Abstract
This study conducts a tensile test of side notched welded joints composed of thick plate to evaluate the fracture ductility. Experimental parameters involved are four kinds : thickness, half notch length, material property and notch location. The COD (δ) and overall strain (ε_∞) were measured as a deformation property. All specimens rupture in full yielding region, at which the increment of COD increases until the linear relationship disappears. The COD of this point is assumed as the critical value of crack propagation δ_c. Critical fracture value uniformly increases as notch length (a) increases and can be expressed linearly for each property of steel. The gradient of δ/2πaε_y-ε_∞/ε_y relation at δ_c and notch length can be expressed with linear form for each steel.
