Effect of Initial Notch-tip Damage on Failure Behavior of Composite Laminates .

Abstract

Tensile static tests of carbon fiber reinforced composite laminates (CFRP) with a machined notch and an impact notch penetrated by a foreign object were conducted and non-destructive and destructive inspections of the damaged specimens were done to understand the failure mechanism and the effect of initial damage on the damage accumulation process and final failure behavior. The tensile tests of several damaged specimens were suspended several times until final failure to observe the internal damages by using X-ray CT scan machine. A specimens was cut and polished to observe the internal damage state. With the present careful observation, interesting behaviors of the damage growth were found, such as the strong effect of the matrix cracks in the ±45° layers on the fiber failure in not only 0° layers but also 90° layers, dependence of damage growth processes on the initial damage condition and dependence of final strength on the damage accumulation process.