Belt Test for the Evaluation of the Fretting Fatigue and Adhesion Behavior of Steel Cord in Rubber

An endless belt test to investigate the fretting fatigue and dynamic adhesion behavior of steel cord has been developed in the laboratory. The specimen consists of an endless belt with steel cord reinforcement in the circumferential direction. The choice of the testing conditions (stress levels) has been made so as to simulate as well as possible the maximum stresses produced in a running truck tire carcass.

The percentages of loss in cord breaking load have been measured after twenty million cycles, which equals a mileage of 72 000 km for a 11.00 R 20 tire of 16 ply rating (PR). Those percentages of loss have been measured on separate wires taken from three cords.

Further, the adhesion level before and after fatigue can be measured in a cord peel test, which consists of peeling three belt cords, each cord separated by another cord.