Effect of impact failure on the damping characteristics of beam-like composite structures

This study deals with the free vibration response and damping characteristic of a cantilever composite beam having a single impact failure on it. The fundamental vibration frequency of the beam is measured experimentally using a non-contact technique for different failure locations and the damping ratio is calculated from the envelope of the free vibration response. A failure model based on the delamination formation is used in the finite element model of the damaged composite beam to determine the fundamental vibration frequencies. In the finite element modeling, ANSYS APDL language is used to create the composite beam model with different failure sizes and locations automatically. Experimental results show that damping ratio is more sensitive to a failure on the beam than the natural frequency and severity and location of the failure have considerable effects on the damping ratio.