Study of Fracture Behavior of Cord-Rubber Composites for Lab Prediction of Structural Durability of Aircraft Tires

An aircraft tire durability study is underway to investigate the deformation and fracture behavior of cord-rubber composites. This study will identify the important parameters responsible for the structural failure of aircraft tires by the use of analytical and laboratory prediction methods. These methods will also identify the interaction between material property degradation and damage accumulation in cord-rubber composites. Preliminary results using coupon specimens of tire carcass have revealed that prolonged static and cyclic loading sequences produce extensive interply shear deformation at the free edges resulting in cord-matrix debonding followed by delamination type failure. These loading sequences represent the circumferential tension in the footprint region of aircraft tires. It was also determined experimentally that a fatigue endurance limit can be established for cord-rubber composites. Analytical methods using finite element models of coupon specimens have demonstrated reasonable accuracy in predicting load-displacement response and interply shear strain variations. Future plans will include the correlation between the fatigue resistance data of composite specimens and dynamometer test results of actual tires.