Towards an accurate process design tool for laser-assisted tape winding

Laser-assisted tape winding (LATW) is an automated process to manufacture tubular fiber reinforced thermoplastic composites such as flywheels rings, pipes, and pressure vessels. The pre-impregnated tapes are bonded to the substrate using a compaction roller and a laser heat source based on the in-situ consolidation mechanism. Multiple physical phenomena take place simultaneously during the LATW process, including kinematics, optics, and heat transfer. The main goal is to develop a generic and quantitatively accurate process design tool leading to predictable part properties suited for product and process optimization with a focus on the process temperature evolution.

Firstly, a coupled kinematic-optical-thermal (KOT) model is presented to predict the temperature evolution during multi-layer hoop winding. The continuing heat accumulation during consecutive winding resulted in a gradually increasing process temperature which was also observed by the thermal camera measurements. The roller deformation altered the temperature field by changing the heating length and heat flux distribution. Next, the adjacent hoop winding process used to manufacture composite pipes was studied. Multiple heating and cooling cycles at the substrate edges result in a nonuniform temperature distribution along the substrate width. The obtained temperature history was used in a nonisothermal crystallinity model to predict the degree of crystallinity distribution. Afterwards, a generic KOT model was developed for an arbitrary tooling geometry and winding pattern. Helical winding of the dome part of a pressure vessel was studied by incorporating a varying local tooling curvature and a winding speed. The process temperature changed up to 17-20% due to the increased local surface curvature and process speed validated with the thermal camera measurements. Finally, an optimization framework was introduced by using an inverse KOT (IKOT) model. The optimal laser power distribution was obtained using a grid of independent laser cells. The optimized laser power distribution pattern remained the same during the hoop winding process while the total power reduced. A more non-uniform time-dependent laser power distribution was obtained for the helical winding case.

The roadmap towards achieving an accurate process design tool for the LATW processes is evaluated at the end for any tooling geometry, winding angle and process parameters.