PSI - Issue 75

Said Allouch et al. / Procedia Structural Integrity 75 (2025) 299–310 S. Allouch/ Structural Integrity Procedia (2025)

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new load program. This ensures that the load spectrum accurately reflects the operational conditions, safeguarding the reliability of structural assessments. 4.2. Vehicle type Different vehicle types experience varying load conditions due to differences in mass, suspension setup, and intended usage. Passenger cars, SUVs, sports cars, and super sports cars each impose unique stress profiles on the wheels, necessitating tailored load profiles for each category. Load programs are only valid for the same vehicle type, as each type generates distinct loading conditions. Any change in vehicle type leads to different load characteristics, requiring the development of new load files to accurately capture these conditions. Without adapting the load file accordingly, the load file would fail to reflect the actual stresses experienced by the wheels, potentially compromising structural integrity and durability assessments. 4.3. Usage of Vehicle The operational profile of the vehicle, whether it is used for urban commuting, highway driving, off-road exploration, or track racing, affects the loading conditions. Frequent cornering, braking, acceleration, and surface transitions contribute to dynamic forces that shape the design spectrum. If special usage can be expected, such as off-road driving or track racing, an adjusted load file is required to accurately capture the unique stresses imposed on the wheels. This ensures the design spectrum reflects the actual operating conditions and maintains the reliability of structural assessments. 4.4. Test Machine BiAx testing machines typically have two primary configurations: inner drum and outer drum machines. In inner drum machines, the load is applied against a rotating inner drum including side rings which directly contact the tire. Outer drum machines apply load against a rotating outer drum without side rings, providing a different type of stress distribution compared to inner drum machines due to different curvatures. The distinction between these two configurations is significant, as the load application mechanisms differ, leading to different strain distributions and stress patterns on the wheels. According to SAE (International, 2021), three different types of inner drum machines are defined: Type A, Type B, and Type C, which differ in mechanisms. The outer drum machines have similar control concepts built by different manufacturers. All these machine types are illustrated in Fig. 4.

Fig. 4. BiAx/ZWARP machines.