Vibration Characteristics of Cracked Rotating Beams Using Higher Order Finite Element Technique

The dynamic behavior of rotating beams with an edge crack was investigated using the higher order finite element method in this paper. The explicit expressions of the resultant stiffness and mass matrices for the variable higher order rotating beam elements were presented in closed form. The edge crack was represented by a rotational massless spring and its equivalent stiffness was derived from the fracture mechanics approach. The present technique was used to predict vibration characteristics of a cracked rotating beam. Numerical results show that the proposed method is superior in computational efficiency as well as accuracy to the conventional finite element method. As vibration characteristics, such as change in natural frequencies, are often applied to predict crack location and size, the present method is of practical significance in crack identification in rotating beams.