The paper presents an overview of the tape-laying process for thermoplastic matrix composites and the current state-of-the-art simulation of this process. As the current mathematical description of the process is partly based on a Newtonian shear flow and thermoplastics normally show a shear thinning behavior at higher shear rates, the assumption of a Newtonian shear flow has been verified. Therefore, the occurring shear rates have been calculated and compared with the data of a viscosity plot for a polyether ether ketone material. As a result of this analysis, the assumption of Newtonian shear flow is shown to be an oversimplification. (c) 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E705E713, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21312