Multi Response Optimization of Process Parameters on AA8011 Friction Stir Welded Aluminium Alloys Using RSM Based GRA Coupled with DEA

Abstract

The friction stir welding process is the newly developed material joining process used to join the different materials which are very difficult to join in the conventional fusion welding process. In this investigation using the specially designed straight cam profiled tool, the multiple responses of Ultimate tensile strength, Ultimate yield strength and Percentage of elongation with the process parameters of rotational speed, tool tilt angle and feed rate are optimized. The five level, three factor rotatable central composite design is selected to optimize the responses of friction stir welded AA 8011 aluminium alloys. The highest gray relational grade with the highest relative efficiency is found using the gray relational analysis coupled with the data envelopment analysis to predict the optimum parameters. It exposes that at the rotational speed of 680 rpm, the tool tilt angle of 98 degrees and the feed rate of 24 mm/min the good weld quality can be attained.