Modeling of Prepregs during Automated Draping Sequences

The behavior of wowen prepreg fabric during automated draping sequences is investigated. A drape tool under development
with an arrangement of grippers facilitates the placement of a woven prepreg fabric in a mold. It is essential that the draped
configuration is free from wrinkles and other defects. The present study aims at setting up a virtual draping framework capable of
modeling the draping process from the initial flat fabric to the final double curved shape and aims at assisting the development of
an automated drape tool. The virtual draping framework consists of a kinematic mapping algorithm used to generate target points
on the mold which are used as input to a draping sequence planner. The draping sequence planner prescribes the displacement
history for each gripper in the drape tool and these displacements are then applied to each gripper in a transient model of the draping
sequence. The model is based on a transient finite element analysis with the material’s constitutive behavior currently being
approximated as linear elastic orthotropic. In-plane tensile and bias-extension tests as well as bending tests are conducted and used
as input for the model. The virtual draping framework shows a good potential for obtaining a better understanding of the drape
process and guide the development of the drape tool. However, results obtained from using the framework on a simple test case
indicate that the generation of draping sequences is non-trivial.