About this Abstract |
Meeting |
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
Symposium
|
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
Presentation Title |
Extensional Viscosity and Microstructural Evolution of Highly Aligned Discontinuous Fiber Composites in Forming |
Author(s) |
Thomas A. Cender, Pavel Simacek, John W. Gillespie, Suresh G. Advani |
On-Site Speaker (Planned) |
Thomas A. Cender |
Abstract Scope |
The longitudinal extensional viscosity of a highly aligned discontinuous fiber (ADF) thermoplastic matrix composite is investigated to develop a model and validate microstructural evolutionary mechanisms. Samples stretched at constant temperature and strain rate are shown to exhibit shear thinning a strain softening behavior. Material microstructure was investigated with X-ray CT and optical micrographs to show that the composite microstructure deconsolidates before forming and continues to evolve with deformation. A unit cell micromechanical model is modified to includes the effect of fiber spacing variability, fiber overlap reduction, and deconsolidation. Calibration of the model reveals that matrix shear strain rate is an order of magnitude higher than previously predicted due to local fiber spacing. This effect is captured by a fiber spacing variability parameter which scales average spacing down by an order of magnitude. The model is able to accurately predict peak extensional viscosity, resulting from a Carreau fluid polymer viscosity model, as well as offer insights into the mechanisms of strain softening. |
Proceedings Inclusion? |
Definite: Post-meeting proceedings |