Abstract
The present paper proposes a new monitoring system of stress and damage that employs luminance of EL backlight for transparent and semi-transparent composites like glass/epoxy and Al_2O_3/epoxy. For the transparent composites, damage is easily found by visual inspections. In the cases that the structures are sealed or huge structures, however, the visual inspections are difficult. The present paper adopts a system using change of luminance of transmitted light. When the composite structures are loaded and damaged, the load and damage changes luminance of the transmitted light from the backside. The present study adopts an Electro Luminescent device (EL) as the backlight.. Tension and bending tests are conducted using rectangular specimens, and it is experimentally shown that the method can detect the fatigue damage without loading.
