Thesis defense of Ivan Saenz

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Thesis defense of Ivan Saenz

Thesis

Thesis defense of Ivan Saenz

Title of the thesis: Pultrusión basada en el curado UV fuera del molde: Desarrollo de Componentes dirigidos a la industria de la Automoción. Obtained the SOBRESALIENTE CUM LAUDE qualification.

2019·05·20

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  • Title the thesis: Pultrusión basada en el curado UV fuera del molde: Desarrollo de Componentes dirigidos a la industria de la Automoción.
  • PhD programme: DOCTORATE PROGRAMME IN MECHANICAL ENGINEERING AND ELECTRICAL ENERGY
  • Thesis directors: Jon Aurrekoetxea Narbarte and Iosu Tena Merino
  • Court:
    • President: Maria Lluisa Maspoch Ruldua (CENTRE CATALÀ del PLÀSTIC)
    • Vocal: German Castillo Lopez (Universidad de Malaga)
    • Vocal: Joseba Koldo Gondra Zubieta (GAIKER)
    • Vocal: Alberto Lopez Arraiza (Universidad del País Vasco)
    • Secretary: Mª Asunción Sarrionandia Ariznabarreta (Mondragon Unibertsitatea)

Abstract

The requirements of the automotive industry for safety and energy efficiency have placed composites on the strategic agendas of all manufacturers. However, the low productivity of manufacturing processes in addition to their high cost has limited their use to high value-added applications. Thus, over the last few years, numerous advances have been made in the search for new processes that allow the manufacture of composites in a profitable manner. An example of this is pultrusion based on ultraviolet (UV) curing outside the die. This new approach consists of curing the profile at the exit of the die with UV radiation, which makes it possible to reduce pulling forces, simplify the dies and manufacture curved profiles with a robotic pulling system. The studies related to this process demonstrated its viability and laid the foundations of the technology, envisioning its potential to be incorporated into the Basque industrial fabric and meet the requirements of the automotive industry. However, this fact requires a greater understanding of the limits of the process and of the technology itself. Therefore, this work has focused on the generation of knowledge in three fundamental blocks:

  • The first block is aimed at developing new photo-curable formulations. The main objective is to develop formulations that provide an increase in mechanical properties with respect to current profiles. For this purpose, a comparison is made between the formulation used in the studies prior to this work and two new formulations, one of unsaturated polyester and one of vinyl ester. The vinyl ester formulation represents a significant increase in the mechanical properties of the profiles. In addition, in this block is demonstrated the feasibility of curing by UV radiation composites with tri-hydrated alumina, being a step prior to its incorporation into profiles manufactured by UV pultrusion.
  • The second block focuses on the development and validation of a kinetic model capable of predicting the evolution of the degree of cure through the thickness of the composite during the UV curing process. The main objective of this block is to have an analytical model for the simulation of the UV pultrusion process, which would reduce the set-up times of the machine. To achieve this goal, an optical model, which divides the intensity into discrete values of wavelength, is combined with the autocatalytic model. This approach considers all factors affecting UV curing, such as the UV light source, composite material and thickness, as well as the photoinitiator system.
  • The third block is oriented to the design of cellular composite structures for energy absorption in impact cases. The main objective of this block is to analyse the feasibility of predicting the behaviour of the component by characterizing the unit cells that compose it. The results demonstrate the viability of this strategy, as long as the design is made based on the results of the dynamic tests.

Finally, a business model has been developed in which the automotive industry has been established as a potential customer. This analysis has studied, from a business point of view, the viability of the technology to deal with this industry. The conclusion obtained in this analysis and the results obtained in this PhD thesis have set in motion the necessary mechanisms for the creation of a Startup based on the UV pultrusion process.