A transient thermal model within the laser shadow during laser-assisted automated fiber placement: Prediction of temperature at the nip point using a Lagrangian description

Abstract

Automated fiber placement, from a material point of view, involves a transient thermal phenomenon, which introduces additional complexities due to the formation of a laser shadow zone in the optical path. In this study, a transient thermal model was developed within the laser shadow during laser-assisted automated fiber placement, incorporating velocity dependence using a Lagrangian description. This model predicted the temperature history within the laser shadow, thereby enabling control over temperature at the nip point. Experiments were conducted to validate the model by measuring temperatures using a Long Wave Infrared sensor and K-type thermocouples. A good agreement with the experimental results was achieved under various process conditions. The effects of placement speed, laser power, tooling temperature, and roller diameter were analyzed by evaluating both the model predictions and the measured data. Moreover, several composite components were fabricated, and the interlaminar shear strength was tested to characterize the effect of temperature at the nip point. Finally, a temperature at the nip point of 350.5 °C, obtained at a placement speed of 100 mm/s and a laser power of 550 W, yields a maximum value of 59.9 MPa.