Cord Dynamic Properties for FEA Modal and Steady-State Dynamics of Tires

Tire cords are critical not only for the structural integrity of tires but also for influencing vehicle noise, vibration, and harshness (NVH) performance. However, their dynamic behavior is often oversimplified to elastic behavior in finite element analysis (FEA) simulations, and this oversimplification can lead to inaccurate modal vibrations predictions. This study shows how proper viscoelastic characterization of the storage and loss moduli of a polyester polyethylene terephthalate 1500/2 cord in terms of frequency and mean cord strain about which they are measured gives correct predictions of the steady-state vibration response of cord-rubber laminates. Dynamic properties of the polyester cord were used in FEA simulations of the polyester cord–rubber laminates in tension and dual cantilever beam bending vibration modes and compared with that obtained via experimental predictions. Storage and loss moduli of the rubber properties were also characterized in terms of frequency and mean strain and incorporated into the FEA simulation. Simulations using the viscoelastic cord properties were within 3 and 13% of experimental results in tension and combined tension and bending, respectively. By contrast, modeling the cord with only hyperelastic properties led to underpredictions of 100 and 34% with experimental results in tension and combined tension and bending, respectively. This finding underscores the importance of the proposed cord viscoelastic modeling for accurate NVH predictions.