Session: 03-01-01: Advanced Manufacturing

Paper Number: 187951

187951 - Toward Optimization of Compaction Rollers for In-Situ Consolidation Automated Fiber Placement of Thermoplastic Composites 

In-situ consolidation with Automated Fiber Placement (AFP) of thermoplastic composites (TPC) offers significant potential for rapid and scalable aerospace manufacturing. However, achieving consistent interlaminar bonding and mechanical performance remains a critical challenge due to the short processing windows achieved by AFP, which uses laser or conduction heating and roller pressure. This research investigates the optimization of new key parameters in AFP, namely compaction roller geometry and compliance. Process conditions were controlled by maintaining a constant layup speed of 125 mm/s and a constant robot-applied compaction force of 400 N, while laser power was systematically varied to evaluate its influence on thermal input and consolidation behavior. These parameters are optimized through experimental testing, finite element analysis (FEA), and hardware optimization. The primary objective of this research is to improve short beam shear (SBS) strength for in-situ consolidated AFP plates, as a measure of interlaminar consolidation quality.   

A series of silicone-based compaction rollers with varying shore hardness, silicone thickness, and aluminum core diameters was designed, fabricated, and experimentally evaluated. Three initial roller configurations were tested, and the resulting pressure distributions and SBS responses were systematically analyzed to identify governing relationships between compliance, contact width, and pressure uniformity. These data-driven correlations and performance trends were subsequently incorporated into the design and fabrication of a fourth roller featuring optimized geometry and material compliance. Experimental results demonstrated enhanced consolidation behavior and a measurable increase in SBS strength for in-situ consolidated specimens produced with the optimized roller configuration. Pressure-sensitive films and force sensors were used to quantify contact pressures and verify repeatability across trials.  

In order to better understand the interaction between the roller and the tape’s surface, nonlinear FEA simulations were conducted using hyperelastic material models for polydimethylsiloxane (PDMS) rubber (roller) and linear elastic models for aluminum cores. A five-parameter Mooney–Rivlin formulation was implemented to approximate silicone behavior under compression. The contact interactions were modeled with frictional surface-to-surface constraints. Mesh convergence studies and Richardson extrapolation techniques were applied to ensure numerical stability and solution convergence. The simulation outputs, which include displacement fields, contact pressures, and nodal forces, were compared with experimental sensor data. The results illustrated an acceptable correlation for select roller configurations, validating the predictive capability of the model within acceptable error margins.  

Overall, this study demonstrates the ways in which roller compliance, thermal input, and localized pressure distribution are highly sensitive in AFP fabricated thermoplastic composites. The integration of experimental force sensing with validated FEA provides a framework for predicting consolidation behavior and guiding AFP hardware design decisions. The outcomes contribute to the advancement of scalable AFP manufacturing strategies by establishing practical guidelines for roller geometry selection. Future work will extend these findings through continued optimization of compaction roller design, including the development of larger-diameter rollers and refined material compliance to achieve more uniform pressure distribution and improved interlaminar bonding.

Presenting Author: Jenny Ruiz University of California, San Diego

Presenting Author Biography: Jenny Ruiz is a structural engineering graduate student with a focus on advanced composites, finite element analysis, and aerospace structures. She has hands-on experience in automated fiber placement research, composite manufacturing, and structural testing. Her work bridges analytical modeling with practical fabrication. Jenny is passionate about high-performance engineering, sustainable materials, and contributing to innovative aerospace and flight-hardware development.