MODEL THE COMPLEXITY
Building a premium ride as standard
A reputation built on quality and delivered with simulation
By Luke Morris
Image provided by Daimler Truck
Mercedes-Benz was founded nearly 100 years ago and throughout that time the name has always been synonymous with quality and style. No surprise then that it was recognised as the world’s most valuable premium automotive brand in a 2019 study by Interbrand.
But attaining and maintaining such an accolade doesn’t come easily. Especially since the company has broadened their product range over the years by acquiring brands such as Daimler Truck. Any vehicle associated with Mercedes must live up to the premium, luxury expectations. It’s not enough to look good and perform well – features such as reliability, ride, comfort, and integrated technology are all essential.
There’s also the not-so-small matter of needing to continue developing conventional thermal engine powered vehicles alongside fuel cell and electric powertrains. And did I mention autonomous vehicles and all the extra electronics and sensors needed to enable platooning or self-driving?
All these factors are critical to the continued success of the brand, but comfort is arguably most important in distinguishing Mercedes products apart as luxurious. Customers expect to feel the premium quality as soon as they get behind the wheel, and the best way to deliver this is by reducing the noise, vibration, and harshness (NVH) experienced.
Revolution with simulation
Mercedes has been using Simcenter Nastran software for NVH engineering since 2004 to meet its lofty targets in this area.
Simcenter Nastran is a premier finite element analysis (FEA) solver for dynamics, NVH, and structural analysis. Essentially, it allows engineers to optimize NVH performance without the need for building countless prototypes that cost significant time and money.
In the past, optimization was limited as each change required a new prototype to verify improved performance. There’s only so many resources that can be allocated to designing each model so compromises had to be made in order to get products to market within a reasonable timeframe.
Simulation has revolutionised this. Engineers can now simulate individual components or complete vehicles to understand exactly how they will vibrate when in operation and how this will impact on driver and passenger comfort. These digital models can be built and tested in a matter of days – much faster and cheaper than physical testing – meaning that more design iterations can be processed, and more ideas explored to reach the optimum designs.
This couldn’t be achieved with just any simulation tool. Engineers need to be confident that the prediction quality of simulation is at least as accurate, if not more so, than physical testing. Mercedes uses Simcenter Nastran because it can efficiently handle large models with up to 30 to 50 million degrees-of-freedom (DOF). It also simulates engine, road, and wind noise, and covers a large number of load cases over a broad frequency range.
Image provided by Daimler Truck
Another reason Mercedes has continued using Simcenter Nastran for so long is the ease of integrating third-party software tools in pre- and postprocessing.
Glue connections allow engineers to more easily model the interface between the structural model and fluid model. And model reduction techniques such as the Craig-Bampton methods enable the easy exchange of data on supplied components and vehicle behaviour without exposing valuable intellectual property – vital to making progress without giving away design secrets.
Most importantly, Simcenter Nastran has been consistently matching the results from physical testing, giving engineers confidence to trust simulation and increase its use throughout the development process.
Extending simulation further
Following on from the proven success of simulation, Daimler Truck has recently adopted Simcenter STAR-CCM+ to develop the next generation of CO2-neutral vehicles.
By transforming its CAE development process to a full digital twin-driven Multiphysics environment, Daimler will be able to simulate all the fluid and thermal aspects of design.
Did you know over 52% of fuel use is down to the engine power needed to overcome wind resistance? Simulation enables the improvement of aerodynamic performance and thus reduces emissions even before moving away from thermal engines. And when it comes to optimizing electric powertrains, Simcenter STAR-CCM+ allows engineers to look at multi-attribute trade-offs to minimize energy usage while maintaining performance and ensuring efficient cooling of batteries and electronics.
Oh, and they will also be able to improve that all-important comfort factor further. Multi-phase simulation helps to reduce soiling on side windows, mirrors, and sensors, improving user visibility and autonomous system performance in any weather.
Incorporating new technologies into established development processes isn’t easy. This is why Siemens support customers such as Mercedes every step of the way. A dedicated engineer has been assigned to Daimler to facilitate the integration of Simcenter STAR CCM+ and train their staff to become expert simulation specialists.
One of the great benefits of the Simcenter portfolio is how it fosters closer collaboration between teams. It’s just as important to have close communication and cooperation between customers and Simcenter development engineers. This is why Simcenter Engineering Services are always on hand to offer assistance with any simulation tools – not only does it help customers to make best use of the products, but it also drives innovation at Siemens and influences the development path for future releases.