トンネル窯焼成における粘土瓦の「冷め割れ」についての熱光弾性的研究

Abstract

The thermal fracture of roofing tiles during cooling in tunnel kiln was studied by means of the photothermoelastic technique.The models of roofing tiles were made of epoxy resin plates. The isochromatic photographs of the fringe patterns showed the stress concentrations in the parts of notches and nail holes.For the purpose of decrease of stress concentration, some suggestions regarding the shape of notch and the position of nail hole were obtained. So as to avoid the thermal fracture, wide space setting of roofing tiles on the kiln-car is more effective than modification of cooling schedules.The temperature differences causing failure for the monotonous plate were theoretically estimated at from 160° to 170°C.