Squeeze flow visualization using digital image correlation

Process modeling of thermoplastic composites is vital to process optimization. One of the process phenomena that needs to be characterized for modeling is the flow of fibers and matrix transverse to the fiber direction, typically characterized using the squeeze flow method. The determination of the transverse viscosity from squeeze flow data requires assumptions of boundary conditions and velocity profiles, which are difficult to determine during or after the test. This work presents a methodology to determine boundary conditions and flow profiles during the squeeze flow of UD C/LM-PAEK material by means of digital image correlation (DIC). Image sequences of two experiments were analyzed, one performed at a rate of 0.01 mm/s and the other at 5.0 mm/s. The analysis showed differences in the boundary conditions and flow fields both across different test conditions and during each individual test. These new insights will help improve the kinematic accuracy of flow models fitted to squeeze flow characterization data.