Parallel-kinematic LBF® road-street simulator reproduces load standards realistically and shortens test time

The newly developed test rig concept realistically reproduces the wheel loads in all degrees of freedom of the vehicle and allows a comprehensive reduction of the test time – compared to real tests on test tracks. In addition the updated simulation software LBF®.DAP, which allows a decrease down to one third of the original test time of complex trials, while retaining the characteristic load profiles.

For engineers in R&D, experimental and virtual test technologies for the design and manufacturing of new vehicles and components are standard tools to improve safety, quality, durability and environmental friendliness of automobiles in a sustainable manner. Therefore, the goal is a sound balance of low weight, reliability and an optimum of cost and resources as well as a reduction of test time to speed up development processes.

“The concept of a fully kinematic wheel test facility represents an entirely new generation of wheel test rig, which follows the tradition of patented ZWARP test, and allows at the same time an improved quality of the laboratory simulation of wheels and hubs for cars.” says Rüdiger Heim, head of the competence center Wheel / Hub / Axle at Fraunhofer LBF. The specific characteristics of the wheel-road simulator lie in the field of parallel kinematics, a novel application for wheel test rigs, as well as an internal drum connected directly to the electric motor by a flange. The hexapod platform for the attachment of the wheel and hub allows controlled translational and rotational movement of the wheel in all relevant degrees of freedom and offers an unprecedented flexibility in the use of standardized load programs – such as those offered by Fraunhofer LBF, the work group wheel (Arbeitskreis Räder – AKR) and SAE International.

Furthermore, researchers from the Fraunhofer Institute for Structural Durability and System Reliability LBF show enhanced developments of standard test technologies as well as customized testing methods for:

– the characterization and testing of elastomer components,
– load-stress measurements and analysis during operation,
– testing of trailer coupling systems.
The new testing technologies offer a more realistic and more efficient testing of standard components as well as procedures and methods especially developed and adapted for new materials and components . Virtual simulation plays a decisive role in the reduction of development time and production costs as well as in the improvement of the product life cycle, the utility value, the weight optimization and increase of operational safety. Oliver Ehl, managing director of S & S GmbH, a spin-off company of the Fraunhofer LBF, which creates individual software solutions for the structural and system analysis, developed a computerized method in order to capture the multiple, complex effects and interactions of the parameters which determine the life cycle of wheels (loads, tires, geometry and material).

“Embedded in our software LBF®.WheelStrength, the structural durability assessment of the wheel can be carried out as early on as the predevelopment stage. At the same time the virtual model allows the optimization of the design before even producing the first prototype. This shortens development time and shows specifically where improvements can be made,” says Ehl.

Fraunhofer researchers will be informing about further areas of application of new testing technologies in the automotive industry in short lectures in hall 1, booth 1956. The main exhibit is a racing car, on loan from the racing team of the Technical University of Darmstadt, which illustrates the experimental and virtual testing in the automotive industry.