Experimental and numerical analyses of thermomechanical refractory lining behaviour

Refractory linings are used in order to protect the steel structure in indu strial applications such as coal-fired power plants or steel ladies. These linings are subjected to important thermal loading that can lead to crackin g (due to the difference between the thermal expansion of steel and the the rmal expansion of the refractory). The aim of this study is to build a tool that allows the structural design to be improved so as to decrease the ref ractory cracking. The first approach is developed on a local scale. A speci al furnace allows the reproduction of the thermal conditions in a coal-fire d plant. Acoustic emission is employed to detect when the refractory is cra cking. A finite element analysis, using three-dimensional elements and a sm eared-crack model, is conducted to reproduce the experimental observations. The material behaviour is identified using an inverse method. This local a pproach can be directly used for structural analyses when the geometry of t he lining is sufficiently simple. For instance, the computation of a steel ladle is presented. When the geometry of the Lining is very complex, it is not possible to compute it with this three-dimensional model. In this case, a simplified approach using a two-layered composite shell, the behaviour o f which is equivalent to the three-dimensional behaviour, is briefly descri bed.