VIBRATION TRANSMISSION OF PNEUMATIC TIRES (FINITE-ELEMENT)
Abstract
Natural frequencies and mode shapes of a tire with fixed- and movable-wheel are obtained using a 12-d.o.f., geometrically nonlinear, doubly curved, laminate composite, thin shell finite element of revolution. Software is developed for 3-D display of the tire mode shapes. This allows an interpretation and classification of mode shapes beyond those that have been presented in the literature. Theoretical results are compared with experimental ones and good agreement is shown. By comparing the results of the movable-wheel tire with those of the fixed-wheel tire, it is found that only the radial modes of n = 1 are affected by the wheel's freedom to move. To evaluate the finite element modeling, an analytical ring-spring model is investigated. The tire is modeled as a circular ring supported by distributed spring while the wheel is modeled as a rigid mass to which the distributed spring is attached. It is found that the two models, one complex and one simple, agree and complement each other. A method for calculating the steady state displacement response and force transmission is developed for the wheel axle of a tire-suspension system undergoing a steady state excitation at the ground contact. The method requires that the frequency response functions (or receptances) of both tire-wheel and suspension units be available. The receptances to the tire-wheel unit are obtained using the modal expansion method while the suspension receptance is obtained through other means. This method allows freedom in designing a vehicle and its tires independently while meeting performance requirements. Examples of some applications of the method developed are presented. It is found that the radial modes of n = 1 are the primary contributors to the vibration transmission of tire through wheel axle. Damping in the sidewall region is found to be effective in reducing the vibration transmission. It is also found that the wheel axle displacement and force are less sensitive to the footprint pressure distribution in rolling than in cross sectional direction.
Degree
Ph.D.
Subject Area
Mechanical engineering
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