Fraunhofer Institute for Industrial Mathematics ITWM, Kaiserslautern

 

Director: Prof. Dr. Dieter Prätzel-Wolters

Contact: Dr. Michael Burger

 

© Fraunhofer ITWM

The department »Mathematical Methods in Dynamics and Durability« at the Fraunhofer Institute for Industrial Mathematics ITWM is concerned with modeling and simulation of usage variability, dynamic loading and energy efficiency of vehicles and machines.

We are developing statistical methods for durability, reliability and energy efficiency. Our software development projects »Virtual Measurement Campaign (VMC)«, »Usage Simulation (U·Sim)« and »Statistics for Fatigue Testing and Reliability (Jurojin)« combine statistical and simulation methods with geo-referenced data in a unique novel way.

Our products support the entire process from the description and modeling of the usage variability, which arises due to the combination of different mission profiles or driver behaviour and the varying environmental conditions in different regions of the world, the derivation of reference loads and consumption related quantities to the design of rig tests or reference routes. The underlying methodological approach is mainly motivated by the desire to understand usage variability and the resulting scatter in loads or fuel consumption and to provide methods for making use of that information within vehicle development. Because of the rapidly growing availability of potentially relevant data such as traffic density and because of upcoming new requirements with respect to specific applications, we are continuously developing and extending the database as well as the collection of methods.

»VMC Simulation« is an important part within these activities: VMC Simulation provides the possibility to simulate vehicle loads and performance based on suitable vehicle and driver models embedded in an environmental model, which obtains its key information from the VMC geo-referenced database. The utilized models feature longitudinal, lateral and vertical dynamics. They can be used to predict vehicle loads for different vehicle and driver types, on different routes in the world and, thus, reveal a deeper insight in the effects of locally different conditions. When addressing vertical dynamics the stimulation road roughness and travelling on the road with a specific speed profile are essential. The software provides methods to compute road roughness indices (e.g. the international roughness index (IRI)) from measured road profiles as well as methods to compare different indicators. VMC Simulation also allows to generate road profiles based on a given set of indicators (using stochastic processes) Moreover, if information about the vehicle suspension is available (sprung/unsprung masses, stiffnesses and damping characteristics), VMC Simulation is able to estimate vertical forces and damage indicators. We also offer methods to back-calculate road profiles from measured vehicle quantities (such as accelerations and spring displacements) on request.

Use Cases

  • Drivetrain development:
    • Calculation of vehicle and drivetrain loads on routes in different regions of the world.
    • Prediction of customer-specific usage profiles in terms of drivetrain characteristics (e.g. engine speed and gear collectives).
    • Fast derivation of reference routes for analyzing real driving emissions (RDE) and developing advanced driver assistance systems (ADAS).
  • Fuel Consumption and efficiency: Estimation of fuel consumption, prediction of potential savings and assessment of constructive modifications.
  • Durability: Estimation of longitudinal, lateral and vertical loads for the development of chassis, suspension and other components.