Affiliations: Departamento de Mecânica Computacional,
Universidade Estadual de Campinas, Rua Mendeleiev, s/n, Cidade
Universitária "Zeferino Vaz", 13.083-970, Campinas, SP, Brazil
Abstract: Large Finite Element (FE) models of tires are currently used to
predict low frequency behavior and to obtain dynamic model coefficients used in
multi-body models for riding and comfort. However, to predict higher frequency
behavior, which may explain irregular wear, critical rotating speeds and noise
radiation, FE models are not practical. Detailed FE models are not adequate for
optimization and uncertainty predictions either, as in such applications the
dynamic solution must be computed a number of times. Therefore, there is a need
for simpler models that can capture the physics of the tire and be used to
compute the dynamic response with a low computational cost. In this paper, the
spectral (or continuous) element approach is used to derive such a model. A
circular beam spectral element that takes into account the string effect is
derived, and a method to simulate the response to a rotating force is
implemented in the frequency domain. The behavior of a circular ring under
different internal pressures is investigated using modal and
frequency/wavenumber representations. Experimental results obtained with a real
untreaded truck tire are presented and qualitatively compared with the simple
model predictions with good agreement. No attempt is made to obtain equivalent
parameters for the simple model from the real tire results. On the other hand,
the simple model fails to represent the correct variation of the quotient of
the natural frequency by the number of circumferential wavelengths with the
mode count. Nevertheless, some important features of the real tire dynamic
behavior, such as the generation of standing waves and part of the
frequency/wavenumber behavior, can be investigated using the proposed
simplified model.
