One step in the tire manufacturing process may be post cure inflation. In this step, the tire is cooled from cure temperature to below the glass transition temperature of the fabric cords while being held at a constant inflation pressure. Due to the thermal effects and creep of the component materials, the shape of the tire will be different after the post cure inflation than before. This change in tire shape from that in the mold drawings should be accounted for in performing finite element analyses to predict tire performance characteristics. This paper describes a modeling methodology that predicts the tire's shape change through the post cure inflation process using the finite element method. This is a complex process to represent analytically, with many different mechanisms contributing to the deformations of the tire. These include thermal expansion/shrinkage of the rubber and cords as they cool, creep of both the rubber and fabric cords, and change in material moduli. Since these mechanical effects are temperature dependent, the model uses results from the thermal history prediction model presented previously. The quality of the modeling process was assessed by comparing predicted to measured dimensions for several tire constructions and sizes. Selected results are presented to show the accuracy of the modeling procedure.

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