TY - JOUR

T1 - Adhesion-cohesion balance of prepreg tack in thermoset automated fiber placement

T2 - Part 2: Ply-ply cohesion through contact formation and autohesion

AU - Budelmann, D.

AU - Schmidt, C.

AU - Steuernagel, L.

AU - Meiners, D.

N1 - Funding Information: The authors are grateful for the financial support by Deutsche Forschungsgemeinschaft (DFG – German Research Foundation) granted for the research project ‘TackTIC – Tack of Thermoset Impregnated Carbon Fibers’ (project number 458900231 ). The authors also acknowledge the financial support by the Open Access Publishing Fund of Clausthal University of Technology .

PY - 2023/10

Y1 - 2023/10

N2 - Contact formation and autohesion with respect to their role as the major mechanisms governing the tack between thermoset prepregs in automated fiber placement were explored. Therefore, a novel 90° peel test with strictly separated and individually controllable compaction and debonding phases was employed for experimental tack characterization in a rheometer. Variation of compaction pressure, dwell time and temperature enabled the experimental isolation of contact formation and autohesion influences. The experimentally determined tack, ply-ply contact area and resin viscoelastic characteristics were used to parametrize simplified semi-empirical bond strength sub-models that have originally been developed for thermoplastic composite manufacturing techniques. The model prediction was validated successfully within the experimentally reproducible parameter range. Eventually, manufacturing scenarios for thermoset automated fiber placement (AFP) respecting different lay-up velocities (up to 1 m s−1), compaction pressures (up to 10 N mm−2) and both lay-up and mold temperatures (20–60 °C) were assessed in terms of estimated prepreg tack. The implication of both mechanisms, contact formation and autohesion, in the evolution of prepreg tackiness was found to be able to replicate the bell-shaped tack curves proposed by the adhesion-cohesion balance.

AB - Contact formation and autohesion with respect to their role as the major mechanisms governing the tack between thermoset prepregs in automated fiber placement were explored. Therefore, a novel 90° peel test with strictly separated and individually controllable compaction and debonding phases was employed for experimental tack characterization in a rheometer. Variation of compaction pressure, dwell time and temperature enabled the experimental isolation of contact formation and autohesion influences. The experimentally determined tack, ply-ply contact area and resin viscoelastic characteristics were used to parametrize simplified semi-empirical bond strength sub-models that have originally been developed for thermoplastic composite manufacturing techniques. The model prediction was validated successfully within the experimentally reproducible parameter range. Eventually, manufacturing scenarios for thermoset automated fiber placement (AFP) respecting different lay-up velocities (up to 1 m s−1), compaction pressures (up to 10 N mm−2) and both lay-up and mold temperatures (20–60 °C) were assessed in terms of estimated prepreg tack. The implication of both mechanisms, contact formation and autohesion, in the evolution of prepreg tackiness was found to be able to replicate the bell-shaped tack curves proposed by the adhesion-cohesion balance.

KW - Automated fiber placement

KW - Carbon fiber

KW - Cohesion, interface

KW - Epoxy resin

KW - Prepreg

UR - http://www.scopus.com/inward/record.url?scp=85170405889&partnerID=8YFLogxK

U2 - 10.1016/j.jcomc.2023.100396

DO - 10.1016/j.jcomc.2023.100396

M3 - Article

AN - SCOPUS:85170405889

VL - 12

JO - Composites Part C: Open Access

JF - Composites Part C: Open Access

SN - 2666-6820

M1 - 100396

ER -