Dr.-Ing.

Janssen, Henning

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  • Publication
    A fully coupled local and global optical-thermal model for continuous adjacent laser-assisted tape winding process of type-IV pressure vessels
    ( 2021)
    Zaami, Amin
    ;
    Schäkel, Martin
    ;
    Baran, Ismet
    ;
    Bor, Ton C.
    ;
    Janssen, Henning
    ;
    Akkerman, Remko
    A numerical process simulation framework is introduced in this paper to describe and predict the process temperature evolution during the laser-assisted tape winding (LATW) process of a type-IV pressure vessel made of glass-reinforced high-density polyethylene (G/HDPE). A local optical-thermal model is fully coupled with a global thermal model for the simulation of continuous adjacent hoop winding cases. The predicted tape and substrate temperatures are compared with the experimental data to validate the process model's effectiveness. The inline temperature was measured by an infrared thermographic camera during the continuous winding. The continuous process temperature of the substrate is affected significantly due to the previously wound layers including the pressure vessel, and a gradual increase of the temperature of the roller and the air inside the liner. A considerable temperature increase calculated as 80-120°C takes place for the substrate during winding of two consecutive layers of (G/HDPE) prepreg tape at the liner ends. The influence of pressure vessel size on the tape and substrate temperatures is investigated for different liner radii using the validated process model. The peak substrate temperature is found to increase approximately 45°C by reducing the radius of the pressure vessel from 272 mm to 68 mm while maintaining all other process conditions constant.
  • Publication
    Process Analysis of Manufacturing Thermoplastic Type-IV Composite Pressure Vessels with Helical Winding Pattern
    ( 2021)
    Schäkel, Martin
    ;
    Janssen, Henning
    ;
    Brecher, Christian
    Composite pressure vessels (CPVs) are widely employed for the high-pressure storage and transportation of hydrogen due to their extraordinary lightweight characteristics. Thermoset CPVs are the market standard due to easy and reliable production. The use of thermoplastic composites for CPV manufacturing via laser-assisted tape winding presents advantages with regard to out-of-autoclave and clean processing, recyclability and design freedom concerning the winding layup. The complex interactions of multiple process parameters like laser power, irradiation incidence angle and tape feed rate along the winding path influence the bonding quality within the composite laminate and require a thorough understanding, especially for helical winding patterns covering cylinder and dome parts of the pres sure vessel. In this work, helical circuits of composite tape were placed on a thermoplastic liner with systematically varied process parameters. The temperature distribution governing the bonding quality between the tape plies was monitored and processed for data analysis. An empirical model characterizing the influences of process parameters on the nip point temperature was created highlighting differences in temperature variation on cylinder and dome parts. Tape feed rate profiles were also taken into account to identify action fields for the development of an optimized process for thermoplastic CPV manufacturing.
  • Publication
    Non-uniform crystallinity and temperature distribution during adjacent laser-assisted tape winding process of carbon/PA12 pipes
    ( 2020)
    Amin Hosseini, Seyed Mohammad
    ;
    Schäkel, Martin
    ;
    Baran, Ismet
    ;
    Janssen, Henning
    ;
    Drongelen, Martin van
    ;
    Akkerman, Remko
    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.
  • Publication
    A new global kinematic-optical-thermal process model for laser-assisted tape winding with an application to helical-wound pressure vessel
    ( 2020)
    Amin Hosseini, Seyed Mohammad
    ;
    Schäkel, Martin
    ;
    Baran, Ismet
    ;
    Janssen, Henning
    ;
    Drongelen, Martin van
    ;
    Akkerman, Remko
    A new global kinematic-optical-thermal (KOT) model is proposed to provide a proper understanding and description of the temperature evolution during laser-assisted tape winding and placement (LATW/LATP) on any arbitrary shaped tooling geometry. Triangular facets are utilized in the kinematic model to define a generic tooling together with a user-defined fiber path and time-dependent process settings such as the tape feeding rate. The time-dependent heat flux distribution on the surfaces is calculated by the optical model and subsequently coupled to the thermal model. The numerical implementation of the developed KOT model is first verified for process simulations of the LATP on a flat tooling by comparing the temperature predictions with the available literature data. To validate the KOT model, a total of four pressure vessels are manufactured with in-line temperature measurements. The process temperature predictions are found to agree well with the measured temperature during the helical winding. The influence of the changing tooling curvature and process speed on the process temperature is found to be significant as shown by the experimental and numerical findings.
  • Publication
    Temperature variation during continuous laser-assisted adjacent hoop winding of type-IV pressure vessels: An experimental analysis
    ( 2020)
    Zaami, Amin
    ;
    Schäkel, Martin
    ;
    Baran, Ismet
    ;
    Bor, Ton C.
    ;
    Janssen, Henning
    ;
    Akkerman, Remko
    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 4.88.8% which is larger than the coefficient of variation of the tape temperature which is 2.17.8%. 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.
  • Publication
    Gesteigerte Zuverlässigkeit für die Herstellung von FVK-Druckbehältern
    ( 2019)
    Schäkel, Martin
    ;
    Janssen, Henning
    ;
    Brecher, Christian
    Druckbehälter aus Faserverbundkunststoff gewinnen für den automobilen Leichtbau zunehmend an Bedeutung. Im Projekt AmbliFibre realisierten Fraunhofer IPT und Partner die Fertigung der komplexen Bauteile austhermoplastischem FVK und stellten mit neuen Simulations- und Qualitätswerkzeugeneine zuverlässige Produktion sicher.
  • Publication
    Increased Reliability for the Manufacturing of Composite Pressure Vessels
    ( 2019)
    Schäkel, Martin
    ;
    Janssen, Henning
    ;
    Brecher, Christian
    Pressure vessels made of fiber-reinforced plastics are becoming increasingly important for lightweight automotive design. In the AmbliFibre project, the Fraunhofer IPT and partners realized the manufacture the complex components from thermoplastic FRP and ensured reliable production with new simulation and quality assurance tools.
  • Publication
    Advanced production of thermoplastic composite pipes
    ( 2019)
    Schäkel, Martin
    ;
    Peters, Tido
    ;
    Janssen, Henning
    ;
    Brecher, Christian
    A novel system for thermoplastic composite tape winding was developed as part of the ambliFibre multinational research project. The system features multiple functionalities for improved quality and reliability in the manufacturing of safety-critical structures such as composite armours for unbonded flexible pipes.
  • Publication
    Temperature analysis for the laser-assisted tape winding process of multi-layered composite pipes
    ( 2019)
    Schäkel, Martin
    ;
    Hosseini, S.M. Amin
    ;
    Janssen, Henning
    ;
    Baran, Ismet
    ;
    Brecher, Christian
    Tubular structures of fiber-reinforced polymer composites are utilized in various applications such as risers in the oil and gas industry and hydrogen pressure vessels in the automotive sector. The laser-assisted tape winding process presents an automated and efficient solution for the manufacturing of these structures out of thermoplastic composites. However, in order to guarantee reliable and high-quality process results, the temperature distribution within the laminate governing the consolidation between successively wound layers has to be understood and taken into account for process design. In an experimental setup, thermocouples were embedded between the layers in multiple spots along the perimeter during the manufacturing of pipe samples with five layers wound on a pure thermoplastic liner. This enabled capturing the through-thickness temperature distribution at different transversal locations. In addition to the temperature data recorded by the thermocouples, a stationary infrared thermographic camera focused on the laser-heated area was mounted on the tape winding head. The temperature data points of both sources were contrasted to evaluate how the through-thickness temperature distribution reflects the temperature input on the surface. Furthermore, the experimentally determined temperature distribution was compared with the results of a numerical process model, drawing conclusions with regard to the modelling and control of the multi-variable process.
  • Publication
    Data Collection and Analysis for the Creation of a Digital Shadow During the Production of Thermoplastic Composite Layers in Unbonded Flexible Pipes
    ( 2018)
    Schäkel, Martin
    ;
    McNab, John
    ;
    Dodds, Neville
    ;
    Peters, Tido
    ;
    Janssen, Henning
    ;
    Brecher, Christian
    Unbonded flexible pipes present a mature technology for the efficient recovery and transport of hydrocarbons offshore. The substitution of metallic reinforcement layers in the multilayered 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.