Changes in the state of ice buildup on a composite plate: ultrasonic monitoring and assessment.

From airplane wings to overhead power lines, through large blades of wind turbines, a buildup of ice can cause problems ranging from low performance to catastrophic failure. Therefore, it is of the utmost importance to control or prevent ice formation, especially on the critical areas of the structures. However, de-icing and anti-icing countermeasures can result energetically expensive and harmful to the environment. In addition, excessive use thereof will reduce the life of an ice protection system (IPS) and introduce fatigue to the controlled structures. Therefore, in order to manage properly the available resources, it is desirable to have an IPS that can both detect ice formation and monitor the ice thickness on critical surfaces. This would allow the IPS to operate when it is necessary. Ultrasonic guided-wave-based techniques have proved to be reliable for ice detection but approaches to assess ice state over time have not been reported yet. The present work investigates the interaction of ultrasonic waves, propagating in a composite plate, with an ice mass changing state, as it melts. The use of a metric is discussed as indicator of ice condition variation.