Experiment And Finite Element Analysis Of Cord Pull Out Process

Cord-Rubber Composites is a kind of flexible composite materials, in which the cord is made of twisted-fiber bundles. Cord-rubber composite is wildely used in a wide variety of applications including Automobile tires, aircraft tires and buffer structures. In view of the nonlinear and large deformation properties of rubber and the twist structure of cord, the study of cord-rubber composites has high academic value and engineering significance.The first chapter gives a simple summary of the research status of cord-rubber composites and the extension-twist coupling characteristics of the cords. We also review the research status of the research methods of fiber pull-out test. We give a static analysis of cord in Chapter two. We propose the extension- twist coupling factor of the cord . Cord is equivalent to a anisotropic material, the stress- strain relationship is determined based on the Strain energy conservation law. The geometrical parameters of the cord involved in this paper, such as the cord twist, sectional area, were studied in the third chapter.We also carried out the cord H-pull test at room temperature in Chapter three in order to obtain rubber composite interface strength parameters, The reason of different morphology of the pulled out cord is discussed. We get the load-displacement curve in the process of cord pull-out. Cord-rubber composite has complex failure interface modes, because of the large deformation of the rubber and the geometric characteristics of cord.The process of interfacial debonding and frictional sliding in cord H-pull test is simulated using finite element method in Chapter four. To improve the convergence of of the nonlinear large deformation analysis, we use different model when analysis the process of interfacial debongding and interfacial frictional sliding. The numerical scheme is then further applied in a parametric study of the effects of the friction coefficient and the process-induced residual stresses on the cord-rubber interface failure process. The results showed that: (1) the critical interface fracture energy has a greater effect on the cord pull out process. (2) cohesion sliding resistance has a greater effect than friction coefficient on the process of frictional sliding. (3) the effect that residual strain on the maximum load of process of frictional sliding is not obvious.