Evaluation of Impact Damage in Composite Structures Using Ultrasonic Testing

Barely visible impact damage is one of the problems commonly occurring in composite elements during an aircraft operation. The authors described the mechanisms of impact damage formation and propagation in composite structures. The paper presents a performed analysis of an influence of impact parameters on the resulting damage, i.e. its detectability by means of visual observation as well as its extent determined based on ultrasonic tests results. The tests were conducted on the CFRP specimens with a wide range of impact damage cases obtained with combinations of variable impact energy and shapes of impactors. Additionally, an algorithm based on image processing and image analysis methods is proposed for the purpose of the effective evaluation of the ultrasonic data obtained.