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A unified fracture mechanics test method for quasi-static testing of materials is described. It builds on the ESIS Procedures P1 and P2 and introduces additional aspects, such as the 6, crack tip opening displacement, non-standard CT and SENB specimen configurations, centre cracked tensile specimens, testing of weldments, and guidance for statistical treatment of scattered data. NOMENCLATURE a = actual crack length = starting crack length Aamx = crack extension limit Aa = crack extension b = actual ligament width, W-a B = specimen thickness E = Young's modulus J = J integral . I , = J for stationary crack K = stress intensity factor U = area under force-displacement curve W = specimen width K,= = plane stress fracture toughness U* = area as defined in Fig. 1 = crack tip opening displacement measured explicitly near the tip of the fatigue pre-crackSubscriptsfor fracture parameters S5 and J c = unstable fracture with prior crack extension excluding blunting less than 0.2 mm g = upper limit of 6, or J controlled crack extension i =fracture resistance at initiation of stable crack extension u = unstable fracture with prior crack extension excluding blunting exceeding 0.2 mm uc = unstable fracture with unknown amount of prior stable crack extension 0.2 = fracture resistance at 0.2 mm of total stable crack extension 0.2/BL = fracture resistance at 0.2 mm of stable crack extension excluding blunting

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The EGF Working Party on Fracture Mechanics Testing Standards has written a draft ECF Procedure for determining the crack growth fracture resistance of ductile materials. either in terms of the J-integral or the crack tip opening displacement. Methods are also given for deriving J and 6 fracture parameters related'to initiation of crack growth. The multiple specimen method is taken as the reference method. Several single specimen techniques are described in Appendices. The EGF Procedure is currently being validated by an experimental round robin. F F t M S 116-A N O M E N C L A T U R Eu =crack length a, = fatigue pre-crack length Au = average crack growth Aul = reduced limit for J-controlled crack growth Aag =crack growth due to blunting Aumx = validity limit for J or 6-controlled crack growth Auszw = critical stretch zone width of a specimen zSlw = critical stretch zone width of a material, average of at least three specimens B = specimen thickness B, = net thickness of sidegrooved specimens E = Young's modulus P = applied force J = J-integral. fracture resistance allowing for crack growth Jo = J-integral. fracture resistance not allowing for crack growth J p = J-fracture resistance at upper limit of J-controlled crack growth J, = J-fracture resistance at initiation of crack growth JmaX = validity limit for J J o z = J-fracture resistance at 0.2 mm of total crack growth Jo,z,eL = J-fracture resistance at 0.2 mm crack growth beyond initiation K = stress intensity factor W = specimen width = plastic component of mouth opening displacement 6 = crack tip opening displacement (CTOD), fracture resistance 6, = CTOD, fracture resistance not allowing for crack growth 6, = 6-fracture resistance at upper limit of 6-controlled crack growth 6, = 6-fracture resistance at initiation of crack growth allowing for crack growth 6 , = validity limit for 6 6,' = 6-fracture resistance at 0.2 mm of total crack growth 60.?!8L = 6-fracture resistance at 0.2 mm crack growth beyond initiation a, = reference stress for power law hardening materials ul = flow stress (by + uJ/2 nu = ultimate tensile strength uy = yield strength, 0.2% proof stress w = non-dimensional slope of J-ALI curve 409 410 K.-H. SCHWALBE et ul.

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