The temperature distribution of a paper sheet during fracture toughness testing was successively observed as a series of color images by means of an infrared thermography system with close-up lens. No stress concentration accompanied by plastic deformation occurs within the deep double-edge notched tension specimen except around notch tips. A uniformly and plastically deformed region develops from notch tips at the second half of the testing period and becomes a circular plastically deformed region on the ligament just before final sheet failure, irrespective of beating degree.A stable crack has started to grow from notch tips at latest at the point of maximum load.
|Publication status||Published - May 1997|
|MoE publication type||A1 Journal article-refereed|