| Rubber-metal bonded components are widely used in the engineering forapplications such as suspension and mounting systems. Mechanical properties of rubberin terms of both material and geometric nonlinear behavior also make it difficult to getsimple and rigorous solutions to product design problems. The rapid development of thenumerical simulation technology and finite element analysis programs handlinghyperelastic material have provided a powerful means to further the study,understanding, and optimization of rubber in engineering applications.This paper, based on a three-dimensional finite-strain formulation, presents apseudo-elastic model of the Mullins effect in rubber components. Mullins effectformulation results and FEA results of simple tensile rubber samples are in consistentwith Mullins&Tobin’s simple tension experimental data. On this condition, the Mullinseffect parameters for two different rubber constitutive models of rubber components aregiven.In consideration of fracture mechanics problem on rubber sheet with oblique edgecrack, nonlinear finite element method is employed to predict possible extendedorientation of crack. This method can also be used to calculate the J intergral around thecrack tip angle for different rubber constitutive models with an initial crack which hasdifferent inclination and depth. The results of maximum J intergral direction around thecrack tip illustrate the possible direction of crack growth initiation.By calculation, it’sfound that the direction of the crack extension is influenced by the initial crackinclination and depth but has nothing to do with the rubber material constitutive. It isalso shown that the crack extension orientation isn’t along with the initial orientation ofcrack but with a certain angle, and the angle is gradually decreasing with the initial angleof oblique crack increasing. The finite element model with initial interface crack inrubber bimaterial and rubber-steel bimaterial is founded, and the plain stress nonlinearfinite element approach is employed to analyze the direction of crack extension. TheJ-intergral around the interface crack tip for different material constants and crack depthis calculated, and the J-intergral as a function of the stretch ratio and initial crack depth is evaluated. For small crack, the crack grows towards the softer rubber material. Whilefor large crack, the crack extends along interface. Cohesive zone models are used tosimulate rubber-steel biomaterial interface, and cohesive elements are used to simulatethe interface damage and crack growth at rubber-steel bimaterial interface.The failure mechanism of rubber-steel bimaterial and the crack growth mechanismof rubber sheet crack and interface crack are studied. The research results are applied tothe rubber-steel sphere bush and the shear pattern of rubber vibration absorber. Thefailure mechanism of the interface crack between steel and rubber is also studied.Nonlinear finite element method was used to simulate numerically a model ofrubber-steel sphere bush with a central penny-shaped crack, circumferential edge crackand elliptical surface crack in bonded interface and the middle rubber layer. The methodwas also used to simulate numerically a model of shear pattern of rubber vibrationabsorber with corner crack and edge crack. The relation curves between tearing energyand crack length has been given, and compared the results on two kinds of materialmodels. At last, the empirical formulas of tearing energy calculation of rubber vibrationabsorber have been gained by multiple non-linear data regression. It provides atheoretical basis in the actual product design of rubber-steel component. |
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