A study for eta sub pl factor determination in AA 6061T6 alloy

The variable separability property has been studied with aluminum alloy AA 6061T6 using three point bending specimens with the methodology proposed by Sharobeam and Landes. In order to obtain the geometry function G(a/W) to calculate eta sub pl factor, the variable separability property was analyzed through the separability parameter S sub ij . Using in one case the deformation function H with plastic displacement and in the other case the same function with total displacement. Records corresponding to the samples with the shortest, medium and the longest crack lengths were taken as reference. For each one of the two options of displacement and the three reference records, the separability was apparent from the S sub ij constancy. As it has been proposed by Sharobeam and Landes for the deformation function with plastic displacement, the S sub ij (b sub i /W) constancy observed here with total displacemnt shows its independency from H( delta /W) under the conditions prevailing in the present work. The eta sub pl obtained in this work using the deformation function H with plastic or total displacement shows no significant difference between them. This behavior could be observed for the shortest, medium and the longest crack lengths. In all cases eta sub pl values obtained were close to those recommended by ASTM E813-87.