Vibration of CFRP cantilever beam with damage

The aim of this paper is the analysis of vibration of undamaged and damaged Carbon Fibre Reinforced Polymer (CFRP) beam elements. Experimental free vibration of CFRP cantilever beam elements were investigated by dynamic tests; damage of CFRP specimens were locally due to double notches close to the fixed end with different reduction of section and bending stiffness. Frequency values were extracted by transformed signals in frequency domain using the Fast Fourier Transform (FFT) technique. A comparison was made of the experimentally extracted frequencies at each damage level and in relation to the single positions of the accelerometer. The present paper illustrates the envelope of Frequency Response Functions (FRFs) obtained by the experimental dynamic tests and the changes of natural frequency values correlated to the damage degree of CFRP beam element. Theoretically, the dynamic behavior of damaged CFRP cantilever beam is studied with an appraisal model adopting an elastic hinge as equivalent concentrated damage. Theoretical data is defined and discussed in comparison to the experimental results.