Quantifying potential benefits of partial infill on natural frequencies of a compressor blade

Additive manufacturing became a game changer in gas turbines especially for smaller engines as it allows for finer details at smaller scales where existing manufacturing technologies were not feasible. However, to utilize the benefits of AM the design principles should be revised. For turbomachinery blades, one of the key advantages is in partial blade infill – unlike solid machined blades, the 3D printed ones can have the same outer shape but have higher natural frequencies to avoid resonances and be significantly lighter. This paper aims to investigate and quantify the potential benefits for uniform infill and simple lattice structures. The results show a potential of 47%, 35% and 22% rise in natural frequencies for the first three vibration modes respectively, and over 50% mass reduction. The resulting infill shapes agree with physical understanding which led to proposed design principles for rapid exploration of the partial infill for blade frequency control.