Introduction
Structural inspection and analysis are important tools for promoting the Structural Integrity assets. They can be applied, for example, to check for possible design faults, investigate unforeseen/unknown phenomena and provide technical support for maintenance planning.
To learn more about these methods, take a look at one of Kot Engenharia's success stories. In this article, an overview of the study will be presented, containing information on the sequence of the work carried out, the non-conformities identified and Kot's actions in correcting these deviations.
To review the basic concepts of the Finite Element Method (FEM) and Visual Inspection, check out the articles:
Structural Inspection of Slag Car
Kot carried out an inspection on a slag trolley at a steel mill. The condition of the structures was checked using visual inspection, liquid penetrant and dimensional analysis methods, with the aim of identifying non-conformities and suggesting the necessary measures to adapt the equipment to safe operation.
A visual inspection was carried out to check the general condition of the equipment, looking for points of deformation and warping. The main welded joints were also inspected and possible deformed profiles and plates were assessed, as well as design modifications. In addition, non-destructive tests were carried out to check for possible cracks in the structure and several non-conformities were found. On the chassis, for example, the points shown in Figure 1 stand out.
Figure 1: General view of the chassis, with identification of the points observed [1].
At point 01 there is a weld in which a crack was observed in the transverse direction of the slag carriage's rolling path, illustrated in Figure 2. This crack was observed in the table of the box profile that forms the chassis.
Figure 2: Crack in the transition beam of the chassis [1].
Figure 3 shows the result of the liquid penetrant test, showing the discontinuity on the surface of the weld region.
Figure 3: Evidence of the liquid penetrant test [1].
After analyzing the inspection, it was realized that, as the defects were distributed throughout the main structures, the safe operation of the equipment was compromised. In view of this, Kot carried out a structural analysis of the car in order to identify the points of concern in the structure and assess the possible causes of the problems observed in the field.
Structural Analysis of a Slag Trolley
In addition to the non-conformities identified during the inspection, a finite element model was prepared for simulation, taking into account the design operating condition, the current field condition and the analysis criteria described in the applicable standards. The study covered static analysis, fatigue and buckling of the slag trolley components. The model and simulation results can be seen in Figure 4 to Figure 7.
Figure 4: Finite element model of the slag car [1].
Figure 5: Utilization rates considering different contact regions [1].
Figure 6: Effect of temperature rise on the belt structure for the pot loading condition [1].
Figure 7: Influence of the pot stop load at the end of tilting on the bogie structure - spring working as a solid body [1].
Kot Engenharia identified the points of concern, analyzed the results obtained in its simulations, and developed solutions that included replacing parts of the equipment. In the end, the study enabled the slag carriage to be adapted to achieve a safe operating cycle.
Kot Engenharia has the experience and resources needed to carry out simulations on tank sides and evaluate problems such as those described in this article. Contact our team to find out more about our solutions and how we can help your business!
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References:
[1] Kot Engenharia Collection.
