Experimental Evaluation of Tyre Vertical Dynamic Stiffness and Damping for Ride Model Applications Using Flat Trac

The damping and vertical dynamic stiffness of a tyre are critical to ride comfort and overall dynamics, particularly for low-frequency excitations in urban and highway driving. Accurate ride models depend on precise tyre parameterization, as tyres are the primary interface between the vehicle and the road, absorbing surface irregularities before the suspension engages. This study investigates an experimental methodology characterizing the vertical dynamic behaviour of pneumatic tyres using a Flat Trac test machine. Contrary to the conventional approaches that depend on intricate shaker rigs or frequency dependence function models, the proposed technique uses a realistic force displacement loop-based technology which is appropriate for ride model applications. Dynamic stiffness is calculated as the peak force divided by peak displacement during vertical sinusoidal excitation. Damping is derived from hysteresis energy loss per cycle. The tests were conducted under various conditions by varying vertical loads, inflation pressures, excitation frequencies, and deflection amplitudes (4–8 mm). The generated stiffness and damping curves from the test results could be directly applied in quarter-car models and could potentially be extended to the full-vehicle ride simulations for ride characteristics assessment studies. Research indicates that the dynamic stiffness of a non-rolling tyre is consistently higher than that of a rolling tyre. Under rolling conditions, dynamic stiffness increases with test speed due to excitation frequency effects. Additionally, vertical dynamic stiffness correlates positively with inflation pressure; increasing it from 216 to 264 kPa (±10% of rated pressure) yields a 12–14% rise in stiffness for both rolling and non-rolling condition. The proposed framework facilitates the integration of realistic tyre vertical dynamics into vehicle ride models while maintaining minimal complexity, thereby improving simulation fidelity and supporting better design and evaluation of ride quality in early-stage vehicle development.