Effect of intermittent heating on drying-induced strain-stress of molded clay

Parametric analyses of the strain-stress in the drying process are performe d to study the influence of the intermittent drying on the behaviors of dry ing-induced strain-stress and deformation as well as the drying characteris tic. The transient three-dimensional problem of strain-stress and heat and moisture transfer in a slab is solved simultaneously by the finite element method. The dimensionless parameters are introduced to generalize the probl em in the conservation equations of heat and moisture transfer. The intermi ttent drying is modeled by applying periodically smaller and larger Blot nu mbers to the boundary conditions. The maximum tensile and compressive stres ses fluctuate, and fall remarkably during the smaller Blot number period wh en a slab is heated intermittently. The peak stress of the fluctuation exce eds beyond the case in the continuous heating where the overall drying rate is almost equivalent to that in the intermittent heating, but the reductio n of the stresses takes place rapidly in the low heating period.