Title: Folded and Unfolded Wrinkle Formation During Steering Using an AFP Tabletop Simulator

Authors: Ryan Pederson, Nima Bakhshi, Adam Clare, Anoush Poursartip

DOI:

Abstract: The potential of Automated Fibre Placement is limited by the propensity to develop defects, particularly when the tows are steered. In this work we use comprehensive video imaging to study the formation of folded and unfolded wrinkles during AFP steering. This is done by using a table-top AFP simulator that provides clear and close access to the roller area, with cameras placed in front and behind the nip-point, as well as other imaging to capture post-deposition growth. To encourage folded wrinkle growth, and to allow close-up imaging, the tow feed was moved away from the nip-point. Under identical conditions, both folded and unfolded wrinkles can form due to the excess length generated in steering. In the case of folded wrinkles, a widthwise oscillation of the tow is initiated ahead of the nip-point of the roller. When an oscillation happens to be of just the right amplitude, width, and location across the width of the tow, it is caught and folded over as it goes through the nip. This folded wrinkle emerges out of the back of the roller in a flattened state and immediately starts growing to a final size. Conversely, an unfolded wrinkle shows lift-off from the roller, but this is uniform across the width, with a maximum at the inner edge. Consequently, there is no mechanism that leads to a crease or foldover. As the tow exits from the roller, the tow is fully compacted onto the substrate, and there is a delay before an unfolded wrinkle initiates and grows to a final size.

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Conference: SAMPE 2026

Publication Date: 2026/04/27

SKU: 155

Pages: 11

Price: $22.00