In the present work, a study of the separability property, experimental ηpl factor determination, and load normalization AA 6061-T6 aluminum alloy is described. The separability property has been studied using the Sij parameter with Standard ASTM E 1820-96 SE(B) blunt notch specimens with 8 and 24% side grooving.
The deformation property function H, from variable separability property, was written in terms of plastic and total displacement. The ηpl factor was determined using the Sharobeam and Landes methodology with two side grooves and the two H functions. The ηpl factor values obtained with the H function evaluated in terms of the total and plastic displacement differed by less than 1.4%. The values obtained were close to that suggested in ASTM E 1820-96.
In order to estimate crack length from the test record, the unloading and normalization load methodologies were used. Special attention was paid to the point where the domain of definition of the separability property in plastic displacement started and the influence it had on the estimated crack length. The normalization load was described by means of a standard and a modified power law, and calibration curves were obtained for blunt notched and fatigue precracked specimens.
The degree of restraint introduced by different side-grooving ratios had an influence on the resulting J-R curve, and the three methods employed were sensitive to this change. The toughness obtained with the geometry, dimensions, constraints, test conditions, and material used in this work with different estimation methodologies were in relatively good agreement.