World-renowned for automotive quality and safety, Daimler’s Mercedes-Benz cars are also highly innovative. To share the inside story, Dr. Jürgen Kohler, the head of NVH CAE and Vehicle Concepts at Daimler AG, will talk about “High-Performance Computing – Highly Efficient Development – Mercedes-Benz Cars” at the opening keynote at this year’s ISC High Performance conference.

ISC: How long has Mercedes-Benz been employing high-performance computing for designing vehicles? And what motivated Daimler to turn to CAE and HPC-based simulations? 

Kohler: Mercedes-Benz first started with its simulation activities in research and development back in the 1960s. At first, programs for the industrial application of the finite element method were self-developed in-house to support, for example, the elastic-static design of the vehicle structure by computational means. Later on the company switched to the commercial FE program, NASTRAN when it was first offered on the market. There are various versions available today and we use NX NASTRAN. So with the use of more detailed models to consider all relevant design details, the access to HPC became compulsory for us. It was also equally necessary to get the analyses results back in an “acceptable” amount of time. In the past, we had to wait several days; today we are able to obtain results overnight.

ISC: How has the use of simulations changed the development and manufacturing of automobiles?

Kohler: Our so called “Digital Prototype” has been integral to the work of Mercedes-Benz Cars Development for over a decade now. The company realized early on that complex vehicle design can only be achieved through the intensive use of simulation tools in closest interaction with precise and complementary testing. Today CAE has become an indispensable part of modern development processes for us and an integral component alongside design, testing, and trials. This was undoubtedly triggered by the challenge of designing ever-more complex vehicles to a high degree of maturity over an acceptable period of time, and without the need for expensive trial phases.

ISC: How powerful are the compute clusters that Mercedes-Benz uses for vehicle development?

Kohler: The computing models are constantly getting more complex and bigger because they now also map localized details geometrically and physically. To ensure that this does not impact the turnaround times in day-to-day development work, cost-optimized high-performance computers are deployed, which can keep pace with these demands. This is why Mercedes-Benz Cars Development uses high-capacity compute clusters, consisting of a number of multi-CPU machines with sufficient RAM and capacity. For example, when simulating NVH – noise, vibration, and harshness – we can run more than 400 demanding full-vehicle jobs per day, where one run involves calculating 8,000 modes from a 30 MDOF matrix.

ISC: What could be gained from more powerful computers if vehicle developers had access to such systems?

Kohler: What could be gained are of course are more robust simulations, more optimization runs, and more detailed models. At Mercedes-Benz Car Development we ensure that our CAE engineers have access to computers which have the power needed to fulfill their analyses tasks according to the demands and the timelines of the car development processes. The computational work is mainly done on cost-optimized, high-capacity computer clusters in-house. When needed, access to external HPC capacity is available.

ISC: Is the software used for these simulations acquired from ISVs, derived from open source components, or developed in-house?

Kohler: The software tools in use are mostly commercial ones that are available on the market. For example we use LS-DYNA for crash simulations, NX NASTRAN with CDH/AMLS for NVH, STAR CCM+ for CFD or LMS Virtual Lab for chassis simulations. In general we are in close interaction with the ISVs in order to include for example new features in the codes which we need in our models to keep pace with new material technologies in short loops or to further enhance the efficiency of the code. Furthermore in the ASCS, the Automotive Simulation Center Stuttgart, we cooperate with other OEMs like Porsche and Opel in the precompetitive phase, in addition to several highly experienced ISVs, IHVs, engineering companies and partners from universities like HLRS, the High Performance Computing Center Stuttgart. Together with more than 20 partners, we develop methods, for example, for more robust crash simulations, optimization of combustion, and thermal simulation of batteries.

ISC: German engineering is quite focused on mechanical designs and mechanics. In your opinion, is this a strength or does Germany have a lesson or two to learn from Japan that relies on electronic engineering and robotics?

Kohler: In January this year, at the Consumer Electronics Show in Las Vegas, Mercedes-Benz presented its new research car “F 015 Luxury in Motion”, which drove autonomously through Las Vegas to the show hall, attracting a lot of attention from the audience. I don’t feel that we have to learn further lessons, but we have to do our jobs right to fulfill the ambitious targets we have set for ourselves for the future.