Optimisation of friction-stir welding process using vibro-acoustic signal analysis

Abstract

This paper presents a mathematical model to predict the tensile strength (TS) of friction-stir welded (FSW) AA1050 aluminium alloy joint. This model has been obtained from the optimisation of the parameters of models developed from vibro-acoustic signals produced during the process. The multiple response method was used to obtain the optimisation model. During experimental development, the process parameters selected to be assessed were rotation speed (RS), travel speed, and tool profile (TP). The TS of the welded joint and the root mean square (RMS) value of the vibro-acoustic signal in the frequency range of 3·2–6·4 kHz were analysed as response variables. In order to validate the model, the optimal values of the factors and responses are presented, showing their agreement with the experimental values obtained. This model can be used to develop and optimise the parameters of the automatic control of the FSW process, based on the vibro-acoustic signal generated.

Keywords:

• Friction-stir welding
• Optimisation
• Vibro-acoustic signal
• Signal processing
• Wavelet transform

This paper has been partially supported by the project of the Spanish Government ‘DPI2011-25007. ‘Friction Stir Welding of dissimilar materials. Characterization by acoustic emission techniques and artificial intelligence’.