We are all well aware that Automotive companies around the world today are confronted with the challenges of legislation calling for significant gains in fuel economy and reductions in tailpipe emissions in the coming years. Vehicle lightweighting is one of several strategies being employed to meet these targets, and virtually everything in the vehicle is a potential candidate. Audi’s initiative for vehicle lightweighting, “Audi ultra”, has successfully reversed the weight spiral – the tendency for successive vehicle models to get heavier and heavier from one model year to the next. The most recent A3 and A6 models from Audi are up to 80 kg lighter than their previous releases.

In this presentation from the 2013 SIMULIA Community Conference, Tamas Schmidt of the Engine Development department at Audi in Hungary discusses the introduction of short fiber reinforced plastic components into powertrain assemblies. Doing so at Audi has contributed to a 3.5 kg weight savings in the gasoline engine for the A3, as compared to its predecessor. While the potential weight savings certainly are attractive, Mr. Schmidt emphasizes that, from a simulation perspective, you really cannot handle these components in the same manner as if they were made of metal. For instance, the injection molding process introduces material anisotropy that must be considered. In one example, he shows differences of 60-70% in predicted stresses between considering a component as isotropic versus the more accurate anisotropic model.

And so his presentation focuses, at a high level, on the simulation processes Audi has developed and adopted to address short fiber reinforced plastic powertrain components. From mapping of fiber orientations from the injection molding simulation results onto the Abaqus structural model, to meshing considerations, damage/failure prediction, model validation, and usage of Isight to help automate material model calibration, this presentation gives a good overview of the simulation aspects that need to be tackled. Certainly worth your time to give this a look if short fiber reinforced plastic components are in your future.