Stress concentration analysis at the blade–strut interface of a Voith schneider propeller using static structural sub-modelling

The blade–strut interface of a Voith Schneider Propeller (VSP) experiences high stress concentrations due to geometric features such as fillets, keyways, and thread reliefs. Conventional global finite element analysis often misses these local stresses, leading to unexpected component failures. This study applied static structural sub-modelling in Ansys Mechanical to analyse stress concentration at this interface. A global model of the VSP assembly was developed with 98,234 solid elements. A detailed sub-model of the blade–strut interface was created with 0.8 mm element size at the fillet. The maximum von Mises stress from the sub-model was 412 MPa, which is 68% higher than the global model prediction of 245 MPa. The stress concentration factor at the blade root fillet was 7.46. Mesh convergence studies confirmed result accuracy. The factor of safety against yielding was 1.7, meeting the required marine standard of 1.5. This study concludes that sub-modelling is necessary for accurate stress analysis at critical VSP interfaces.