Studying the vibratory behavior of inherently damped laser powder bed fused (LPBF) specimens has led to an improved damping performance assessment via a multi-factor correlation model. The inherent damping demonstrated of LPBF (an Additive Manufacturing process) specimens is an artifact of a 1-3% unfused volume of powder that is capable of suppressing vibration 95% compared to a fully-fused part. The original model associates the damping mechanism to unfused powder motion and a sliding interaction, both respectively captured by the interaction between vibratory shear load and displacement. In previous studies with only a few specimen configurations, this two-variable, one-parameter nonlinear model has demonstrated 85-90% correlation to experimental damping results. However, the complexity of multiple material data sets, different build cycles, and a multitude of internal geometry configurations has reduced this correlation and highlighted a necessity for exploring other factors along with the current factors without interaction. The following effort uses a regression model to study the effects of vibratory factors on the damping performance. The factors and interactions explored for this model are intuitively limited to material type, mode sequence, displacement, shear-displacement interaction, and the percent areas of the respective displacement and shear-displacement interaction curves associated with the unfused powder volume. Empirical data is acquired from Inconel 718 and Stainless Steel 316L specimens. Using a backwards elimination stepwise regression and Akaike's Information Criterion, results show that an additional model parameter along with the original nonlinear correlation model is more accurate for assessing damping performance of unique LPBF components.
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