Micro-structural analysis of coke using the overlaying mesh finite elementmethod

In order to clarify the bulk breakage mechanism of metallurgical coke in bl ast furnace, the overlaying mesh finite element analysis that can consider both macro and micro-structure simultaneously is applied for complex micro- structural geometry such as coke. We introduced the stress intensity factor , a criterion of stress concentration around the crack tip, which can get f rom displacements of singular points by the template mesh putting on the cr ack tip and evaluated characteristics of fracture for high-strength coke. The numerical results show that the stress intensity factor (K-l*) is depen dent on porosity (epsilon) linearly and then we proposed the following equa tion considering a shape parameter (C) and the stress intensity factor (B) at epsilon =0. K-l*=B(1-C epsilon) This equation shows that the stress intensity factor decreases with porosit y because principal stress around pores in the neighborhood of the crack ti p becomes larger and pores prevent stress around the crack tip from concent rating. This negative effect of relaxation becomes larger as porosity incre ases. Here the parameter C is a specific value, it depends on pore shape an d does not depend on crack length. We conclude that this numerical analysis is very useful for estimation of c oke quality.