Mechanical Properties of Ultrasonically Welded Aluminum Sheets and the Effect of Process Parameters

  • Shamsa Awes

Student thesis: Master's Thesis

Abstract

This study is an experimental and numerical investigation of ultrasonic spot welding process of thin aluminum sheets with the aim of developing a regression model that would evaluate the weld strength by the prediction of the maximum tensile load under lap-shear test. The experimental analysis was conducted according to the full factorial design to test the effect of clamping force, welding time, welding power and their interactions on the tensile strength of the spot welded lap joints. A regression model was developed, based on these experimental data, to link the control parameters with the maximum tensile strength. The developed model predicts that the dominant process parameter that has the greatest influence on the tensile strength is the welding power. Moreover, microscopic images for the nugget structure and micro-hardness tests were performed and analyzed. Results showed that for high power values with sufficient welding time a shift in the failure mode is observed, from interfacial failure to pull-out failure. Finite element modeling was also performed in ANSYS Workbench with the aim of developing a model that can predict the failure load of a spot welded specimen under a lap-shear test by incorporating the experimental measured properties of the nugget and the base metal. The numerical results have been validated against the experimental data.
Date of Award2016
Original languageAmerican English
SupervisorShadi Balawi (Supervisor)

Keywords

  • Ultrasonic spot metal welding; Aluminum sheets; Mechanical properties; Joints strength; Numerical analysis

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