Vibration and damping analysis of pre-twisted composite blades

Vibration characteristics of pre-twisted composite blades are analysed using a three-noded triangular cylindrical shell element. The specific example of glass fibre reinforced plastic material is analysed with its material damping. The effect of different parameters such as pre-twist, fibre orientation, skew angle, taper ratio and aspect ratio on natural frequency and system loss factor is investigated. It is found that the maximum fundamental frequency and maximum fundamental loss factor occur at different twist angles and at different fibre orientations. The influence of taper ratio and aspect ratio on 0° and 90° fibre orientations is reported. The effect of skew angle on natural frequency and on system loss factors is seen to be low. © 1993.