Macroscopical Modeling and Numerical Simulation for the Characterization of Crack and Durability Properties of Particle-Reinforced Elastomers

Numerical modeling of particle-reinforced or filled elastomers is a challenging task and includes the adequate representation of finite deformations, nonlinear elasticity, local damage as well as rate-dependent and rate-independent dissipative properties. On the structural scale, the permanent alteration of the material is visible as formation and propagation of discrete cracks, especially in the case of catastrophic crack growth and fatigue crack propagation. In this chapter, macromechanically formulated material models for finite viscoelasticity and endochronic elasto-plasticity of filled elastomers are presented in order to describe the material response of the undamaged continuum. On the FE-discretized structural scale, crack sensitivity of the material is assessed by the material force method. Material forces are used for the computational determination of fracture mechanical parameters of dissipative rubber material. Finally, arbitrary crack growth on the structural level is addressed by an adaptive implementation of cohesive elements. In a first application, crack propagation starting from an initial side notch in a tensile rubber specimen under mixed-mode loading is numerically predicted and compared to experimental observations. In a second example, averaged stress and energy based criteria are studied and compared with respect to their crack path predictability. In a third example, the durability of a tire design is numerically assessed by using the material force method