Investigation of dynamic characteristics of carbon composites by laser Doppler vibrometry

Using a laser Doppler vibrometer, a noncontact measurement of the damping factor and vibration velocity of a rectangular, cantilevered carbon composite specimen under conditions of vibration load of varying intensity is carried out. The range of loading rates is 0-255 mm/s. It has been found that, as the loading rate increases to 5 mm/s, the value of the damping factor decreases nonlinearly, and, for larger values, it fluctuates near a certain constant value. With the approach of the scanning point of the sample to the place where it is fixed, the damping factor increases. It is shown that there is a certain distance from the place where the sample is fixed, for which an increase in the intensity of the applied vibrational load causes the smallest increase in the maximum value of vibration velocity.