Vibrations of beams with two overlapping delaminations

Delamination in composite laminates may arise from either imperfect fabrication processes or impact during service. The locations of the delaminations are arbitrary. In this research, an analytical solution to the free vibrations of a beam with two overlapping delaminations is presented. The delaminated beam is analyzed as seven interconnected Euler–Bernoulli beams. The influence of the sizes and the locations of the delaminations on the fundamental frequency and the mode shape of the beam are investigated. Complex vibration behaviors emerge for different sizes and locations of the delaminations. The results based on the present model agree well with the analytical data reported in the literature.