Issue 43

F. Majid et alii, Frattura ed Integrità Strutturale, 43 (2018) 97-105; DOI: 10.3221/IGF-ESIS.43.07 105 P ur is the ultimate residual pressure. P u is the ultimate pressure corresponding to an undamaged HDPE specimen. P a is the pressure just before the rupture. P 0 is the endurance limit’s corresponding pressure. σ θ is the circumferential stress. R is the radius of the pipe specimen. t is the thickness of the pipe specimen. a is the notch depth D is the damage (D = 0 for neat material, D = 1 for completely damaged material). β (a/t) = (n/N f ) is the life fraction