Modal analysis of butt-welded aluminum alloy beams with different welding root widths

In this study, the effect of different welding root widths on the vibrational behavior of butt-welded aluminum alloy structures was investigated using numerical methods. Specimens with dimensions of 250 mm × 25 mm × 5 mm and free-free boundary conditions were modeled in ANSYS Workbench® finite element software, including a weld-free reference specimen and specimens with V-shaped joints at a 60° angle having welding root widths of 0, 1, 2, 3, and 4 mm. Natural frequencies and mode shapes were determined and the first three natural frequencies of the unwelded specimen were calculated based on the Euler-Bernoulli beam theory for comparison. A good agreement was observed between the two methods. The results indicated that geometric variations in the welding region affect the mass-volume values and structural stiffness. In specimens with 0 mm root width, frequency values decreased, while an increasing trend in the first and third natural frequencies was observed for root widths between 1-4 mm. A maximum change of 1.34% was found between the 4 mm welding root specimen and the reference. The second natural frequency remained unchanged, as the welded region corresponded to the node location of the second mode shape. This study is novel in that it investigates the effect of different root widths on vibration behavior. In the future, theoretical, numerical, and experimental studies will be conducted using different material and welding parameters.