Use of virtual technology protection

The event is played in super slow motion. As spectators we can only guess the speed of the car. A regular person only sees a spectacular crash, but to the automotive engineer the test is a massive source of valuable data: How do the individual components behave? What forces act on what component connections? Do the transformations reach a critical level?

No matter where in the world: Nowadays no vehicle is allowed on the road without these tests. And that’s how it should be since this primarily concerns the safety of the passengers. Of course the more informative it is for designers, developers and passenger safety experts to crash cars in a controlled setting, the more expensive the measures are for the automobile manufacturer. Each crash costs millions.

Nijaz is responsible for the virtual technology protection of the entire chassis design at PSW. What does ‘virtual technology protection’ exactly mean? Does Nijaz spend the whole day in front of a computer screen and drive 3D models of vehicles against polygon walls? Like a computer game? Not really.
Instead, Nijaz tests each conceivable load case for each individual chassis component virtually. Load cases are all possible scenarios which could affect the vehicle chassis during everyday road traffic in any way. Therefore, it in no way only concerns extreme cases like a frontal impact. A load case can also be quite simple: ‘Close door’. Even intentionally simple hand grips can measurably affect the chassis seal or even the door. In the next load case Nijaz ensures that the car headlights don’t shake, when the car quickly drives over cobblestones. And so on.

On the one hand the virtual protection computes the vehicle protection and on the other hand the producibility. At the same time the way in which virtually developed components can later be produced as planned must be determined. This is the specialist area of Alexander Kindsvater, who encountered Nijaz’s team at the start of the year as an expert for production and thermal distortion simulations. During the manufacture of vehicle components, parts are often formed and connected with pressure, heat or chemical processes. Of course, this has an effect on the material and how it later behaves in a load case. Above all, in the case of paintwork in the KTL immersion bath (‘cathodic dip coating’), the suitabilityof newly developed chassis parts to real circumstances must be put to the test. But that’s not all: If a component always changes in the planning, Alexander tests it again to see whether there are consequences for the active material or systems used. He describes his task at PSW as follows:

Close collaboration is the key to the holistic approach of PSW: While Alexander is preoccupied from day to day with the question of how to best produce a newly designed component, Nijaz continues to evaluate the functionality of the planned components. Both the production and functional design branches complement each other perfectly, whereby numerous interfaces yield other PSW departments: For instance a car body must also comply with aerodynamic factors (more about this in the article on page 30) and design likewise plays a decisive role.

Since complete vehicle models are also always needed for virtual crash simulations, the responsible colleagues are also regularly in the same boat for attachment parts and vehicle safety. The common denominator for all tasks: The smallest changes, for instance to the functional design or production parameters, always affect the whole. Therefore, Nijaz and Alexander always consider all components individually and together in component groups, as well as in the context of the entire vehicle body. It is only logical and consistent for them to carefully secure small details virtually. With real hardware this would take a lot longer, but with a computer simulation this is a matter of hours to days.

Vehicle simulations that include everything from the raw material to the material bonding and finish up to the individual production steps are a relatively new approach. PSW is performing real pioneering work here. Alexander and Nijaz are so painstaking that the limitations of the current computer generation are a bottleneck for them. This is logical since the more detailed the work, the more complex the physical calculations. Two days computing time are easily needed to simulate a frontal impact with a fully developed virtual prototype in the high performance cluster of Audi AG. Therefore, the abstraction helps the specialists in many of their tasks: Instead of the parameters of each individual screw being true to detail, some components are only given essential basic characteristics. Alexander has a convincing comparison for this.