Stress and Vibration Behavior of Composite Marine Propeller

The marine propeller used in the ship is a critical part whose stability and life play an important role in selecting a particular material. Generally, steel has been used for the past several decades, and very widely used alloys are NAB and MAB. This propeller is subjected to dynamic loads like Torque, Thrust, and Centrifugal bending and centrifugal force. Research work mainly focused on the suitability of composite materials tested for marine propeller application. The static structural and free vibration analysis on composite marine proper is carried. The geometry developed for the scaled model is used for the present simulation. An Attempt is made to modify the propeller geometry by combining 4-bladed B-series propellers and 5-bladed 4381 propellers a modified 4381 propeller geometry developed and used in the present work. Propeller size is scaled down to 6 times to reduce the computation time. The torque, thrust force acting on the propeller, and efficiency of the propeller were computed for the actual and scaled propeller by using the open prop MATLAB tool for advanced velocities from 0.4 to 1.1 m/s. The structural and model analysis is carried out on the scaled propeller blade, the composite layup is arrived at using Hypermesh, and analysis is carried out with the Altair-Optistruct solver. The torque and thrust forces obtained from the open water characteristics study using MATLab, were given as input to the structural analysis. Results revealed that metallic propeller has the lowest displacement, whereas CFRP composite propeller has the next lowest displacement, and GFRP composite has the highest displacement. The model analysis was carried out by using Altair-Hypermesh, the first 10 natural frequencies were extracted, the results revealed that CFRP composite has a higher natural frequency than NAB propeller in the first 4 modes. GFRP has far lower natural frequencies when compared to CFRP.