The student Pablo Sánchez Barros obtained an OUTSTANDING qualification with 'INTERNATIONAL DOCTORATE' mention
The student Pablo Sánchez Barros obtained an OUTSTANDING qualification with 'INTERNATIONAL DOCTORATE' mention
The student Pablo Sánchez Barros obtained an OUTSTANDING qualification with 'INTERNATIONAL DOCTORATE' mention
Thesis title: Advanced numerical models in rubber pad diaphragm forming process simulation
Court:
- Chairmanship: Marta Oliveira (Universidade de Coimbra)
- Vocal: Jenny Venema (Tata Steel, Research & Development)
- Vocal: Mikel Isasi Iriondo (Leartiker)
- Vocal: Iñigo Llavori Osa (Mondragon Unibertsitatea)
- Secretary: Eneko Sáenz de Argandoña Fernández de Gorostiza (Mondragon Unibertsitatea)
Abstract:
In a conventional way, sheet metal products are manufactured using rigid tools, that is, which must be completely aligned and fit perfectly together. This technology has been widely used in the forming of sheet metal products, allowing the manufacture of large batches of parts continuously and quickly. On the other hand, the tools used in these processes are expensive and require long reconfiguration times.
Conventional processes are therefore very useful in sectors where large batches of parts are continuously manufactured, which amortizes the preparation time and cost of the tools, as occurs in the automotive industry. However, in the sheet metal products demanded by the aeronautical sector, a greater variety of geometries is generally demanded and in lower quantities, making these processes unsuitable.
Due to these particular needs of the aeronautical sector, the rubber forming processes arise. In this type of processes, instead of using a set of rigid tools, only a rigid die will be used, and as a counterpart a flexible rubber tool, which may be compatible with different dies.
Rubber pad diaphragm forming process is a rubber forming process, which unlike the conventional technologies in this field, makes use of a combination of a flexible, a rigid tool, and fluid pressure, in order to get the parts. In this process, a rubber diaphragm is pushed by the action of a fluid under pressure, which, when deformed, will press the sheet against a rigid tool, forcing it to acquire the geometry of said tool. Due to its nature, this process is specially designed for the manufacture of multiple short series of parts, being the aeronautical sector the target industry.
Compared to conventional forming processes, where rigid tools are used and around which an extensive bibliography and expertise has been developed over the years, the rubber pad diaphragm forming process, is in a much more preliminary state.
Added to this, despite the fact that the simulation of more conventional forming processes is very advanced and it is actively implemented in the production means, the inclusion of rubber has made the rubber forming processes simulations lag behind. Much of the industry that uses this process either does not use numerical simulations or uses the same kind of models as it would be used for the hydroforming processes.
The central points of this work will be, on the one hand, the analysis of the hyperelastic behaviour of the rubbers and the different effects that take place on them, as well as evaluating how they interact with the other elements during the process and affect the result of the final piece. On the other hand, we have the advanced characterization of the mechanical properties of the metal sheet and the friction coefficient during the process.
In this way, the development of advanced simulation models and the characterization of all the elements that intervene in the process, as well as their correct modelling, will be a key element to understand better this technology, and increase the knowledge around the process, with the final goal of optimize the daily work with this kind of technology.