Non-Destructive Testing Evaluation of Low Velocity Impact Damage in Carbon Fiber-Reinforced Laminated Composites

M. A. PÉREZ; L. GIL; S. OLLER

Workshop; Online Workshop: NDT&E of Composite Materials - CompNDT 2011; 2011

Fiber-reinforced laminated composite materials are widely used in aircraft, modernvehicles and light-weight structures. With their high elastic modulus, highstrength, and capability of being tailored for a several applications, thesematerials offer definite advantages compared to more traditional structuralmaterials. However, their behaviour under impact is of concern since those eventsmay occur during manufacturing, normal operation or maintenance. The situation iscritical for impacts that induce significant internal damage undetectable by visualinspection, which causes large reductions on the strength and stability of thestructure. New standardized tests to assess the impact tolerance (ASTM D7136 andD7137) lose some of its appeal by its destructive nature as well as costs involved.Non-destructive techniques such as ultrasonic phased array or experimental modalanalysis can be complementary in the evaluation of damage and structural integrity.In this paper, the results of both destructive and non-destructive experimentscarried out on 48 composite specimens are presented. A good correlation betweenincident impact energy and delaminated area as well as variation of eigenfrequenciesis noticed. This study does not only provide a better understanding of the impactphenomenon but can also help in design and implementation of new test procedures forstructural assessment.