Characterisation of blade out events using powder bed fusion of polymers

The release of a blade, hereafter referred to as a blade-out event, in an aviation gas turbine engine (GTE) represents a serious safety hazard. Such an event can result in severe dynamic imbalance, engine failure, and potential fire hazards. Full-scale blade-out testing of GTEs is extremely costly, hazardous, and time-consuming. To address these challenges, we developed a novel, instrumented, scaled-down test rig to perform multiple blade-out tests using dynamic similarity principles based on Buckingham’s theorem. In this design, the rotating disk assembly comprises sixteen pre-twisted blades, each 50[Formula: see text]mm in length and attached via dovetail roots. Both the blades and disk are composed of Polyamide 12 and were fabricated using the powder bed fusion of polymers with laser beam (PBF-LB/P), a 3D additive manufacturing technique that employs high-power lasers to fuse fine powder materials into solid structures with complex geometries. The application of PBF-LB/P was crucial for achieving accurate, rapid, and cost-effective manufacturing of the blades, allowing numerous blade-out tests to be performed efficiently. This is particularly significant since blade-out tests typically cause extensive damage not only to the released blade but also to the trailing blades. The use of PBF-LB/P therefore enabled the execution of a large number of blade-out tests, the results of which were compared with finite element (FE) simulations of blade release in real GTEs. The findings demonstrate excellent agreement between the two approaches, confirming that the scaled-down rig can accurately capture the trajectories of released blades and their interactions with trailing blades.