J. Welsch
The University of British Columbia, BC, Canada
Keywords: Non-destructive Testing, Quality Assurance, Composite Manufacturing
With the increasing use of composite structures and their growing complexity, quality assurance during manufacturing has become paramount. One of the most commonly used processes today is Vacuum Assisted Resin Infusion (VARI). In this process, sheets of composite fibers are placed into or over forms, encased in vacuum bags, and then infiltrated with resin that is drawn between the fibers by an existing vacuum. A significant challenge in this process is managing and supervising the flow front of the incoming resin to prevent voids or dry spots, as well as monitoring the curing process to detect or even prevent warping and residual stress. Current commercial solutions, such as capacitive sensors that measure electrical resistance, are expensive and require access to both sides of the part, limiting their application. We propose active polyCMUTs as a solution. These flexible, thin, and lightweight ultrasound transducers, applied on top of the vacuum bag, send and receive ultrasonic signals from the composite. Due to changes in material properties,the resin flow front and degree of cure can be monitored accurately. Trials to detect porosity and assess structural strength even before form release are ongoing.