A Simplified Estimation Method of Blade Stress of Controllable Pitch Propeller

Abstract

It has become usual that the blade strength of a screw propeller running in the wake of ship hull is evaluated by taking into consideration of not only static blade stress but also the dynamic one. Recently Sasajima proposed a simplified method for estimating the dynamic blade stress. In this method, the distribution of the circulation the radial direction is represented by an apriori pattern. Therefore the method isn't able to be applied to the case of controllable pitch propeller of which circulation distribution varies with the blade angle. This paper proposes a modification of the simplified method by use of the blade element model in order to make it applicable to the case of the controllable pitch propeller, and investigates the validity of the proposed method by comparing with the measurement results of an actual controllable pitch propeller.