Identification of Impact Damages in Aircraft Composites by Nonlinear Guided Wave Technique

Abstract

To maintain the best possible structural integrity of composites, it is highly desirable to detect the impact damage at the smallest possible scale. Nonlinear ultrasonic guided waves technique has been accepted as a useful tool for evaluating and detecting the micro-damages in early stage. Considering that second harmonics could provide information sensitive for structural health condition, this paper investigates an experimental scheme for measuring the micro-damages caused by low-velocity impacts in carbon/epoxy composites. The degree of injury is demonstrated with the impact energy. The present results show a monotonic increase of acoustic nonlinearity with respect to the increase of impact energy. This relevance between the acoustic nonlinear parameters and impact energy indicates that the use of nonlinear ultrasonic guided wave can be a sensitive means for the low-velocity impact damages in composites