Study on ice impact damage characteristics of turboshaft engine compressor blade considering centrifugal force

When helicopters are operating in extremely cold environments, the centrifugal load generated by the high-speed rotation of the compressor blade will accelerate the impact damage of hail on the blade, damage the blade structure and rotor system dynamics, jeopardizing the operational safety of turboshaft engines, and at present, few studies consider the centrifugal load characteristics of ice impact damage of the compressor blade. This paper derives the Ramberg-Osgood stress-strain equation for the blade material and, by analyzing the effect of centrifugal forces on blade stress, characterizes the intrinsic relationship between centrifugal force and plastic strain. Utilizing implicit/explicit sequential solutions and the finite element-smooth particle hydrodynamics coupling method (FEM-SPH) to establish a dynamic model for ice impact on turboshaft engine blades, taking into account centrifugal force. A custom experimental setup was built to simulate centrifugal force loading on TC4 titanium alloy specimens, followed by ice impact damage experiments under simulated centrifugal force using a high-speed two-stage light gas gun. These experiments served to validate the accuracy of the dynamic modeling method for ice impact damage. The effects of centrifugal force on blade damage characteristics at different impact positions were analyzed. The results indicate that the centrifugal force generated by the high-speed rotation of the blade increases the overall stress experienced by the blade, thereby intensifying the plastic damage caused by the ice impact. Blades taking centrifugal force into account exhibit the greatest damage when ice impact occurs at 83.3 % span, with the effective plastic strain being 166.2 % higher compared to that not considering centrifugal force. The conclusions of this paper provide theoretical references and data support for the strength design and impact protection of turboshaft engine compressor blades.