Editorial Type:
Article Category: Research Article
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Online Publication Date: 01 Sept 2008

Virtual Pattern Optimization Based on Performance Prediction Tools4

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Page Range: 192 – 210
DOI: 10.2346/1.2965831
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Abstract

Due to shorter development cycles and high cost pressure, the tread pattern development process is optimized by an analysis tool, which can predict the influence of the tread pattern on several tire properties. By using this tool conventional development cycles can be substituted by several virtual development cycles. The tool modules for the tire properties traction, handling, plysteer residual aligning torque (PRAT), groove wander, and noise are presented in this paper. The applicability of evolution strategy on tread pattern development is demonstrated, being another prerequisite for a future virtual pattern development process.

Keywords: tread pattern; performance prediction; traction; handling; PRAT; groove wander; noise; evolution strategy
Copyright: The Tire Society
FIG. 1.
FIG. 1.

Example of tire performance requirements for five tread pattern-related properties.

FIG. 2.
FIG. 2.

Tread pattern development process based on conventional and virtual development cycles.

FIG. 3.
FIG. 3.

Conversion of the tread pattern elements defined by vectors into a pixel-based image.

FIG. 4.
FIG. 4.

Definition of the Criff Index.

FIG. 5.
FIG. 5.

The impact of tire tread pattern structure on traction on various surfaces.

FIG. 6.
FIG. 6.

Qualitative description of the correlation between prediction and measurement of the braking/traction characteristics of tread patterns (data based upon approximately 30 tread patterns).

FIG. 7.
FIG. 7.

Specific longitudinal cx and lateral stiffness distributions cy of a winter tire tread pattern.

FIG. 8.
FIG. 8.

Mechanic relationship between tread pattern stiffness and cornering stiffness.

FIG. 9.
FIG. 9.

Correlation of the cornering stiffness between prediction and measurement.

FIG. 10.
FIG. 10.

Vehicle traveling straight ahead (lateral force Fy PRAT: plysteer residual aligning torque, PRCF: plysteer residual cornering force, aligning torque Mz slip angle α).

FIG. 11.
FIG. 11.

Distribution of shear stress τxy in the contact patch measured on a rolling smooth tire.

FIG. 12.
FIG. 12.

Local reaction force of individual tread blocks.

FIG. 13.
FIG. 13.

Correlation of predicted and measured PRAT values for tread pattern variations.

FIG. 14.
FIG. 14.

Interaction between tire and road surface.

FIG. 15.
FIG. 15.

Lateral force fluctuation F(y) of the road groove structure across a period (3∕4 in.=19 mm).

FIG. 16.
FIG. 16.

Correlation between subjective evaluation and simulated prediction of groove wander of tread patterns.

FIG. 17.
FIG. 17.

Display output of the noise module.

FIG. 18.
FIG. 18.

Correlation of differences between the predicted and measured noise levels in a coast by noise test in 37 pair comparisons of tread patterns.

FIG. 19.
FIG. 19.

Output example of a pattern generator setup for the pattern class “2 groove-directional.”

FIG. 20.
FIG. 20.

Basic sketch of evolution strategy applied to the development of tire tread patterns.

FIG. 21.
FIG. 21.

Pattern optimization for aquaplaning by evolution strategy; results compared to a serial pattern.

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