Session: 18-01 Advanced Manufacturing and Design I

Paper Number: 127515

127515 - Numerical Investigation of Different Forming Approaches for the Manufacturing of
Titanium Bipolar Plates for the Aviation Industry 

The mobility sector is one of the largest contributors to greenhouse gas emissions in the European Union. One approach to reduce these emissions and thereby reach the climate goals set by the European union is the use of alternative propulsion concepts, such as the fuel cell. Due to their high power to weight ratio, fuel cells are well suitable for the electrification of aircrafts, especially compared to heavy battery systems. However, the economic and ecologic feasibility of the hydrogen fuel cell depends on its performance which in turn is largely determined by the volumetric flows of reactants conveyed within the cell. In this context, a key component for the performance is the bipolar plate, as its channel geometry defines the volumetric flows of reactants. The implementable channel geometry, however, is limited by the plastic deformation capacity of the material being used, the springback occurring after forming as well as the manufacturing process used. During forming the material experiences plastic deformation, resulting in material thinning and stress. Once a critical thinning is reached, the channel will tear. To meet the safety standards of aviation, the thinning of the component must be decreased while for a high power density the geometry of the channels must be met. Bipolar plates are industrially manufactured using the processes of embossing, rubber pad forming and hydroforming.

In this paper, three different manufacturing methods are investigated numerically regarding their feasibility for the use in bipolar plate manufacturing for the aviation industry. Therefore, the forming process of a critical bipolar plate feature is simulated three dimensional for the embossing, rubber pad forming and hydroforming. All forming processes are numerically modelled using Abaqus CAE. The material used is sheet metal of type titan grade 1 with a thickness of 100 µm. To evaluate the suitability of the regarded manufacturing processes, the results are compared in terms of form filling, material thinning as well as stress states. The stress states are evaluated using the lode angle parameter, the triaxiality and the Von Mises equivalent stress. The form filling is represented by a mean square error comparing the numerical results with the feature geometry.

Presenting Author: Jan Sommer Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University

Presenting Author Biography: Research associate at the Laboratory for Machine Tools and Production Engineering (WZL). Research Field: Manufacturing of bipolar plates with the focus on forming processes.

Authors:

Jan Sommer Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University
Max Meerkamp Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University
Martina Müller Laboratory for Machine Tools and Production Engineering (WZL)
Rainer Horstkotte Fraunhofer Institut für Produktionstechnologie IPT
Sascha Gierlings Fraunhofer Institut für Produktionstechnologie IPT
Tim Herrig Laboratory for Machine Tools and Production Engineering (WZL)
Thomas Bergs Laboratory for Machine Tools and Production Engineering (WZL)