Demonstrating Damage Resistance and Low Vibration of Laser Powder Bed Fused Blades

Bladed disks (Blisks) are crucial parts of advanced gas turbine engines, each costing as much as $700k. With new purchase and replacement expenses projected to soar into the billions, the search for more cost-effective solutions has become a pressing need in both the commercial and defense sectors. Additive Manufacturing (AM) is a prospective solution with high potential due to the ability to make parts lighter and more affordable. AM is also a more environmentally friendly manufacturing process than traditional approaches. However, the current challenge with AM is that parts are not reliable enough for critical engine use. Specifically, variations in microstructure, porosity, surface roughness, and residual stress can lead to unpredictable damage phenomena. The research conducted to solve this problem explored the use of the i-DAMP design method to inherently suppress vibration in a fan blade and achieve fatigue damage resistance. This work investigates the fatigue life under the same forcing conditions of as-built surface finish i-DAMP and fully fused Nickel Alloy 718 blades made via the Laser Powder Bed Fused blades AM process. The comparisons between i-DAMP and fully fused blades showed 50% vibration suppression at 2nd bending mode with i-DAMP, and a 10X fatigue life resistance was achieved by the i-DAMP blade. The qualitative significance of the research results is that a fully fused (or traditional) blade can lose fatigue life margin in the case of a foreign object damage (FOD) event; however, an i-DAMP blade can still maintain fatigue life margin in the case of FOD.