PSI - Issue 75

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

308 10

stress distribution and deformation. They are commonly used in heavy-load applications and scenarios requiring increased durability and impact resistance.

Fig. 9. Wheel design: (a) disc wheel; (b) spoke wheel.

While disc wheels feature a continuous, solid structure connecting the hub to the rim, spoke wheels consist of individual spokes that connect the hub to the rim, creating an open structure. This design typically reduces the overall weight of the wheel and improves heat dissipation but results in a more complex load path. The forces applied to the rim are transmitted through the individual spokes, leading to localized stress concentrations and greater flexibility. As a result, spoke wheels can exhibit higher internal stresses under load and are more sensitive to dynamic forces. Importantly, 'spoke wheel' in this context does not refer to wheels with pre-tensioned wire spokes, as commonly seen in Oldtimers, bicycles, or motorcycles. The structural differences between the two designs mean that they respond differently to the same load conditions, which has a direct impact on damage assessment and load program validity. 5.3.1. Details of the investigation The study setup followed the same procedure outlined in the tire ratio (4.7.1), with the slight parameters change shown in Table 2.

Table 2. Details of the used measurement wheel.

Vehicle type

Wheel size

Tire

Wheel load [kg]

Tire pressure (flat track | ZWARP) [bar]

Torque [Nm]

Passenger car

8.5x19

245/45R20

740

3 | 4

140

5.3.2. Results and Analysis

Initially, peak loads were applied to derive RFS values using the LBF design spectrum for both disc and spoke wheel designs on the flat track roll rig. A load file was then created specifically for the disc wheel, and RFS values were measured using the BiAx machine, Fig. 10. Table 3 and Table 4 summarize the results concerning the deviations of the load file to the design spectrum. Comparing the RFS values obtained from the LBF design spectrum and the BiAx machine revealed deviations within ±5%, confirming the load file's validity for the disc wheel. To assess its applicability to the spoke wheel, the same load file was tested under identical conditions. However, several strain gauges registered deviations exceeding ±5%, indicating notable discrepancies in the damage assessment. This result implies that using the disc wheel’s load file for the spoke wheel would underestimate the loads, making the load file unsuitable for the spoke design.