Investigation on the correlation between welding parameters and vibro-acoustic characteristics in the stiffened cylindrical shells

As one of the primary joint types, welding processes inevitably induce residual stress, which significantly affects acoustic stealth performance. This research delved into the vibro-acoustic characteristics of stiffened cylindrical shells across various welding parameters, a most typical structure commonly employed in underwater vehicles. Model experiments and computational simulations were conducted to understand how the vibro-acoustic characteristics correlate with different welding parameters, focusing on the impacts of welding energy input, welding speed, and welding sequence. A sensitivity analysis was performed using both experimental and computational data. The comparison of numerical simulation results with model test data showed strong agreement, verified through X-ray diffraction (XRD) measurements. Experimental and numerical studies found that the effects of welding parameters on the vibro-acoustic properties of the structure were significant, which is mainly related to the plate thickness and structural form. For thin flat plate structures, with the rate of change in the first two natural frequencies reaching over 7%. For thickly stiffened cylindrical shell structures, exhibiting a rate of change of around 2%. Moreover, the extent to which welding parameters affect a structure's modal and vibration characteristics is related to its modal mass and mode shape distribution. The vibro-acoustic properties across various frequency bands exhibit a tendency of first reducing and then increasing as the welding energy input increases. Besides, the sensitivity analysis results indicate that the welding energy input exerts the most substantial influence. The research results provide valuable insights for designing acoustic stealth performance in underwater vehicles.