Laser-assisted tape winding/placement (LATW/P) is a process in which fiber-reinforced thermoplastic prepregs are heated by a laser source and in-situ consolidated by a compaction roller. Maintaining a constant temperature along the prepreg width prior to the nip point is utmost necessary to manufacture fiber-reinforced thermoplastic composites with proper bonding quality. The heat flux distribution on the incoming prepreg tape and already placed substrate is affected by the local geometry and variation in process parameters during the process. In order to maintain the processing temperature distribution at the desired conditions, a new process optimization approach for the laser power distribution is presented. A laser source with variable power distribution is considered in the optimization scheme which can improve the bonding quality of the final product by achieving the desired constant nip point temperature distribution. The variable laser power distribution can be realized practically with the Vertical-Cavity Surface-Emitting Laser (VCSEL) technology. An inverse optical and thermal process models are developed in which an ideal laser power distribution is calculated based on the surface temperature distributions on the tape and substrate described as an input to the process model. Two different optimization studies are performed based on two different input temperature profiles namely stepwise and linearly ramp profile. First, the inverse thermal model is used to calculate the required heat flux distribution which is forwarded as an input to the inverse optical model. The obtained heat flux distribution is transformed into the laser power distribution using the optical model in which the ray-tracing method is used. The relation between the surface temperature distribution and laser power distribution is investigated. The obtained laser power distribution using the inverse optical model is compared with the calculated laser power distribution as an input for the already developed optical-thermal model.

A new inverse kinematic-optical-thermal (IKOT) model is introduced to control the process temperature in laser assisted tape winding and placement processes. The optimum time-dependent laser power distribution is obtained by employing a grid of independent laser cells while keeping the temperature of substrate and tape at the target temperature. Multi-layer cylindrical hoop winding with laser grids of 1 × 1, 28 × 1, and 28 × 11 and helical winding of a pressure vessel with laser grids of 22 × 1 and 22 × 11 are considered. It is found that the optimized laser power distribution pattern remains the same during the consecutive hoop winding process while the total power reduces to compensate the heat accumulation. A more non-uniform laser power distribution is obtained for the helical winding because the substrate curvature changes drastically at the dome section of the pressure vessel. The change in the optimum total laser power is found to be almost constant for the helical winding case. Finally, the IKOT model is evaluated by analyzing the effect of the computational parameters on the optimized process temperature.