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• Advanced thermal control of VARI process with self-heating mold

  M. Escolano, I. Conde, M. Lizaranzu, J. Rodríguez, J. Orús, F. Martín-de-la-Escalera, M. Laspalas

  Materiales Compuestos (2025). Vol. 09 - Comunicaciones MatComp25 (2025), (Núm. 1 - Fabricación y Aplicaciones Industriales), 40

  
  

  Abstract

  Manufacturing liquid composites with thermoset resins requires precise temperature control throughout the process. In the specific case of vacuum infusion (VARI) in a self-heating mold, one side of the part is in contact with the mold, which is the one that incorporates the heating elements (resistors), while the other side is in contact with the consumables (peelable, bleeder, mesh, vacuum bag), which imposes a substantially different thermal condition that can create thermal gradients. In order to achieve the greatest possible thermal uniformity, not only throughout the length of the part, but also throughout its thickness, additional external heating elements are usually incorporated. In the present work, the thermal control of an infusion process of a leading edge section of a horizontal stabilizer of an aircraft is developed. This control has been developed using the MPC (Model Predictive Control) method, which allows applying the necessary power to the heat sources independently to control the temperature at the measurement points, based on predictions obtained from a reduced-order thermal model (MOR). This reduced representation has been generated using the POD (Proper Orthogonal Decomposition) technique from the thermal matrices obtained from a finite element simulation (FEM) model of the prototype mold, previously adjusted and validated. In order to detect and compensate for the nonlinear behaviors present in the system, mainly due to convection, a perturbation estimator using a Kalman filter is implemented. In addition, the reduced-order model allows a thermal representation of the complete system to be obtained, which facilitates the implementation of virtual sensors in a way that controls not only the temperature at the measurement points, but also at points of the part that would not be possible to monitor with physical sensors, helping to maintain a homogeneous temperature distribution in the material during the manufacturing process. The control scheme has been experimentally validated on the prototype mold, obtaining precise monitoring of the temperature profile and complying with the manufacturing standards of the part.

  Abstract
  Manufacturing liquid composites with thermoset resins requires precise temperature control throughout the process. In the specific case of vacuum infusion (VARI) in a self-heating [...]

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