Analysis of the Rotation Bending Test Method and Characterization of Unidirectional Carbon Fiber-Reinforced...

Area of Science:

• Materials Science
• Polymer Engineering
• Composite Materials

Background:

• Bending is a key deformation mechanism in unidirectional (UD) thermoplastic tape forming.
• Accurate experimental data at processing temperatures are vital for process simulation and material modeling.
• Thermoplastic matrix is molten at processing temperatures, significantly affecting material behavior.

Purpose of the Study:

• To accurately characterize the temperature-dependent bending behavior of carbon fiber-reinforced polycarbonate (PC/CF) UD tapes.
• To investigate single and multi-ply specimens within their processing temperature range.
• To analyze and compensate for systematic deviations in rotation bending tests.

Main Methods:

• Utilized a rotation bending test with a customized fixture.
• Employed analytical methods, experimental investigations, and finite element modeling (FEM).
• Evaluated a compensation method for the toe-in effect to ensure data reliability.

Main Results:

• Obtained reliable bending resistance data for PC/CF UD tapes within the processing window.
• Identified a major drop in bending resistance between 200 °C and 250 °C.
• Observed a less significant decrease between 250 °C and 300 °C, with thickness-normalized data indicating non-linear thickness-moment relationships and increased shear dominance at higher temperatures.

Conclusions:

• The study successfully characterized the temperature-dependent bending resistance of PC/CF UD tapes.
• The compensation method effectively addressed systematic deviations in the rotation bending test.
• The findings provide crucial data for understanding and simulating the forming of these composite materials at elevated temperatures.