Experimental study on quasi-static indentation damage resistance of composite laminates

The quasi-static indentation (QSI) damage resistance of composite laminates was tested. Ultrasonic C-scan and SEM were conducted on QSI specimens under two given loads and the damage process was analyzed. The damage resistance of composite laminates was discussed through the initial delamination contact force f₁ and the maximal contact force f₂. The repetitive characteristic of f₂ was confirmed by testing two kinds of materials systems. Moreover, the effects of the test conditions (specimens dimension and clamp hole diameter) and materials properties (the size of fiber, resin matrix and plying pattern) on the maximal contact force were studied. The test results indicate that the effect of the specimens dimension and clamp hole diameter on the maximal contact force is neglect-able, materials components properties (fiber characteristic, resin characteristic and plying ways) could influence the maximal contact force and the dent depth d₂ corresponding with f₂ is principally decided by the strength and elongation of the fiber.