Internal Geometry Effects on Inherent Damping Performance of Additively Manufactured Components

A recently developed vibration suppressing design approach that leverages the laser powder bed fusion (LPBF) additive manufacturing process is under investigation for damping performance improvement. To date, this approach has demonstrated the ability to design inherent damping capability in LPBF parts that can suppress vibration by 88–95% compared to fully fused counterparts, and the damping capability is a product of only 1–4% unfused powder volume. Despite the documented proof that inherent damping with LPBF can be successful, there are a number of additional demonstrations required to improve the applicability of the approach for turbine engines. Of specific interest in this study is the damping performance sustainability at high strains. This study investigates LPBF nickel-based alloy 718 beams with six different internal geometries and assesses the effects of internal features on damping performance and sustainability. First, the initial/inherent damping performances are compared against undamped results; second, damping sustainability is conducted by subjecting the parts to high strain amplitude loading. Results from this study show a trend in the effects of unfused powder volume on inherent damping performance. In addition, subtle changes in damping performance at higher strains indicate that there are specific internal features more preferable for sustainability of inherent damping.