Ultrasonic imaging of bubble motion in a fiber preform

Naim Samet , Pierre Marechal (1) , Hugues Duflo (1)

1 LOMC - Laboratoire Ondes et Milieux Complexes

During the Resin Transfer Molding (RTM) process, bubbles can appear and move between fiber strands and fiber folds. In this study, a monitoring method for the size and velocity of air bubbles using an ultrasonic phased array transducer is proposed. This method is tested in a flow of known viscous silicone oil along a sample of fiber preform. By ultrasonic imaging the fiber preform immersed in a viscous flow, a position-time map (xfl, t) is obtained for each acquisition date tacq. These data could be converted to (xfl, z, tacq) data. The bubble motion is extracted from the raw data by separation of the static component from the dynamic part of the signal. As a result, a modified C-scan is obtained and both the instantaneous position and velocity of a bubble could be extracted in the (x, z) plane. Through these measures, the evolution of the bubbles is related to the processes that generate them in order to consider improvements to the RTM technique.

Domaines: Acoustique [physics.class-ph]

Naim Samet, Pierre Marechal, Hugues Duflo. Ultrasonic imaging of bubble motion in a fiber preform. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810855⟩