A New Estimation Method of Coke Strength by Numerical Multiscale Analysis

摘要

The homogenization method is proposed as new numerical approach to understand the fracture mechanism of the microscopic behavior in coke because the evaluations of the strength has been still difficult for the improvement of coke qualities in coke making process. The conditions for the stress concentration and relaxation effect are investigated by homogenization method. These results show that the distribution of micro cracks and pores in coke is important factor for the microscopic fracture. Also, the digital image technique is applied to the actual coke with the complicated microstructure and the improvement mechanism of coke strength by the carbon deposition is clarified by using homogenization method. The effect of carbon deposition on the coke strength is illustrated from the stress distribution while calculating the homogenized elastic modulus. Although the stress concentration between large pores is caused in the case of carbon deposited coke, the maximum stress becomes smaller than the tensile strength of coke because of large homogenized elastic modulus. As a result, the microscopic fracture does not easily occur for carbon deposited coke.