Paper Number 5.4
Modeling Material Storage Modulus
for Tire Natural Frequency Prediction
Robert Wheeler
Ron Kennedy
Hankook Tire
Akron Technical
Center
3535 Forest Lake Drive
Uniontown, Ohio 44685-8105
Email:
wheeler@hankook-atc.com
This research deals with the material storage
modulus aspects of tire natural frequency predictions in the low to mid
frequency range (0 to ~200 Hz) using finite element analysis (FEA). Obtaining accurate predictions is important for
ride, handling, durability, and NVH
design. FEA models are often used either
directly or indirectly to generate associated specialized models for
simulations of events within each of the aforementioned areas of performance. Known nonlinearities of the storage modulus
associated with strain state make it difficult to obtain accurate
representations of the tire stiffness for both steady state loading and natural
frequency predictions. The proposed
method introduces separate linear elastic representations of the storage
modulus in implicit solutions to account for these nonlinearities. The method is shown to be sufficient for
accurate prediction of natural frequencies for static and steady state rolling
loading events. It provides the benefit
of reduced testing associated with material characterization and reduced
simulation times making it a valuable design tool. Material characterization tests are performed
at appropriate strain states for non-rolling, steady state rolling, vibratory,
and combined rolling and vibratory conditions (bi-modal). The predicted natural frequencies are
validated with measurements using modal tests.
Non-rolling tire modal tests are performed using SAE
J2710 recommended procedure in which the tire is attached to a fixed spindle.
Rolling tire modal tests are performed using a pseudo free-spindle boundary
condition.