Analysis of Underwater Free Vibrations of a Composite Propeller Blade

Abstract

The free vibration characteristics of a composite marine propeller blade were studied. MAB and composite materials were used. Composites with symmetric, balanced and unbalanced stacking sequences were analyzed. Rotational effects and added mass were considered using the finite element method. The natural frequency of the blade in water was much lower than in air. The mode shapes of the blade are almost the same in air as in water. The anisotropy of the composites shift the contours of the mode shape. Generally, greater anisotropy corresponds to a lower natural frequency. The rotational effects can be ignored because the marine propeller rotates slowly.