Process-dependent wrinkle formation for steered tow during automated fiber placement: Modeling and experimental verification

Abstract

In this paper, an experimental study using three groups of different process combinations is first performed to explore the interaction of process parameters with respect to wrinkle formation during tow steering in automated fiber placement (AFP). Furthermore, a process-dependent theoretical model for wrinkle formation is proposed, in which the process dependency is only taken into account for the shear tackiness force based on sensitivity analysis. Closed-form solutions for predicting both the critical steering radius and the stress distribution coefficient are derived. The required model parameters are obtained by experimental tests. In parallel, the correlation relationship between the tangential tackiness force and process parameters is established through the response surface methodology. Thereafter, the model-predicted values for two different steering cases are validated by steering trials. A good agreement between the model-predicted value and the experimental results is observed as the difference is only 2.2% and 3.5%, respectively. Finally, the influence of process parameters on the critical steering radius is discussed and analyzed. It is demonstrated that both the lay-up efficiency and quality for the specific steering constraint could be improved by adjusting the process parameters based on the process-dependent theoretical model for wrinkle formation.