Development and assessment of a propeller shaft load measurement system

Accurate model-scale measurement of dynamic shaft loads remains a significant challenge in characterizing propeller-induced noise and vibration. Conventional test methods lack the ability to directly capture high-frequency, multi-axis forces at the propeller shaft, limiting the fidelity of validation data for predictive models. To address this gap, a novel shafting system has been developed to measure six-component propeller loads directly, facilitating high-frequency shaft vibration characterizations in a model-scale test setup. This isa unique sensory system to capture high-frequency propeller-induced vibration forces directly at the hub. At its core is an AMTI SP1-500load sensor integrated into a custom-designed shaft assembly capable of resolving axial thrust, torque, and lateral loads induced by the propeller. The system was qualified through in-situ testing, with data cross-compared to conventional propeller dynamometry, pressure sensors, and accelerometers. Frequency-domain analysis showed strong alignment of load and vibration signatures at propeller blade harmonics, primarily below 200 Hz. These direct shaft load measurements at the propeller hub provide critical insights into the dynamic forcing mechanisms that contribute to propeller noise and hull-excited vibrations, offering a powerful tool for validating computational fluid dynamics (CFD) models and improving quiet ship design.