Laser-assisted tape winding is an automated process to produce tubular or tube-like continuous fiber-reinforced polymer composites by winding a tape around a mandrel or liner. Placing additional layers on a previously heated substrate and variation in material and process parameters causes a variation in the bonding temperature of fiber-reinforced thermoplastic tapes which need to be understood and described well in order to have a reliable manufacturing process. In order to quantify the variation in this critical bonding temperature, a comprehensive temperature analysis of an adjacent hoop winding process of type-IV pressure vessels is performed. A total of five tanks are manufactured in which three glass/HDPE tapes are placed on an HDPE liner. The tape and substrate temperatures, roller force and tape feeding velocity are measured. The coefficient of variation for each round is characterized for the first time. According to the statistical analysis, the coefficient of variation in substrate temperature is found to be approximately 4.8–8.8% which is larger than the coefficient of variation of the tape temperature which is 2.1–7.8%. The coefficient of variations of the substrate temperatures in the third round decrease as compared with the coefficient of variations in the second round mainly due to the change in gap/overlap behavior of the deposited tapes. Fourier and thermographic analysis evince that the geometrical disturbances such as unroundness and eccentricity have a direct effect on the temperature variation. In addition to the temperature feedback control, a real-time object detection technique with deep learning algorithms can be used to mitigate the unwanted temperature variation and to have a more reliable thermal history.

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The non-uniform temperature and crystallinity distributions present in carbon fiber–reinforced PA12 composite pipes, produced via laser-assisted tape winding (LATW), are investigated in this paper. The width of the laser source is usually larger than the substrate width which causes multiple heating and cooling of some regions of the (neighboring) substrate and hence temperature and crystallinity gradients during the adjacent hoop winding. A kinematic-optical-thermal (KOT) model coupled with a non-isothermal crystallinity model is developed to capture the transient temperature and crystallinity distributions for growing substrate thickness and width. The predicted temperature trends are validated with thermocouple and thermal camera measurements. The substrate temperature varies in the width direction up to 52%. This will lead to extra polymer remelting and possible degradation. The maximum variation of the crystallinity degree across the width is found to be 270% which shows agreement with the trend of the measured crystallinity degree. It is found that a more realistic description of the melting behavior of the matrix is needed to obtain a more accurate prediction of the crystallinity distribution.

Unbonded flexible pipes present a mature technology for the efficient recovery and transport of hydrocarbons offshore. The substitution of metallic reinforcement layers in the multi-layered structure by thermoplastic fiber-reinforced polymer (FRP) presents a solution for self-weight issues of especially long pipes, as FRP materials display high specific strength and modulus while being resistant to external pressure and corrosion. The production of these layers is automated by the laser-assisted tape winding process without the need of additional curing steps. During the manufacturing process, several data like process temperature and consolidation pressure are continuously monitored by non-contact sensors to ensure process stability without interfering in the consolidation process. To gain additional information about the temperature distribution within the multi-layered laminate, contact temperature sensors were introduced in the tape winding process. By this method the temperature of subjacent tapes can be assessed during the continued winding process. Additionally, this paper features a new approach of utilizing winding path data for relating the time-dependent sensor data to the exact position on the produced part. The visualization of path-dependent sensor data opens up possibilities of linking quality monitoring results to manufacturing insufficiencies and potential part defects.