Measurement of the Tire Dynamic Transfer Stiffness at Operational Excitation Levels

The tire dynamic transfer stiffness describes how a displacement enforced at the tire contact patch results in a force at the spindle-wheel interface. The dynamic transfer stiffness is expressed as a function of frequency and provides insight in the generation of vehicle interior structure-borne tire/road noise. The road surface texture excites the tire at the contact patch, resulting in structural waves travelling around the circumference of the tire. The tire sidewalls transfer these vibrations to the rim. The vibrational energy is then transmitted through the spindle-wheel interface toward the suspension and vehicle body. The resulting body panel and window vibrations cause noise radiation in the passenger compartment. It is known that the tire dynamic properties are dependent on the vibration amplitude. Therefore, the excitation levels during tire dynamic characterization tests should be similar as the excitation levels during operation of the tire. This is not possible with the classic excitation devices such as hammer and electrodynamic shakers. This paper presents an experimental method to obtain the dynamic transfer stiffness of a non-rolling tire which is excited at operational excitation levels. Therefore, a high-frequency 6-DOF hydraulic shaker table (CUBE) is used to excite the tire. The shaker table provides the static preload and excites the tire at the contact patch in the frequency range 20-235 Hz. The force at the fixed spindle is measured by a piezo-electric dynamometer.status: publishe