Luossavaara-Kiirunavaara AB (LKAB) is an international high technologic mining and mineral group that mines and processes Norrbotten’s unique iron ore for the global steel market. In one of the company’s concentrator plants, one out of many processes is to grind various minerals with ball mills. In this work, a static stress- and fatigue analysis has been performed. This work is done on behalf of LKAB. The motivation of this work is to prevent and schedule failure of the mantel2 due to fatigue. The work is based on a simplified model of the dynamic motion that occurs in a ball mill. The model, with attention to the mantel was simulated numerically using the finite element method (FEM), which resulted in a global stress image. Further, the results were used to estimate the life length of the mantel considering the weld. The result from the fatigue calculations predicts a life length of 25 years for the most critical weld. Comparing the results with the time that the mantel has been in operation, it is shown that the calculated life length cannot easily be compared to the operation time. This can primarily be explained by: Uncertainty about the load case and the impacts from the dynamic motion. The welds on the mantel have been re-welded once during its life. Through comparing the results with the detected3 internal defects of the mantel, it is shown that the internal defects likely belong to fatigue damages.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:ltu-64119 |
| Date | January 2017 |
| Creators | Svanberg, Andreas |
| Publisher | Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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