Optimisation of hardness and tensile strength of friction stir welded AA6061 alloy using response surface methodology coupled with grey relational analysis and principle component analysis

Abstract

The present work aims to optimize the operating parameters such as rotational speed, welding speed and tool diameter for maximum Hardness and Tensile strength of the friction stir welded joint on AA6061 alloy. Three factors with five level response surface design matrix were developed by using MINITAB14 software package. Response Surface Methodology (RSM) was adopted to develop mathematical model between the response and process parameters. Grey relational Analysis (GRA) was deployed to convert multi objective case into single objective one by calculating Grey Relational Grade (GRG). The weights of the influencing parameters were calculated using Principle Component Analysis (PCA). The optimum process parameters are obtained from Response surface plots drawn for GRG. Confirmation tests proved that the proposed methodology has been yielded the optimum process parameters.

Keywords: Friction Stir Welding; Response Surface Method; Grey Relational Analysis; Grey Relational Grade; Principle Component Analysis