Tire performance prediction method and method of designing tire

A tire performance prediction method of predicting performance of a tire on a snowy road surface based on a physical quantity generated in at least any one of a tire model and a snow model, by using the tire model having a tread pattern deformable by at least one of ground contact and rolling and a snow model representing the snowy road surface to be in contact with the tire model, wherein

• the snow model is modeled as an elasto-plastic body or a plastic model,
• the snow model represents non-linearity of a volume compaction property of snow by a relation between a density of the snow or a volume strain of the snow and a pressure on the snow,
• the snow model represents a shear property of the snow by a relation between a yield stress of the snow and the pressure on the snow, and
• in the snowy-road-surface model represented by the snow model, the non-linearity of the volume compaction property of the snow is expressed as a piecewise-linear continuous function which is based on the relation between the density of the snow or the volume strain of the snow and the pressure on the snow, wherein
• the piecewise-linear continuous function is sectioned in a unit of 0.1 MPa or smaller in a section where a stress of 0.5 MPa or smaller is applied to snow, and the piecewise-linear continuous function is sectioned in a unit of 0.3 MPa or smaller in a section where a stress if larger than 0.5 MPa is applied to snow.