Conference on Computer Aided Engineering

These proceedings of the 13th International Conference on Computer Aided Engineering present selected papers from the event, which was held in Polanica Zdrój, Poland, from June 22 to 25, 2016. The contributions are organized according to thematic sections on the design and manufacture of machines and technical systems; durability prediction; repairs and retrofitting of power equipment; strength and thermodynamic analyses for power equipment; design and calculation of various types of load-carrying structures; numerical methods for dimensioning materials handling; and long-distance transport equipment. The conference and its proceedings offer a major interdisciplinary forum for researchers and engineers to present the most innovative studies and advances in this dynamic field

Noise Source Identification in Training Facilities and Gyms

This paper deals with noise problems in industrial sites adapted for commercial training venues. The room acoustics of such an object were analyzed in the scope of the reverberation time and potential acoustic adaptation measures are indicated. Identification and classification of noise sources in training facilities and gyms was carried out based on the acoustic measurements. The influence of rubber padding on impact and noise reduction was investigated in the case of chosen noise-intensive exercise activities performed in a previously described acoustic environment. Potential noise reduction measures are proposed in the form of excitation reduction, vibration isolation, and room acoustics adaptation

Adaptation of the machine to the new geological conditions – excavation unit redesign and optimization

The paper presents and sums up the research and technical aspects of the modernization of the cutting tool of the dredger. Improper adjustment of the cutting elements not adjusted to the characteristics of excavated material is not an uncommon situation, causing versatile geological conditions. Relocation of the machines from one pit to another may result in the significant influence on the excavation process (wear, output, etc.). Common practice is the field try and error approach to obtain desired machine performance. In the paper authors present the approach with aid of cutting-edge technologies. Coupled DEM and kinematic simulations supported by the reverse engineering technologies of laser scanning were the fundamental drivers for final adjustments of the cutting tool at its present operational conditions

Numerical and Experimental Investigations of the Influence of Operation on the Technical Condition of Pressure Vessels

The paper presents the issues related to the design and assessment of the technical condition as well as determination of the residual durability of pressure equipment. Based on a real a example, a liquid nitrogen spherical tank, we present the development and applicability of the method for assessment of the durability of the structure. In terms of the material itself, the authors analyze macroscale (structural) factors of the geometry of the real structure (by 3D scanning: material wear detection, deflections and deformations, etc.) and measured real operational loads to develop an integrated method, including material model and behavior in its operational condition, delivering a useful tool for macroscale structural analyses of the materials under complex load (mechanical, thermal, chemical, etc.). As a result, a detailed analysis of the tank is presented. The paper gives an idea of the method, its development, usefulness, and applicability of the presented approach by indication of the mutual influence of pressure vessel components (e.g., stubs, manholes) and operational loads, which may result in underestimating the strength and durability of the pressure vessels in the design process and during operation

Surface mining machines: problems of maintenance and modernization

This unique volume imparts practical information on the operation, maintenance, and modernization of heavy performance machines such as lignite mine machines, bucket wheel excavators, and spreaders. Problems of large scale machines (mega machines) are highly specific and not well recognized in the common mechanical engineering environment. Prof. Rusiński and his co-authors identify solutions that increase the durability of these machines as well as discuss methods of failure analysis and technical condition assessment procedures. "Surface Mining Machines: Problems in Maintenance and Modernization" stands as a much-needed guidebook for engineers facing the particular challenges of heavy performance machines and offers a distinct and interesting demonstration of scale-up issues for researchers and scientists from across the fields of machine design and mechanical engineering

Challenges in the design of a new centrifugal fan with variable impeller geometry

This article presents a description of design work for newly created centrifugal fans. This was done based on the example of an innovative solution that uses a change in impeller geometry. In the described solution, this is achieved by shortening and lengthening the impeller blades. The development of a technical solution with such properties requires a change of approach in the design process compared with classic solutions. Therefore, the following text describes this process from the concept stage to demonstrator tests. The principle of operation of such a solution is presented and the assumptions made based on analytical calculations are also described. The text also shows a 3D model of the centrifugal fan with variable impeller geometry, made with the help of computer aided design (CAD) tools. In the further part, numerical calculations were made on its basis. The finite element method (FEM) calculation made it possible to verify the structural strength of the project and its modal properties as well as to verify flow parameters, thanks to the use of computational fluid dynamics (CFD) calculations. The next step describes the procedure for testing centrifugal fans with variable rotor geometry, which is different from that of fans without this feature. The next part presents the results of research from the tests carried out