An enhanced homogenization approach for masonry structures with compressible joints. Application to hearth thermomechanical computations.
Résumé
In this paper, a new homogenization-based finite element model to compute masonry structures with compressible joints is proposed. It is an extension of the model proposed by De Felice et al. (Int. J. Numer. Anal. Meth. Geomech. 2010; 34(3):221-247) for dry block structures where strain hardening was neglected. The proposed strain hardening incremental elasto-plastic model is obtained by means of a new step-by-step homogenization method for a running bond masonry structure made of elastic bricks jointed by an elasto-plastic ram. The numerical implicit integration of the model is carried out following an iterative implicit procedure in which the elastic trial stress state is corrected through a return mapping algorithm. The procedure has been implemented in the ABAQUS finite element software and applied to the computation of thermal stresses for the hearths made of small carbon refractory bricks surrounded by very compressible joints. Indeed, during its working, the hearth of the blast furnace is submitted to a high thermal gradient in the radial direction because of the inner heating and the outer cooling imposed to the wall. In our application we evaluate the effect of the joints on the thermal stress distribution within the hearth.