Wheels are safety-critical components of any vehicle and are exposed to severe loads over their lifetime. Their reliability can only be safeguarded by performing tests under laboratory conditions which resemble actual loading conditions as closely as possible. Based on an idea from the Fraunhofer Institute for Structural Durability and System Reliability LBF, the Biaxial Wheel Test Facility has been completing validations since the early 1980´s. This test procedure became a standard at most European wheel producers and was also introduced as SAE wheel standard J 2562, in 2003. Standardized load profiles like Euro-Cycle or AK-Cycle had been developed which could reduce the test time to a minimum by transforming damage content of the original design spectra of 300,000 km to an accelerated one of only 10,000 km. Today, an additional method for the generation of a load profile is available. By using the “Hayes Lemmerz” method the ZWARP’s control parameter could be determined directly from the wheel forces without the need for the long detour of a strain gauge measurement.
The Challenge
Wheels are critical safety-relevant components of the vehicle which are exposed to severe loads over the lifetime. Their reliability can only be safeguarded by performing tests under laboratory conditions which resemble actual loading conditions as closely as possible.
Our Solution
The Biaxial Wheel Test (ZWARP) developed by Instron includes an additional hydraulic actuator which allows a controlled and highly accurate adjustment of the angle of attack to produce high lateral forces. It is also distinguished by its compact design, high robustness, and extremely high reproduction quality.
By using this so-called “Hayes Lemmerz” method, the ZWARP’s control parameter could be determined directly from the wheel forces without the need for the long detour of strain gauge measurement.