Browsing by Subject "state of stress"

Now showing 1 - 6 of 6

Access status: Open Access ,
Analiza rozkładu wstrząsów górotworu w rejonie ściany B-l pokładu 403/3 w aspekcie wybranych czynników górniczych i geologicznych
(2007) Małkowski, Piotr; Majcherczyk, Tadeusz; Niedbalski, Zbigniew
The paper presents rockbursts layout in the area of the longwall B-1 which was located close to the faults. Recording dynamic phenomenas let assume, that seismic activity in the region were shown by the exploitation and regional tremors. The analysis of the stress field and the failure zone in the longwall B-1 area proved that one group of tremors were connected with mining factors and the second one with rock mass movements on the fault surface.
Access status: Open Access ,
Evaluation of the state of stress in structural components of a screen separator
(2010) Wolny, Stanisław; Banaszewski, Tadeusz; Dzik, Stanisław; Matachowski, Filip
This study summarises the results of FEM analysis of the state of stress generated in structural components of a PZ3R screen separator under the typical operating conditions. Simplifications underlying the numerical analysis were verified by measuring the stresses in selected parts of the machine. Resistance test data indicated the directions for further modifications of structural elements of the screen separator, at the same time confirming the adequacy of these tests and emphasising the importance of the sequence of the applied tests.
Access status: Open Access ,
Modelowanie numeryczne stanu naprężenia w sąsiedztwie przodka wyrobiska ścianowego z uwzględnieniem obecności metanu
(Wydawnictwa AGH, 2011) Florkowska, Lucyna; Walaszczyk, Jan
Knowing the state of stress within rock mass near the exploitation area is a crucial element of planning mining works, especially in areas containing methane, which often happens in case of coal exploitation. One of the solutions to this problem is numerical modeling. This paper presents a method of estimating the changes of the state of stress around long wall exploitation area, based on MES numerical simulation. Mathematical model used here, treating coal as porous compressible medium, considers the presence of methane within rock mass and its flow caused by exploitation. It allows to observe both the changes of the state of stress and of methane porous pressure within rock mass. The results obtained were compared to the results of methane pressure tests available in literature.
Access status: Open Access ,
Statistical evaluation of the measurement of residual stresses in the surface layer of CP1000 steel sheets using the magnetic Barkhausen noise and X-ray methods
(Wydawnictwa AGH, 2025) Kliś, Janusz; Nawrat, Rafał; Olbrych, Jakub; Węgrzyniak, Michał; Szydło, Damian; Toczek, Grzegorz; Sozańska-Jędrasik, Liwia
The paper presents an analysis of the possibility of measuring the residual stresses of metal sheets with the application of the so-called Barkhausen effect. The aim of the research was to compare the residual stress levels measured by two methods of multiphase steel sheets (ferritic-martensitic-bainitic) in grade HCT980C after flattening on a roller leveller in industrial conditions. The measurements were carried out using two methods: the Barkhausen effect method and the X-ray method. The paper describes in detail the methodology used for testing the measurement of residual stresses. The residual stress testing of sheets made of the CP1000 steel group was supplemented with tests of chemical composition, microstructure and mechanical properties (Re, Rm, A80, HRC hardness). In the analysis of the research results, elements of statistics were also used, in the form of ordinary correlation. The research results showed that in the case of sheets after flattening on a roller leveller in industrial conditions, it is possible to replace the commonly used and recognized, but labour-intensive X-ray method, with a simple, innovative and cheap to use method using the Barkhausen effect. Stress measurement using the Barkhausen effect has already been found to be applicable in the diagnostics of tracking changes in the stress value in the material in industrial pipelines, where access to the other measurement methods is difficult or even impossible. Currently, the measurement of stress in sheets by the magnetic method is introduced on the transverse cutting line when cutting the sheet metal from coils to metal sheets. The measurement of stresses in the production of steel sheets is important because the difference in stress between the top and bottom sides of the sheet has a significant effect on the flatness of manufactured metal sheets.
Access status: Open Access ,
Strength analysis of a gantry crane of a coating structure
(2012) Ładecki, Bogusław; Badura, Sławomir; Matachowski, Filip
Gantry cranes with coating construction are used in Polish steel industry much less than truss bridges. For several bridges, which span and the supports have coating construction, there were made series of non-destructive testing, which revealed the presence of numerous fatigue cracks: in the area of a beam pad, the coating, as well as other elements of their supporting structure. Periodically carried out repairs and strengthening of bridges have not eliminated the problem of the emergence of more fatigue cracks. The analysis of FEM, verified by extensometer measurements of strains, gave the basis to designate the most strenuous areas of the construction. Gathered results of periodic non-destructive testing, combined with obtained results of FEM analysis, were the basis for designing appropriate reinforcements and indication the scope of conducting non-destructive testing of considered construction of bridges with coating.
Access status: Open Access ,
Wpływ szerokości filara oporowego dla chodnika przyścianowego na stan naprężenia w jego otoczeniu
(Wydawnictwa AGH, 2011) Majcherczyk, Tadeusz; Niedbalski, Zbigniew; Małkowski, Piotr
The paper presents the analysis of the influence of support pillar width left between a goaf and a gate drifted for the consecutive longwall on the state of stress and strain. The widths of pillar from 4 m to 10 m were analyzed to ensure the gate functionality for the subsequent longwall panel. The case concerns the necessity of defining main gate locations which close the panel for longwalls B-11 and B-11a in the seam 348. The mining and geological conditions on the spot were found as exceptionally hard due to bed inclinations up to 240, methane hazard and goafs on both sides of the longwall panel. The location of the analyzed workings takes into consideration both the economic conditions and the optimal pillar width, which additionally ensure gate stability.