2019 / Integrated mobility technologies

Use of virtual technology protection

    We all know the picture: A vehicle prototype equipped with countless sensors collides full frontal with a wall. The crumple zone earns its name and the dummies make friends with the air bag.

    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.

    A promising way to drastically reduce these costs is virtual technology protection: Engineers like Nijaz Dizdarevic simulate the entire process on a computer. These digitalisation measures not only drastically reduce costs but also greatly accelerate the development process.

    The variety of virtual crash tests

    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.

    A question about produceability

    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:

    We are in a kitchen - and we try to mix the ingredients correctly so that we get the anticipated result

    Nijaz Dizdarevic

    Despite only Alexander and Nijaz knowing the ingredients list and recipe, this does not necessarily mean that the kitchen will also look, in the end, like the pictures in a cookbook. If something does not work as expected with cakes and pastries, simply coat small problem areas with chocolate icing. No one tolerates these inaccuracies in automotive development: ‘Our aim is to identify and eliminate all possible problem areas in a purely virtual manner’, Nijaz summarises, ‘and this includes each step from production to functional design.’ Therefore, PSW creates the whole process chain virtually, and with this hopefully lays the foundation stone for completely prototype free development in the near future.

    Die virtuelle Technologieabsicherung senkt nicht nur die Kosten drastisch, sondern beschleunigt auch den Entwicklungsprozess enorm.

    Achieve more together

    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.

    Virtual development, simulation

    We are advancing the progress of prototype-free development through the use of Multi Domain Simulations (CAX) and the expansion of our virtual reality expertise.

    Quantum leap through a quantum computer?

    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.

    If we were to simulate the flight physics of a commercial aircraft, it would not matter if coffee was served or not

    Alexander Kindsvater

    The assessment from the level of detail and precision of results requires intuition, but perhaps not for much longer: For instance, quantum computers could increase the simulation precision to a wholly new level in the near future. Of course it doesn’t matter how true to detail the calculations are. There is always room for improvements. In the validation phase Alexander and Nijaz compare their simulated results with those legally required prototype tests, to identify each slight deviation: “These findings are the basis for us to continually improve our models, simulations and methods.”

    Cheaper, faster, simpler

    Whether Alexander’s and Nijaz’s department only develops individual components or a whole vehicle, as in the case of the Audi A5 Sportback, the advantages for their customers are clearly to hand: The simulations save them time and money. In addition, virtual technology protection reduces the complexity: Simple changes to the simulation parameters align tests to regional regulations of international target markets without any problems. An expense disproportionate to real prototypes. With an experienced team like PSW, automotive manufacturers acquire invaluable expertise in-house, so that they make some great steps forward on the way to complete prototype free development. Ideally only the load cases prescribed by law still remain after the work of Nijaz and Alexander, which must finally be tested using real vehicles. Normally, these only confirm what the PSW simulation experts already confirmed virtually.

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