SAE J1988:2020 pdf free

SAE J1988:2020 pdf free.Residual Aligning Moment Test
LOADING AND POSITIONING SYSTEM一A fixture is provided to load and position the tire with respect to the surface of the simulated roadway at the Normal Force, Inclination Angle, and Slip Angle specified by the test engineer. It is important that angle positioning be consistent and free of bias. Results from machines which provide consistent data can be correlated. In a practical sense, it is not feasible to obtain the precise same data from two different test machines.
NOTE- Every test machine and all wheels DEFLECT by a small amount under load, therefore, the operating Inclination and Slip Angles existing during testing do not precisely equal the angles set by the load and positioning system. It is the responsibility of the test engineer to be aware of and account for system flexibility induced effects.
The loading mechanism shall have the ability to set the Normal Force on the tre to the commanded Normal Force with an accuracy equivalent to that specified for the Normal Force Load Cell throughout the range of the Normal Force Load Cell.
The goal of the positioning system is the ability to set the Inclination and Slip Angles to the commanded values with a target accuracy equivalent to the recommended accuracy specified for the Inclination and Slip Angle measurements in Table 2 over the range from ±1 degree.
MEASURING SYSTEM一The measuring system shall minimally measure the following variable according to the accuracies noted in Table 2. The ranges quoted for the measurement channels are minimum required ranges and are not to be taken as design limits for equipment. Further, the accuracies quoted are for single samples of a measurement channel and do not represent the ultimate accuracy of the results which are determined by the amount of sampling (averaging) chosen by the test engineer as a compromise of test time and precision. All reported data are to be matrix corrected for interactions.SAE J1988 pdf free download.