Resin percolation and intimate contact in fast processing of thermoplastic composites

Fusion bonding of thermoplastic composites (TPCs) requires intimate contact before polymer interdiffusion and solidification can establish an interlaminar bond. The lack of such intimate contact results in voids or disbonds. This study showed through cross-sectional imaging and scaling analysis that percolation flow, rather than squeeze flow, of resin through fibers is the dominant mechanism to achieve intimate contact in rapid TPC processes such as automated fiber placement (AFP) and welding. A 1D intimate contact model based on resin percolation, derived from Darcy's Law, is presented and compared to experiments. While this model proved effective in comparing processing conditions by adeptly capturing trends, it under-predicted resin content in samples processed using AFP with low pressure. The model was extended to high processing rates. In-situ high-speed imaging and ex-situ microscopy revealed void size and morphology based on AFP processing parameters. The results of this study can guide fast processing of thermoplastic composites.

Name thesis:degree_name

Master of Science in Engineering

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

The University of Texas at Austin

Year dc:date.issued

2025

Author dc:creator

• Kirchhoff, Joseph

Advisors dc:contributor.advisor

• Tehrani, Mehran
• Ghattas, Omar N.

• Intimate contact
• Resin percolation
• Thermoplastic consolidation
• Automated fiber placement

Identifier URI

https://doi.org/10.26153/tsw/62048

OAI identifier oai:identifier

oai:repositories.lib.utexas.edu:2152/134726