Multi-Parameter Optimierung feuerfester Zustellungen unter Anwendung der Finite-Elemente Simulation

Translated title of the contribution: Multi-parameter optimisation of refractory linings applying finite element simulation
  • Maximilian Klopf

Research output: ThesisDoctoral Thesis

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Abstract

In industrial applications, refractory materials are exposed to thermal and thermomechanical stresses under process conditions. Material failure occurs due to different loading types leading to wear. For this reason, refractory linings adapted to the operating conditions are necessary. The aim of this research work is the thermomechanical optimization of a refractory steel ladle lining on the basis of various geometric parameters using the finite element method and multi-parameter optimization methods. A solid understanding of the material behavior of refractory materials is crucial for reliable simulation results. For this purpose, the material properties of a resin-bonded MgO-C material, used as a wear lining in steel ladles, were determined temperature-dependent up to the application temperature. The further development and improvement of test methods, such as the modified shear test, were necessary in order to determine the material properties under reducing conditions. The MgO-C material exhibits significant anisotropy with respect to the pressing direction and material properties that are dependent on the material preparation, green or coked state. Additionally, a comparison of standard and refractory-specific testing methods for determining cohesion and friction angle at room temperature was conducted. Alongside material testing, Finite Element Simulation served as a database for lining optimization. The slag zone lining of a secondary metallurgical steel ladle was implemented as a unit cell model and irreversible material failure was considered using the Norton-Bailey creep and the Drucker-Prager model. To establish simulation datasets for multi-parameter optimization using TOPSIS and GRA, variations of the working lining brick shape, initial expansion allowance and isolation layer thickness were made. In addition to the lining optimization, an analysis of the trends within the input parameters, such as stresses or strains, regarding variation parameters was carried out. Understanding the failure mechanisms, whether time-dependent or time-independent, is crucial for the optimization and design of refractory linings. The effects of the material models vary significantly over different time periods, are strongly influenced by the material properties and can change depending on the refractory material used. The optimization results show specific tendencies regarding the failure mechanisms, whereby the assignment of specific geometric properties of the linings is possible. The ideal lining configurations, taking into account the material properties of the MgO-C material in green state, consist of brick geometries with larger circumferential dimensions and low initial expansion allowance when applying the Norton-Bailey creep model. For the Drucker-Prager model, the combination of a brick geometry with a small circumferential dimension and larger initial expansion allowance results in the most favourable lining configurations. When the material properties of the coked MgO-C material are applied, the results for both material models are identical and similar to the combinations of the green MgO-C material with the Norton-Bailey creep model.
Translated title of the contributionMulti-parameter optimisation of refractory linings applying finite element simulation
Original languageGerman
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Harmuth, Harald, Assessor A (internal)
  • Aneziris, Cristos G., Assessor A (external), External person
  • Antretter, Thomas, Co-Supervisor (internal)
  • Gruber, Dietmar, Supervisor (internal)
DOIs
Publication statusPublished - 2025

Bibliographical note

no embargo

Keywords

  • lining optimization
  • multi-parameter optimization
  • steel ladle
  • slag zone lining
  • MgO-C
  • material testing

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