Studies on quasi-static indentation damage and compressive failure of composite laminates

An experimental investigation was performed on the characteristics and damage of composite laminates with quasi-static indenting. The compressive behavior of laminates after quasi-static indentation was studied also in order to examine the validity of one CAI test method with the minimized specimen. Methods of ultrasonic C-scan, were used to measure the damages of the laminates. The CAI strengths of laminates with the quasi-static indentation damage were compared with that of laminates after low velocity impact. The results showed that there were ultimate load and a threshold load or a threshold indentation depth below which no damage occurred while laminates were indented. The distribution of delamination areas along laminate thickness of the CAI test method with the minimized specimen was different from that of SACMA CAI test method. The compressive failure modes of these two methods were different.