Thermally Assisted Prepreg Compaction

Student: Stella Hughes - Master Student

Supervisor: Prof. Pascal Hubert


Out-of-Autoclave prepregs contain dry fiber pathways to ease the removal of air under vacuum bag consolidation. As a result, these materials are initially much thicker when laid up than in their final cured state. This has no bearing on flat or low curvature parts but, when moving towards more complex geometries, it becomes apparent that this high bulk factor of the material prevents the plies from conforming properly during curing.

This work will look at using an elevated temperature debulk strategy to assist with laminate conformation. The advantages of this are two-fold: first, such a process would reduce the resin viscosity during the application of pressure, allowing plies to more readily slip with respect to one another; secondly, the resin infiltrates the tows earlier in the process, decreasing the pre-cure laminate thickness. Together, these aid subsequent plies to be laid up closer to their idealized position. A drawback of using heated debulks is a potential premature advancement of the degree of cure, which could lead to a decrease of interlaminar properties if the crosslinking between the plies is reduced. Thus, a process window must be defined before a heated debulk strategy can be reliably implemented.

Infrared heating scheme for elevated temperature debulks