Compression moulding of Randomly-Oriented Strands (ROS) of pre-impregnated thermoplastic composites
is a process that enables the forming of complex parts with features such as ribs, thickness variations
and holes in one single moulding step. This paper focuses on the macroscopic squeeze flow behaviour
that occurs during forming. This mechanism rules the filling of intricate features of the mould initially
empty. A 2D Finite Element model was developed to predict the squeeze flow of ROS composites. The
material was modelled as a Bingham fluid and the equivalent viscosity and yield stress of three different
strand sizes were determined using an inverse method. The viscosity and yield stress were found to
increase with strand length. Experimental validation of the model was performed using Carbon/PEEK
ROS flat samples and the average difference between experimentally measured and predicted final strain
was below 5% for all cases.