A numerical and experimental investigation on buckling behavior of additively manufactured ribbed casings

Abstract

Laser Beam Powder Bed Fusion (LB-PBF) is a thermomechanical process and residual effects that occur during the process may affect the geometrical stability. Buckling is a type of failure mode for materials, that leads thin materials to buckle under compressive loads. For a more stable buckling behavior in gas turbine engine casings, ribbing structures are being used due to their high compression strength-to-weight ratio. With the advantages of LB-PBF process such as the ability to create complex ribs and reducing machining needs, it can be preferred to manufacture ribbed engine casings via LB-PBF method. In this study, different ribbed engine casings with identical volumes are designed and residual effects caused by LB-PBF are inspected. Buckling simulations are performed on the designed and process simulation-derived casings including the residual strains and stresses, and compressive tests are physically carried out on manufactured parts to compare with simulation results. Following the results of experiments and simulations, residual effects of additive manufacturing distortions over stability were found to be fundamental. It was found that isogrid ribbing yields better resistance towards buckling loads, hinting that lateral ribs contribute more to the overall stability of casings rather than horizontal ribs.